# MEASURED EMISSIONS DATA FOR USE IN EVALUATING THE ULTRA-WIDEBAND (UWB) EMISSIONS LIMITS IN THE FREQUENCY BANDS USED BY THE GLOBAL POSITIONING SYSTEM (GPS)

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# Project TRB 02-02

# Report

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# October 22, 2002

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# Technical Research Branch

# Laboratory Division

# Office of Engineering and Technology

# Federal Communications Commission

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# Prepared by

# Steven K. Jones 

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# TABLE OF CONTENTS

**EXECUTIVE SUMMARY i**

**SECTION ONE -- INTRODUCTION 1**

**BACKGROUND 1**

**OBJECTIVE 3**

**APPROACH 3**

**SECTION TWO -- DESCRIPTION AND USE OF**

> **THE FREQUENCY BANDS EXAMINED 5**

##  GPS APPLICATIONS 5

**GPS L1 FREQUENCY BAND 5**

**GPS L2 FREQUENCY BAND 6**

**GPS L5 FREQUENCY BAND 7**

**ARNS FREQUENCY BAND 7**

**SECTION THREE -- DERIVATION OF THE**

**UWB EMISSION LIMIT 8**

**SECTION FOUR -- MEASUREMENT SYSTEM**

**AND PROCEDURES 11**

**MEASUREMENT SYSTEM DESCRIPTION 11**

**MEASUREMENT SYSTEM CALIBRATION 12 OVERALL MEASUREMENT SYSTEM GAIN 14**

**MEASUREMENT PROCEDURES 14**

**SECTION FIVE -- MEASURED DATA 15**

**AMBIENT EMISSIONS MEASUREMENTS 15**

**Ambient Emissions Measurement Locations 16**

**Ambient Emissions Measurement Data 17**

**RADIATED EMISSIONS MEASUREMENTS 19**

**Consumer Device Sample Set 20**

**Consumer Device Radiated Measurement Data 20**

**SECTION SIX -- RESULTS 22**

**AMBIENT EMISSIONS MEASUREMENTS 22**

**RADIATED EMISSIONS MEASUREMENTS 22**

**SECTION SEVEN -- OBSERVATIONS AND CONCLUSIONS 30**

**OBSERVATIONS 30**

**Ambient Emissions Measurements - Outdoor Sites 30**

**Ambient Emissions Measurements - Indoor Sites 30**

**Radiated Emissions Measurements 31**

**CONCLUSIONS 32**

**APPENDIX A -- MEASUREMENT SYSTEM**

> **CALIBRATION DATA A-1**

**APPENDIX B -- MEASUREMENT PROCEDURES B-1**

######## APPENDIX C -- DATA FROM AMBIENT MEASUREMENTS - 

######## OUTDOOR SITES C-1

######## APPENDIX D -- DATA FROM AMBIENT MEASUREMENTS - 

######### INDOOR SITES D-1

######## APPENDIX E -- DATA FROM RADIATED EMISSIONS

> **MEASUREMENTS E-1**

# MEASURED EMISSIONS DATA FOR USE IN EVALUATING THE ULTRA-WIDEBAND (UWB) EMISSIONS LIMITS IN THE FREQUENCY BANDS USED BY THE GLOBAL POSITIONING SYSTEM (GPS)

**EXECUTIVE SUMMARY**

On February 14, 2002, the Federal Communications Commission (FCC)
adopted the First Report and Order (R&O) authorizing the limited use of
Ultra-Wideband (UWB) devices on an unlicensed basis under Part 15 of the
FCC rules. UWB devices operate by employing very narrow or
short-duration pulses that result in an extremely wideband frequency
spectra. UWB technology holds great promise for a vast array of new
applications with the potential for providing significant benefits to
public safety operations, as well as business and consumer applications.

The UWB R&O establishes average limits for UWB emissions in the form of
application-based emission masks. In the 960-1610 MHz frequency range,
the emissions limits defined by these masks are predicated on the
protection of current and future Global Positioning System (GPS)
operations. Many of the parties providing public comments within the UWB
proceeding have expressed concerns over the aggregation of conservative
assumptions used in the derivation of these emissions limits.

The Commission recognizes the growing importance of GPS in everyday life
and is committed to ensuring that the GPS signals are not degraded or
interrupted as a result of radio frequency interference. However, the
Commission is also committed to fostering the development and
implementation of promising new radio communications technology. As
such, the Commission must carefully balance the need to protect critical
services like GPS from interference without placing unnecessary burdens
on developing technologies such as UWB.

The following statement was included in the text of the R&O: "It is our
belief that the standards contained in this Order are extremely
conservative. These standards may change in the future as we continue to
collect data regarding UWB operations." This measurement effort
represents a first step in collecting data to assist in an assessment of
these standards in accordance with the Commission's commitment to
re-examine the UWB rules within six to twelve months of the initial
release of the R&O. Since very few UWB devices had actually reached the
marketplace at the time this effort was initiated, it was decided that
this first step assessment would focus on an evaluation of some of the
assumptions that were integral to the derivation of the emission limits
for UWB devices. In particular, this effort concentrates on an
examination of pre-existing emissions and associated amplitude (power
density) levels present in those frequency bands that were identified as
requiring extreme protection from UWB operations.

A measurement approach was developed to determine the existing level of
ambient RF activity within these specific frequency bands. A set of
locations was identified from which to perform the measurement of
existing ambient RF activity based on the likelihood of UWB-to-GPS
interactions. These locations are separated into two distinct
categories, outdoor locations and indoor locations. Seven outdoor sites
were identified for performing these measurements, including airports,
seaports, train yards, and industrial sites. These sites were selected
primarily because GPS has been cited as a key navigational component for
use in aviation, maritime, rail, and automotive transportation systems.

Eight measurement sites were selected for the indoor ambient environment
measurements consisting primarily of office buildings and factory
installations. These locations were selected as representative of
environments in which E-911 enabled handsets (using enhanced GPS
technology) are anticipated to operate coincident with UWB devices.

A measurement system was designed to measure and record the existing
ambient RF activity at each of the candidate measurement locations. This
system was designed to detect RF emissions down to the very
low-amplitude levels necessary to compare with the conservative GPS
receiver susceptibility threshold assumed in the derivation of the UWB
emissions limits. The measurement system was transported to an
assortment of locations where existing ambient RF emissions were
measured and recorded for subsequent analysis.

The measurement results show that the GPS L1 and L2 frequency bands are
quiet with respect to existing ambient emissions at those outdoor
locations where tests were conducted. However, the data also reveals
that in at least some locations, particularly indoor locations similar
to those assumed in the derivation of the UWB emission limits, the
ambient noise environment, rather than the GPS receiver thermal noise
density, may actually be the limitation to the reception of the
low-amplitude GPS signals.

The measurement system developed for the ambient tests was also used at
the FCC Laboratory facility to measure and record radiated emissions and
associated power levels produced in the GPS frequency bands by common
consumer electronic/electrical devices.

These measurement results show that although many of the devices tested
radiate emissions into the GPS frequency bands, the associated
amplitudes were at much lower levels than permitted by the applicable
limits. However, it was also determined that the amplitudes associated
with these emissions were frequently in excess of the limits established
for UWB emissions.

As part of this measurement effort, the ambient noise environment in the
lower ARNS (960-1160 MHZ) frequency band was also examined. This band is
not used to support GPS operations nor is it identified for use in the
GPS modernization plan. Rather this frequency band is used to support
terrestrial-based navigational aids such as the Distance Measuring
Equipment (DME) and the Air Traffic Control Radio Beacon (ATCRBS). NTIA
stated that \"the operational limits required for the protection of the
GPS will also be adequate to protect DME operations.\"[^1] The
measurement results show that the ambient emissions in this band are
generally above the adopted UWB emission limits. Thus it appears that
the limiting factor in this band will also be the ambient noise
environment rather than the limit based on the GPS receiver thermal
noise density. In addition, Table 6 in the NTIA letter shows that a
maximum EIRP of -64 dBm/MHz is required to protect the DME system under
the most conservative assumptions, which is well above both the adopted
UWB limit and the ambient noise environment for this band.\"[^2]

**ACKNOWLEDGEMENTS**

The author would like to recognize the following people for their
contributions in the completion of this effort. Many thanks go to Mr.
Michael Nicolay of the FCC Laboratory for his technical guidance and
efforts in coordinating access to many of the sites at which data was
collected. Mr. David Means of the FCC Laboratory was also instrumental
in coordinating measurement locations for this effort. Thanks go to Mr.
Joe Piekarski of Agilent Technologies for his efforts in providing the
sensitive measurement instrumentation necessitated by this effort.
Finally, thanks to all of those who permitted access to their facilities
in support of the data collection phase of this project.

# SECTION ONE INTRODUCTION

**BACKGROUND**

On February 14, 2002, the Federal Communications Commission (FCC)
adopted the First Report and Order (R&O) authorizing the limited use of
Ultra-Wideband (UWB) devices on an unlicensed basis under Part 15 of the
FCC rules.[^3] UWB devices operate by employing very narrow or
short-duration pulses that result in an extremely wideband frequency
spectra. UWB technology holds great promise for a vast array of new
applications with the potential for providing significant benefits to
public safety operations, as well as business and consumer applications.

The UWB R&O establishes average limits for UWB emissions in the form of
application-based emission masks. In the 960-1610 MHz frequency range,
the emissions limits defined by these masks are predicated on the
protection of current and future Global Positioning System (GPS)
operations

In an effort to determine appropriate UWB emissions limits in those
frequency bands in which GPS operates, the Commission, within the Notice
of Proposed Rulemaking (NPRM), encouraged the undertaking of measurement
efforts to assess the susceptibility of GPS receivers to UWB
emissions.[^4] Several parties performed measurement programs to assess
this interference potential and provided the data and analyses as a part
of the record in this proceeding.[^5]

General agreement was obtained from each of these studies with respect
to the interference susceptibility of GPS receivers to various
categories of UWB emissions (broadband noise, CW, and pulsed). In
addition, the results from these tests were consistent with GPS
protection criteria used by the International Telecommunications
Union-Radiocommunications Sector (ITU-R) and by various aeronautical
standards organizations e.g., International Civil Aviation Organization
(ICAO), Federal Aviation Administration (FAA), RTCA Inc, etc.

NTIA has indicated that additional protection may be required to address
potential interference to emerging GPS receiver technology. Enhanced GPS
is intended for use in providing location information as a solution for
implementing enhanced 911 (E-911) services in mobile telephone handsets.
Since this technology was not available at the time, none of the test
efforts considered the potential for interference from UWB emissions to
this type of GPS receiver.

To protect for this new GPS technology, NTIA proposed an analytically
derived protection criterion based on the thermal noise floor of a
typical GPS receiver. Specifically, NTIA recommended a receiver
susceptibility mask based on constraining undesired UWB emissions to
levels 6 dB below the thermal noise floor of a GPS receiver.[^6] In
addition, NTIA proposed an operational scenario assumed to be
representative of a worst-case interference interaction between a UWB
emitter and a GPS receiver. This scenario was utilized in the
link-budget calculation to determine the maximum UWB emission level
tolerable by this class of GPS receiver. The scenario assumes an
enhanced GPS receiver (activated by placing an E-911 call) and a UWB
device are simultaneously operating with an unobstructed signal
propagation path at a separation distance of two meters.

The Commission recognizes the growing importance of GPS in everyday life
and is committed to ensuring that the GPS signals are not degraded or
interrupted as a result of radio frequency interference. However, the
Commission is also committed to fostering the development and
implementation of promising new radio communications technology. As
such, the Commission must carefully balance the need to protect critical
services like GPS from interference without placing unnecessary burdens
on developing technologies such as UWB. It is in the public interest
that appropriate limits be developed to provide adequate protection but
not overprotect these services, particularly to an extent that overly
encumbers the development of new technologies.

The following statement was included in the text of the R&O: "It is our
belief that the standards contained in this Order are extremely
conservative. These standards may change in the future as we continue to
collect data regarding UWB operations."[^7] This measurement effort
represents a first step in collecting the data necessary to assess these
standards in accordance with the Commission's commitment to re-examine
the UWB rules within six to twelve months of the initial release of the
R&O. Since very few UWB devices had actually reached the marketplace at
the time this effort was initiated, it was decided that this first step
assessment would focus on an evaluation of some of the assumptions that
were integral to the derivation of the emission limits for UWB devices.
In particular, this effort concentrates on an examination of
pre-existing emissions and associated amplitude (power density) levels
present in those frequency bands that were identified as requiring
extreme protection from UWB operations.

**OBJECTIVE**

The objective of this effort is to acquire and analyze the data
necessary to assess existing radio frequency emissions and associated
power density levels within specific frequency bands in the 960-1610 MHz
portion of the electromagnetic spectrum.

**APPROACH**

Since the UWB emission limits in the 960-1610 MHz band are based on
protection of GPS receivers to levels below their thermal noise floor,
an obvious question is "will a GPS receiver realize its thermal noise
floor in existing electromagnetic environments?" A secondary question
that arises as a result of the small separation distance assumed in the
derivation is "what emission levels are currently produced within the
GPS frequency bands by common electronic and electrical devices at a
distance of two meters?" In an effort to address these questions, the
FCC Laboratory examined existing RF emission levels within those
frequency bands over which the GPS interference susceptibility mask was
applied in the derivation of the UWB emission limits.

In order to address the first question, a measurement approach was
developed to determine the existing level of ambient RF activity within
these specific frequency bands. A set of locations was identified from
which to perform the measurement of existing ambient RF activity based
on the likelihood of UWB-to-GPS interactions. These locations are
divided into two distinct categories; outdoor locations and indoor
locations. The outdoor sites identified for performing these
measurements include airports, seaports, train yards, and industrial
sites. These sites were selected primarily because GPS has been cited as
a key navigational component for use in aviation, maritime, rail, and
automotive transportation systems.

The measurement sites selected for the indoor ambient environment
measurements include office buildings and factory installations. These
locations were selected as representative of those environments in which
enhanced GPS would be anticipated to operate in E-911 applications
coincident with UWB operations.

A measurement system was designed to measure and record the existing
ambient RF activity at each of the candidate measurement locations. This
system was designed to detect RF emission levels down to the very low
amplitudes necessary to facilitate a comparison to the conservative GPS
receiver susceptibility threshold used in the derivation of the UWB
emissions limit. The measurement system was transported to an assortment
of locations where existing ambient RF emissions were measured and
recorded for subsequent analysis.

To address the second question, a measurement system was developed
capable of detecting radiated emissions from existing
electronic/electrical devices down to levels equivalent to the UWB
emission limit. This measurement system was used at the FCC Laboratory
facility to measure and record spurious emissions and associated power
levels produced by these types of devices in the frequency bands of
interest.

Subsequent to the data collection portion of this effort, an analysis
was performed for each data set. Comments are provided with regard to
any identifiable trends observed within the data sets.

**SECTION TWO**

**DESCRIPTION AND USE OF THE FREQUENCY BANDS EXAMINED**

**GPS APPLICATIONS**

The Global Positioning System is an integral component in a wide range
of position determination and timing applications worldwide. GPS has
become an essential element in aviation and maritime navigation systems
and is also routinely being implemented in navigational systems used by
trains, automobiles, and many other transportation and vehicular
applications. The telecommunications, banking, and power distribution
industries have become reliant on the ability of GPS to provide very
precise timing information necessary for managing capacity and
distribution of their services.

Since a major consideration in the derivation of the UWB limits
applicable to the 960-1610 MHz was the protection of GPS receivers (both
existing and future implementations), this effort was limited to an
assessment of the existing RF activity in those frequency bands in which
GPS either currently operates or plans to operate in the future.
Additionally, since the UWB emission limit, although predicated on the
protection of GPS receivers, is also applied to spectrum that is not
currently used or planned for use in GPS operations, it was determined
that these particular band segments should also be examined.
Specifically, the lower Aeronautical Radio Navigation Service (ARNS)
band between 960 and 1160 MHz was selected for examination in addition
to the three GPS frequency bands. The following paragraphs briefly
discuss characteristics associated with each of the frequency bands
examined within this measurement effort.

**GPS L1 FREQUENCY BAND**

The GPS L1 frequency band is contained within the 1559-1610 MHz
restricted band of operation. The 1559-1610 MHz band is allocated on a
co-primary basis to the Aeronautical Radio Navigation Service (ARNS) and
the Radio Navigation Satellite Service (RNSS). The upper portion of the
band is used to host downlinks (space-to-Earth) from the Russian GLONASS
satellite navigation system. The European Union is finalizing plans to
build and launch a new satellite radio navigation system, called
Galileo, which will also provide one or more downlink signals within
this band.

The GPS L1 signal is transmitted from the orbiting GPS satellites on a
center frequency of 1575.42 MHz. The total bandwidth registered to the
GPS L1 signal is 24 MHz (i.e., 1575.42 ± 12 MHz); however, typical GPS
receivers process only 2-12 MHz of the signal. The L1 signal provides a
Standard Positioning Service (SPS), a Precise Positioning Service (PPS),
and a navigation message. The L1 carrier is modulated with a coarse
acquisition (C/A) code to provide the SPS and is the only signal
presently guaranteed to be available to civil users of GPS. The L1
carrier is also modulated with a longer precision (P) code, in phase
quadrature with the C/A-code, to provide the PPS. This service is
available to those users who require greater precision, with the use of
specialized GPS receivers, but is subject to being made unavailable to
civil users at any time by modulation with the encrypted Y-code.

The FAA and other international aeronautical administrations are
planning to launch geo-stationary orbiting satellites to augment the GPS
constellation. This is being done to provide the satellite availability
required to certify GPS for use as a sole-means of aeronautical radio
navigation. The domestic augmentation system is known as the Wide Area
Augmentation System (WAAS). Similar systems are also being planned in
Europe and Japan. Additionally, the FAA is planning to locally augment
GPS at select airports with a system know as the Local Area Augmentation
System (LAAS). This system will consist of terrestrial-based
transmitters to augment the space-based GPS signal for use in the
precision landing of aircraft. Both of these systems are planned for
operation in the GPS L1 frequency band.

As a result of the GPS signals originating from a distant point in space
(approximately 20,000 km), the signal levels are very low when they
reach a terrestrial user. The minimum guaranteed GPS signal power
specification for the C/A-code is -130 dBm into a 0 dBic gain
antenna;[^8] however, the actual signal levels are known to be 7-10 dB
greater than the minimum level. Nonetheless, the signals are very weak
and necessitate the use of signal processing techniques in order to
recover a usable signal. The GPS signal strength can be further reduced
before arriving at a user receiver from signal attenuation associated
with foliage, terrain and/or building shielding.

Because the GPS L1 band is within a restricted band of operation that is
currently used exclusively for radio navigation satellite downlinks,
there are no authorized frequency assignments to terrestrial-based
systems. Therefore it is hypothesized that any existing emissions in the
GPS L1 band will be a result of spurious (out-of-band and/or harmonic)
emissions from intentional radiators, and/or low-level unintentional or
incidental emissions from electronic and electrical devices (i.e., no
fundamental emissions are expected to be observed).

**GPS L2 FREQUENCY BAND**

The GPS L2 signal is contained within the 1215-1240 MHz restricted band
of operation, which is allocated on a co-primary basis to the
Radiolocation Service and the RNSS. In addition to the L2 signal, this
frequency band hosts the Joint Surveillance System (JSS) radar system,
shared by the Department of Defense (DoD) and the FAA. These radar
systems, in particular the Air Route Surveillance Radars (ARSRs), are
used by the FAA for en-route surveillance of commercial aircraft and by
the DoD for early warning air defense. To accommodate the relatively
weak GPS signal, the radar systems operating in the band avoid frequency
assignments on the L2 center frequency.

The GPS L2 signal is transmitted on a center frequency of 1227.60 MHz.
The registered bandwidth of the GPS L2 signal is also 24 MHz (1227.60 ±
12 MHz). Currently, only the P-code (unencrypted) or Y-code (encrypted)
is modulated onto the GPS L2 carrier.

Ongoing GPS modernization efforts include the addition of a new civil
signal to the GPS L2 carrier providing an additional channel for
utilization of the SPS.[^9] This new signal will be implemented by
modulating a C/A-code in phase-quadrature with the existing P- or
Y-code, similar to the structure of GPS L1.

**GPS L5 FREQUENCY BAND**

The implementation of a GPS L5 signal is also part of the ongoing GPS
modernization effort. At the most recent World Radio Conference
(WRC-2000) an allocation to RNSS was adopted in the 1164-1215 MHz
segment of the 960-1215 MHz ARNS frequency band. The 1164-1188 MHz
segment will be used to host a new GPS aviation-specific signal. The new
signal is denoted L5 and will be transmitted on 1176.45 MHz with a
registered bandwidth of 24 MHz (1176.45 ± 12 MHz).[^10] The upper
segment (1188-1215 MHz) will be used to host a Galileo downlink signal.
The new GPS L5 signal has been specifically designed to support aviation
applications and will improve on known shortcomings of the existing L1
signal. As a result, the L5 signal is anticipated to be a more robust
signal (e.g., 6 dB higher power, longer code, etc.) and less susceptible
to both noise-like and spectral line interference than the existing L1
signal.

**ARNS FREQUENCY BAND**

Prior to WRC-2000, the 960-1215 MHz band was allocated exclusively to
the ARNS. Traditionally, this band has been used to support navigational
aids such as the FAA's Distance Measuring Equipment (DME) and the
military Tactical Aeronautical Navigation (TACAN) systems. The FAA also
operates the Air Traffic Control Radio Beacon System (ATCRBS) on two
discrete frequencies (1030 and 1090 MHz) within this band. In addition,
the military Joint Tactical Information Distribution System (JTIDS)
operates in this frequency band. At WRC-2000, a co-primary allocation
was granted to RNSS in the 1164-1215 MHz portion of the band as
discussed above. In this measurement effort, the 960-1164 MHz portion of
the band is also of interest, particularly since the UWB emission limit,
although based on the protection of GPS receivers, is applied, although
GPS does not currently utilize nor has plans to utilize this part of the
spectrum.

**SECTION THREE**

**DERIVATION OF THE UWB EMISSION LIMIT**

In this section, the methodology and assumptions that were incorporated
in the derivation of the emission limits applicable to UWB devices
operating over the 960-1610 MHz region of the electromagnetic spectrum
will be presented and discussed. In this measurement effort, elements of
this derivation, particularly the GPS receiver susceptibility threshold,
are used as a basis for comparison to existing ambient and spurious
emission levels.

As previously stated, the derived UWB limits applicable in the 960-1610
MHz frequency band are predicated on the protection GPS receivers from
harmful interference. Several parties to the UWB rulemaking performed
measurements of GPS receiver susceptibility to UWB emissions. General
agreement was observed in the results from each of these test efforts.
Additionally, these results were shown to be consistent with GPS
interference protection criteria developed by the United States
delegation to WRC-2000 within the ITU-R[^11] and by RTCA[^12] for use in
performing GPS interference analyses. The threshold for broadband noise
interference developed within these groups is based on maintaining a
minimum GPS carrier-to-noise density (C/N~0~) of 34 dB-Hz, necessary for
satellite acquisition (a 30 dB-Hz C/N~0~ is required to maintain
tracking of an already acquired satellite), assuming the minimum
specified GPS signal strength of -130 dBm.[^13] The broadband noise
interference criterion defined in these documents is

-110.5 dBm/MHz. This criterion was developed for an aviation scenario
that assumes a GPS receive antenna gain of -4.5 dBi. When adjusted for
use in land-based GPS analyses (i.e., the undesired emitter is
constrained to a hemispherical volume with respect to the GPS receiver
resulting in a minimum GPS antenna gain of 0 dBi), the equivalent
threshold is -106 dBm/MHz.

In the measurement effort undertaken by NTIA to assess the interference
susceptibility of GPS receivers to UWB emissions, the broadband noise
interference threshold was determined to range between -106 and -100
dBm/MHz when the interference metric considered was satellite
break-lock. When the interference metric considered was a degradation in
reacquisition time the interference threshold ranged between -106 and
-104.5 dBm/MHz.[^14] Regardless of the interference metric assumed, the
most conservative threshold determined from the NTIA measurements was

-106 dBm/MHz, the same threshold as determined by RTCA and ITU. In the
initial NTIA analyses, the interference susceptibility threshold used to
perform the link budgets was consistent with their measured data.[^15]

NTIA has indicated that additional protection may be required to address
potential interference to an emerging GPS receiver technology. This
technology, enhanced GPS, is intended for use in providing location
information as a solution for implementing enhanced 911 (E-911) services
in mobile telephone handsets. Since this technology was not available at
the time, none of the test efforts considered the potential for
interference from UWB emissions to this type of GPS receiver. Thus, NTIA
proposed an analytically derived protection criteria based on the
thermal noise floor of a typical GPS receiver. Specifically, NTIA
requested a receiver susceptibility threshold based on constraining
undesired UWB emissions to levels 6 dB below the thermal noise floor of
a GPS receiver (I/N ≤ -6 dB).[^16] This requirement was said to be
necessary to protect the indoor use of GPS where the available C/N~0~
may be 20 dB or less, possibly even as low as 10 dB[^17]. Presumably,
this 14-24 dB reduction in the available GPS C/N~0~ inside of a building
is due solely to building attenuation, since the receiver noise density
is assumed constant.

The thermal noise floor of a GPS receiver is determined from:

> N~0~ = 10 log (kTB) + NF (1)

where,

N~0~ = thermal noise floor of a typical GPS receiver, dBW/Hz,

k = Boltzmans constant = 1.38 x 10^-23^ watts/Hz,

T = system temperature = 290 K,

B = receiver bandwidth = 1 x 10^6^ Hz, and

NF = receiver noise figure = 2.5 dB (typical).

Applying Equation 1 and converting to units of dBm/MHz, the thermal
noise floor of a typical GPS receiver was determined to be --111.5
dBm/MHz. Therefore, the UWB power received by a GPS receiver must be
limited to --117.5 dBm/MHz (6 dB below the thermal noise floor).

In all subsequent link budget analyses, a receiver susceptibility
threshold of

-117.5 dBm/MHz was used to determine the UWB limits in the 960-1610 MHz
frequency range.[^18]^,^[^19] Additionally, NTIA recommended that an
operational scenario, said to be representative of a worst-case
interference interaction between a UWB emitter and an enhanced GPS
receiver, be used in performing the link-budget calculation to determine
the maximum level of UWB emissions tolerable to this class of GPS
receiver. This scenario assumes an enhanced GPS receiver (activated by
placing an E-911 call) and a UWB device are simultaneously operating
with an unobstructed signal propagation path at a separation distance of
two meters[^20].

Under these assumptions, the link budget for indoor UWB applications is:

+---------------------------------------------+------------------------+
| **Parameter**                               | **Value**              |
+---------------------------------------------+------------------------+
| Receiver Susceptibility Mask (dBm/MHz)      | -117.5                 |
|                                             |                        |
| (Broadband Noise)                           |                        |
+---------------------------------------------+------------------------+
| GPS Antenna Gain in Direction of RFI Source | 0                      |
| (dBi)                                       |                        |
+---------------------------------------------+------------------------+
| Propagation Loss (dB)                       | 42.2                   |
|                                             |                        |
| (Minimum Distance Separation (meters))      | \(2\)                  |
+---------------------------------------------+------------------------+
| Noise-Like RFI Emission Limit (dBm/MHz)     | -75.3                  |
+---------------------------------------------+------------------------+
| 47 C.F.R.§15.209 Emission Limit (dBm/MHz)   | -41.3                  |
+---------------------------------------------+------------------------+
| Additional Attenuation Required (dB)        | 34.0                   |
+---------------------------------------------+------------------------+

Thus, the average emission limit applicable indoor UWB devices in the
960-1610 MHz frequency range is an equivalent isotropic radiated power
(EIRP) of

-75.3 dBm/MHz. This limit is applicable in the 960-1610 MHz band to the
following UWB applications: Indoor UWB Applications (Section 15.517),
Handheld UWB Applications (Section 15.519), and Vehicular Radar Systems
(Section 15.515 ).

In this measurement effort, the GPS interference susceptibility
threshold,

-117.5 dBm/MHz, is used as a basis for comparison in both the ambient
and spurious emissions measurements. A display line is used to depict
this limit on the spectrum analyzer plots included in this report.

For the ambient emission measurements, the display line at --117.5
dBm/MHz is used as the basis for comparison to the measured ambient
power levels. Since the source of the ambient emissions is not always
known, the distance between the source and the measurement antenna
cannot be determined. Thus, an EIRP cannot be calculated to compare
directly to the UWB limits as they are defined in the rules. However,
since the limits were derived based on a GPS receiver susceptibility
threshold of

-117.5 dBm/MHz, a comparison to this level is equivalent to a comparison
with the emission limit. The underlying assumption is that the measured
ambient emissions directly correspond to what would be detected by a GPS
receiver at the same location as the measurement system antenna.

For the spurious radiated emission measurements, the display line value

(-117.5 dBm/MHz) directly represents the UWB emission limit of --75.1
dBm/MHz (EIRP), when measured at a distance of 2 meters within a 1 MHz
measurement bandwidth.

#### SECTION FOUR

**MEASUREMENT SYSTEM AND PROCEDURES**

## MEASUREMENT SYSTEM DESCRIPTION

The measurement system used to acquire the data in this effort is shown
in

Figure 4-1 below.

![](media/image1.wmf){width="6.0in"
height="3.5229166666666667in"}**Figure 4-1. Measurement System Block
Diagram.**

An Agilent model E4440 PSA spectrum analyzer was the primary measurement
instrument used to collect the data in this effort. This analyzer
incorporates a true RMS detector providing a means to acquire, display,
and store a continuous trace of RMS average power levels across the
frequency bands under examination.

A pair of low noise amplifiers (LNAs) was cascaded to enable the
detection of emissions to the very low levels necessary to compare with
the UWB limit. Two different measurement systems were used over the
duration of this effort, differing only by the first stage LNA employed.
Measurement system A utilized an octave-tuned (1-2 GHz), pre-amplifier
with a very low noise figure (NF) of 0.6 dB. Measurement system B also
utilized an octave tuned (1-2 GHz) pre-amplifier but with a NF equal to
1.0 dB. In both systems, the first stage amplifier effectively
establishes the noise figure of the entire measurement system. The
second stage amplifier is a broadband amplifier of the type typically
used in a compliance measurement set-up. A 10-dB attenuator was inserted
between the two LNAs to provide isolation.

A tunable band-pass filter (BPF) was included in the measurement system
ahead of the first stage LNA to filter out signals originating outside
of the frequency band under examination.

The measurement antenna was a double-ridge broadband horn calibrated for
use in the 1-12 GHz frequency range. This type of antenna was determined
to provide the greatest flexibility with respect to polarization and
broadband frequency characteristics, while also producing sufficient
gain to accommodate the measurement of emissions to the low levels
necessary to compare to the UWB limits. It should be noted that
normalizing the data collected with this antenna to equate to a GPS
antenna can result in an under estimate of the ambient levels that would
actually be seen by a GPS receiver, particularly when the emission
source is located outside the main beam of the measurement antenna.

Specific information for each component of the measurement system and
the equipment used for calibration is presented below in Table 4-1.

**TABLE 4-1. Test and Calibration Equipment Specifications.**

+-----------------------+-----------------------+-----------------------+
| **EQUIPMENT**         | **MANUFACTURER and    | **RELEVANT            |
|                       | MODEL**               | SPECIFICATIONS**      |
+-----------------------+-----------------------+-----------------------+
| Spectrum Analyzer     | Agilent               | 3 Hz to 26.5 GHz      |
|                       |                       |                       |
|                       | E4440A                |                       |
+-----------------------+-----------------------+-----------------------+
| Signal Generator      | Agilent               | 250 kHz to 4 GHz      |
|                       |                       |                       |
|                       | E4437B                |                       |
+-----------------------+-----------------------+-----------------------+
| LNA 2                 | Hewlett-Packard       | 0.5-26.5 GHz          |
|                       | HP83017A              |                       |
|                       |                       | Gain = 25 dB (Min)    |
|                       |                       |                       |
|                       |                       | NF = 8 dB (Max)       |
+-----------------------+-----------------------+-----------------------+
| LNA 1 (System A)      | MITEQ                 | 1.0-2.0 GHz           |
|                       |                       |                       |
|                       | A                     | Gain = 45 dB (Min)    |
|                       | FS3-01000200-06-10P-6 |                       |
|                       |                       | NF = 0.6 dB (Max)     |
+-----------------------+-----------------------+-----------------------+
| LNA 1 (System B)      | MITEQ                 | 1.0-2.0 GHz           |
|                       |                       |                       |
|                       | AMF-3B-010020-10-25P  | Gain = 42 dB (Min)    |
|                       |                       |                       |
|                       |                       | NF = 1.0 dB (Max)     |
+-----------------------+-----------------------+-----------------------+
| Tunable Band Pass     | Texscan               | 0.75-1.5 GHz          |
| Filter                |                       |                       |
|                       | 5VF750/1000-5AA       |                       |
+-----------------------+-----------------------+-----------------------+
| Receive Antenna       | EMCO 3105             | 1.0-12.0 GHz          |
|                       |                       |                       |
|                       | Double Ridge Guide    |                       |
|                       | Horn                  |                       |
+-----------------------+-----------------------+-----------------------+

## 

## MEASUREMENT SYSTEM CALIBRATION 

The data obtained from the calibration of the measurement system
components between the spectrum analyzer and the measurement antenna is
presented in APPENDIX A. The following tables summarize the data
relevant to characterizing the measurement system.

Tables 4-2 and 4-3 summarize the external gain as measured at the center
of each of the frequency bands under examination for each of the two
measurement systems used in this effort. The external gain reported in
the tables is the sum of the cascaded LNA gains less the attenuation in
the coaxial cables, connectors and the isolation pad, and the insertion
loss of the band pass filter.

TABLE 4-2. Measurement System External Gain (System A).

+---------------------------------+------------------------------------+
| **CENTER**                      | #                                  |
|                                 |  MEASUREMENT SYSTEM EXTERNAL GAIN  |
| **FREQUENCY**                   |                                    |
|                                 | **(dB)**                           |
| **(MHz)**                       |                                    |
+---------------------------------+------------------------------------+
| 1575.4                          | 64.8                               |
+---------------------------------+------------------------------------+
| 1227.6                          | 66.7                               |
+---------------------------------+------------------------------------+
| 1176.0                          | 66.4                               |
+---------------------------------+------------------------------------+
| 985.0                           | 68.0                               |
+---------------------------------+------------------------------------+
| 1035.0                          | 67.7                               |
+---------------------------------+------------------------------------+
| 1085.0                          | 67.3                               |
+---------------------------------+------------------------------------+
| 1135.0                          | 67.0                               |
+---------------------------------+------------------------------------+

TABLE 4-3. Measurement System External Gain (System B).

+---------------------------------+------------------------------------+
| **CENTER**                      | #                                  |
|                                 |  MEASUREMENT SYSTEM EXTERNAL GAIN  |
| **FREQUENCY**                   |                                    |
|                                 | **(dB)**                           |
| **(MHz)**                       |                                    |
+---------------------------------+------------------------------------+
| 1575.4                          | 63.5                               |
+---------------------------------+------------------------------------+
| 1227.6                          | 64.7                               |
+---------------------------------+------------------------------------+
| 1176.0                          | 64.9                               |
+---------------------------------+------------------------------------+
| 985.0                           | 67.4                               |
+---------------------------------+------------------------------------+
| 1035.0                          | 66.7                               |
+---------------------------------+------------------------------------+
| 1085.0                          | 66.6                               |
+---------------------------------+------------------------------------+
| 1135.0                          | 66.2                               |
+---------------------------------+------------------------------------+

## MEASUREMENT ANTENNA CALIBRATION

TABLE 4-4 lists the calibrated antenna gain provided by the manufacturer
of the double-ridge guide horn antenna used in the measurement system.

TABLE 4-4. Measurement Antenna Gain.

+---------------------------------+------------------------------------+
| **FREQUENCY**                   | **ANTENNA GAIN**                   |
|                                 |                                    |
| **(MHz)**                       | **(dBi)**                          |
+---------------------------------+------------------------------------+
| 1575.4                          | 8.6                                |
+---------------------------------+------------------------------------+
| 1227.6                          | 7.2                                |
+---------------------------------+------------------------------------+
| 1176.0                          | 7.1                                |
+---------------------------------+------------------------------------+
| 985.0                           | 6.1                                |
+---------------------------------+------------------------------------+
| 1035.0                          | 6.4                                |
+---------------------------------+------------------------------------+
| 1085.0                          | 6.7                                |
+---------------------------------+------------------------------------+
| 1135.0                          | 6.9                                |
+---------------------------------+------------------------------------+

**OVERALL MEASUREMENT SYSTEM GAIN**

In order to determine the true amplitude of the signals impinging on the
measurement antenna, adjustments to the displayed amplitude levels are
necessary to account for the amplification in the measurement system,
external to the spectrum analyzer. This amplification is necessary to
detect low-amplitude signals but must be removed from the data to reveal
the true signal level. The spectrum analyzer used in these measurements
provides the capability to perform these corrections internally, but the
user must enter the applicable gain values in order to adjust the data.

Tables 4-5 and 4-6 list the gain values determined for measurement
systems A and B, respectively. The overall system gain reported in these
tables are the values that were input to the spectrum analyzer to
facilitate the internal correction to the data so that the displayed
amplitudes accurately depict the actual signal levels impinging on the
measurement antenna. The overall system gain was determined by adding
the measurement system external gain of each of the measurement systems
and the antenna gain for each frequency range examined as a part of this
effort.

**TABLE 4-5. Total System Gain (System A).**

+---------------+------------------+-----------------+-----------------+
| **FREQUENCY** | **EXTERNAL       | **ANTENNA       | **OVERALL       |
|               | GAIN**           | GAIN**          | SYSTEM GAIN**   |
| **(MHz)**     |                  |                 |                 |
|               | **(dB)**         | **(dBi)**       | **(dB)**        |
+---------------+------------------+-----------------+-----------------+
| 1575.4        | 64.8             | 8.6             | 73.4            |
+---------------+------------------+-----------------+-----------------+
| 1227.6        | 66.7             | 7.2             | 73.9            |
+---------------+------------------+-----------------+-----------------+
| 1176.0        | 66.4             | 7.1             | 73.5            |
+---------------+------------------+-----------------+-----------------+
| 985.0         | 68.0             | 6.1             | 74.1            |
+---------------+------------------+-----------------+-----------------+
| 1035.0        | 67.7             | 6.4             | 74.1            |
+---------------+------------------+-----------------+-----------------+
| 1085.0        | 67.3             | 6.7             | 74.0            |
+---------------+------------------+-----------------+-----------------+
| 1135.0        | 67.0             | 6.9             | 73.9            |
+---------------+------------------+-----------------+-----------------+

**TABLE 4-6. Total System Gain (System B).**

+-----------------+-----------------+-----------------+-----------------+
| **FREQUENCY**   | **SYSTEM GAIN** | **ANTENNA       | **OVERALL       |
|                 |                 | GAIN**          | SYSTEM GAIN**   |
| **(MHz)**       | **(dB)**        |                 |                 |
|                 |                 | **(dBi)**       | **(dB)**        |
+-----------------+-----------------+-----------------+-----------------+
| 1575.4          | 63.5            | 8.6             | 72.1            |
+-----------------+-----------------+-----------------+-----------------+
| 1227.6          | 64.7            | 7.2             | 71.9            |
+-----------------+-----------------+-----------------+-----------------+
| 1176.0          | 64.9            | 7.1             | 72.0            |
+-----------------+-----------------+-----------------+-----------------+
| 985.0           | 67.4            | 6.1             | 73.5            |
+-----------------+-----------------+-----------------+-----------------+
| 1035.0          | 66.7            | 6.4             | 73.1            |
+-----------------+-----------------+-----------------+-----------------+
| 1085.0          | 66.6            | 6.7             | 73.3            |
+-----------------+-----------------+-----------------+-----------------+
| 1135.0          | 66.2            | 6.9             | 73.1            |
+-----------------+-----------------+-----------------+-----------------+

**MEASUREMENT PROCEDURES**

The procedures implemented for measuring both existing ambient emissions
and spurious emissions from consumer devices are defined in Appendix B
of this document.

**SECTION FIVE**

**MEASURED DATA**

### AMBIENT EMISSIONS MEASUREMENTS

Field surveys were performed at those locations deemed consistent with
the list of candidate sites, i.e., airports, shipyards, train yards,
industrial areas (outdoor sites), office buildings and factory floors
(indoor sites). These surveys were performed to determine the presence
of existing ambient emissions and the associated power levels within the
frequency bands under examination.

These measurements were intended to determine the amplitude of existing
ambient emissions as would be experienced at the measurement location by
a GPS receiver. The measured levels were then compared to the
theoretical GPS interference criterion supported by NTIA and used in
establishing the emission limit applicable to UWB devices. To facilitate
this comparison the measurement system was configured to simulate the RF
front-end of a GPS receiver. The resolution bandwidth of the measurement
receiver (spectrum analyzer) was set to 1 MHz, the same as the RF
bandwidth of many GPS receivers and also to give results in dBm/MHz,
consistent with the specified interference threshold units. The spectrum
analyzer was tuned to the center frequency in each of the GPS frequency
bands, as would a GPS receiver, but was also used to span the entire
registered bandwidth of the GPS signal. The ambient emissions were
measured in terms of RMS average, consistent with the results of studies
performed by NTIA and others showing that GPS receivers are most
susceptible to average power interference. Conventional GPS receivers
employ an integration time on the order of

20 milliseconds; however, enhanced GPS receivers, for which the extreme
protection criteria was deemed necessary, were said to "...integrate the
satellite signal over a longer time period, allowing the receiver to
obtain a 20 to 30 dB higher processing gain than a conventional GPS
receiver."[^21] For these measurements, an effective integration time of
100 milliseconds was utilized in performing the RMS averaging
(one-hundred 1-msec sweeps). The primary distinction between the
measurement system and the RF chain of a GPS receiver was the receive
antenna. The measurement system utilized an antenna that is more
directional than a GPS antenna in order to provide sufficient gain to
accommodate measurements to the extremely low levels necessary to
compare to the UWB emission limits (i.e., below thermal noise). The data
is adjusted to equate to the

0-dBi gain assumed for a GPS antenna in the UWB-to-GPS receiver
interaction link budget analyses of UWB interference potential. It is
noted that this normalization of the antenna gain can lead to an
underestimate of the measured ambient signal amplitudes, particularly
when the emission source(s) are located outside of the measurement
antenna main beam.

In these ambient measurements no concerted effort was made to identify
the source of the emissions observed. Such efforts would be very
difficult, particularly since many of the emissions present in these
frequency bands are likely to be spurious, rather than fundamental
emissions. Therefore, since neither the emission source nor its physical
location is known, it is not possible to determine the EIRP relative to
the source emitter(s). Thus, an EIRP cannot be calculated that could be
compared directly to the UWB limits as they are defined in the rules.
However, since the limits were derived based on a GPS receiver
susceptibility threshold of -117.5 dBm/MHz, a comparison to this level
represents an equivalent metric. The underlying assumption is that the
measured ambient emissions directly correspond to what would be detected
by a GPS receiver at the same location as the measurement system
antenna. Thus, any emissions in excess of the susceptibility threshold
would be expected to degrade the performance of those GPS receivers
considered in the link budget analyses.

## 

## Ambient Emissions Measurement Locations

Table 5-1 provides a list of the outdoor locations where the ambient
emissions measurements were performed as a part of this effort. Table
5-2 lists the indoor locations where ambient emissions measurements were
performed.

**Table 5-1.** **Outdoor Ambient Emissions Measurement Sites.**

+-------------------------+------------------------+-------------------+
| **SITE**                | **DESCRIPTION**        | **COORDINATES**   |
+-------------------------+------------------------+-------------------+
| BWI Airport             | Aircraft Observation   | 39º 09.771' N     |
|                         | Area                   |                   |
|                         |                        | 076º 39.815' W    |
+-------------------------+------------------------+-------------------+
| Dulles International    | Paige General Aviation | 38º 57.170' N     |
| Airport                 | Terminal               |                   |
|                         |                        | 077º 26.638' W    |
+-------------------------+------------------------+-------------------+
| Reagan National Airport | General Aviation       | 38º 50.748' N     |
|                         | Parking Lot            |                   |
|                         |                        | 077º 02.668' W    |
+-------------------------+------------------------+-------------------+
| Port of Baltimore       | Security Office        | 39º 15.083' W     |
|                         | Parking Lot            |                   |
|                         |                        | 076º 33.415' W    |
+-------------------------+------------------------+-------------------+
| U.S. Coast Guard Yard   | Buoy Maintenance       | 39º 12.027'N      |
|                         | Facility               |                   |
|                         |                        | 076º 34.370'W     |
+-------------------------+------------------------+-------------------+
| Train Yard              | AMTRAK Maintenance     | 38º 55.055'N      |
|                         | Facility               |                   |
|                         |                        | 076º 59.286'W     |
+-------------------------+------------------------+-------------------+
| Industrial Location     | Tyson's Corner, VA     | 38º 55.326'N      |
|                         |                        |                   |
|                         |                        | 077º 14.008'W     |
+-------------------------+------------------------+-------------------+

**Table 5-2.** **Indoor Ambient Emissions Measurement Sites.**

+----------------------+----------------------------+-----------------+
| **SITE**             | **DESCRIPTION**            | **COORDINATES** |
+----------------------+----------------------------+-----------------+
| Office Building #1   | Debt Consolidation Firm    | 39º 11.547' N   |
|                      |                            |                 |
|                      | Workspace Area             | 076º 49.014' W  |
+----------------------+----------------------------+-----------------+
| Office Building #2   | FCC Portals                | 38º 52.967' W   |
|                      |                            |                 |
|                      | Large LAN Server Room      | 077º 01.578' W  |
+----------------------+----------------------------+-----------------+
| Office Building #3   | Scientific Research        | 38º 55.326' N   |
|                      | Facility                   |                 |
|                      |                            | 077º 14.008' W  |
|                      | Central Corridor           |                 |
+----------------------+----------------------------+-----------------+
| Office Building #4   | Engineering Research       | 38º 47.917' N   |
|                      | Company Small LAN Sever    |                 |
|                      | Room                       | 077º 11.480' W  |
+----------------------+----------------------------+-----------------+
| Office Building #5   | Engineering Research       | 38º 47.917' N   |
|                      | Company Typical Office     |                 |
|                      | Work Space                 | 077º 11.480' W  |
+----------------------+----------------------------+-----------------+
| Factory Location #1  | Electro-Optics             | 39º 10.948' N   |
|                      | Manufacturer               |                 |
|                      |                            | 076º 48.767' W  |
|                      | Factory Floor              |                 |
+----------------------+----------------------------+-----------------+
| Factory Location #2  | Compact Disc (CD)          | 39º 10.686' N   |
|                      | Manufacturer               |                 |
|                      |                            | 077º 15.047' W  |
|                      | Factory Floor              |                 |
+----------------------+----------------------------+-----------------+
| Factory Location #3  | Automotive Assembly Plant  | 39º 16.024' N   |
|                      |                            |                 |
|                      | Factory Floor              | 076º 32.695' W  |
+----------------------+----------------------------+-----------------+

## 

## Ambient Emissions Measurement Data

The spectrum analyzer plots depicting the data collected at each
measurement site are presented in Appendices C (outdoor sites) and D
(indoor sites).

A sample spectrum analyzer plot is presented below as an aid in
providing an explanation of how to read and interpret the data presented
in the appendices. In these plots, the upper (yellow) trace depicts the
ambient emissions measured in the subject frequency band using a peak
detector and the maximum hold function (i.e., no averaging employed)
over a fifteen-minute period. This trace was generated mainly as a tool
for orienting the measurement antenna and for determining the maximum
likely emission amplitudes to facilitate decisions pertaining to the
necessity of adding additional attenuation in the measurement system so
as to prevent overdriving of components. This data was not used for any
analytical purposes. The lower (blue) trace represents the measured RMS
average emission level over one hundred one-millisecond analyzer sweeps
across the measurement band. This is the data used to compare to the
assumed interference threshold for enhanced GPS receivers. The constant
display line (green) at -117.5 dBm is used as the basis for comparing
the measured data to the theoretical enhanced GPS interference
threshold.

All external measurement system parameters (e.g., amplifier gains, cable
loss, and antenna gain) are accounted for in the spectrum analyzer
display and are provided on each plot under the tag Ext PG located at
the top of the display. At some measurement locations, it was necessary
to add additional attenuation in the measurement system due to the
presence of relatively high-amplitude signals. In those cases where
additional external attenuation was required, the Ext PG value was
adjusted accordingly. Thus, the levels shown on the amplitude axis of
the spectrum analyzer plots represent the actual RMS average power as
measured in a 1 MHz bandwidth at the measurement system antenna.

![](media/image2.png){width="6.0in" height="4.0in"}

Figure 5-1. Sample Spectrum Analyzer Plot from Ambient Emissions
Measurement.

In these plots, the horizontal axis represents frequency and the
vertical axis represents amplitude. For measurements in the GPS
frequency bands, a span of 25 MHz was used to encompass the 24 MHz
registered frequency band. For a 25 MHz span, each vertical graticule
line represents a 2.5 MHz deviation in frequency (25 MHz/10 graticule
lines). For example, in the sample plot of Figure 5-1, the center
vertical graticule line represents the center frequency of 1575.42 MHz.
Each vertical graticule line to the left of the center represents a
decrement from the center frequency of 2.5 MHz and each graticule line
to the right of the centerline represents a 2.5 MHz increment relative
to the center frequency. For the measurements performed in the 960-1160
MHz (ARNS) band, a span of 50 MHz was used, the maximum that could be
achieved within the pass band of the pre-select filter. In these plots,
each vertical graticule line represents a frequency deviation of 5 MHz
(50 MHz/10 graticule lines).

On the amplitude axis, each horizontal graticule line represents a 10 dB
decrement from the reference level amplitude shown in the upper
left-hand corner of the plot. As an example, to determine the maximum
amplitude level from the RMS average trace, begin with the reference
level amplitude of -45 dBm and count 7.25 graticule lines down to the
highest emission level shown by the trace. Since each graticule line is
10 dB (indicated in the upper left-hand margin of the plot by 10 dB/ ),
the measured level is 72.5 dB (7.25 x 10) down from -45 dBm, or -117.5
dBm.

## RADIATED EMISSIONS MEASUREMENTS 

## 

##  In this set of measurements, spurious emissions generated by common consumer electronic and electrical devices are examined within the GPS L1, L2, and L5 frequency bands. The ARNS band was not examined primarily due to questions regarding the usefulness of this type of measurement in assessing those assumptions used to establish the UWB limits within this band. As discussed in Section 2 of this report, GPS does not operate, nor has plans to operate in this frequency band. Thus, the relevance of a comparison of spurious emissions generated from consumer devices to the theoretical GPS interference threshold is not immediately clear. Further, it seems questionable that the types of consumer devices considered in this effort will routinely operate within two meters of the aviation and military systems that utilize this frequency band (see Section 2 for a description of these systems). 

## 

## The radiated spurious emissions measurements were performed with the measurement system described previously. The measurement system was configured as it would be to determine compliance with the UWB emission limits. The device under test (DUT) was placed at a distance of two meters from the measurement antenna. This distance was selected to maintain consistency with the interaction distance assumed in the derivation of the UWB emission limit (see Section Three for details). At a distance of 

## 2-meters, the display line at --117.5 dBm directly relates to the EIRP limit of 

## -75.3 dBm/MHz defined within the rules. 

## 

##  Immediately preceding each measurement of the DUT-radiated spurious emissions, the measurement system was used to perform a check of the background or ambient RF environment in which the DUT was tested. This background measurement was performed using the same settings as used in the radiated emissions test. The resultant data was displayed using one of the three available traces of the spectrum analyzer. The DUT was then turned on and the radiated spurious emissions measurement was performed. The data from this measurement is displayed using another of the available analyzer traces. A single spectrum analyzer plot showing both traces was generated for each measurement band. The lower (yellow) trace represents the ambient (background) emission levels and the upper (blue) trace represents the sum of the ambient emissions and the spurious emissions originating from the DUT. 

## 

##  An important consideration in the interpretation of this data is the fact that the radiated spurious power captured by the measurement system is actually the sum of the ambient emissions already present and those spurious emissions introduced when the DUT is turned on. Since the emissions under consideration in this study are often very close to the ambient noise floor, the contribution of the noise floor to this sum can be significant. Within this study, if the difference between the measured ambient level and the corresponding radiated-plus-ambient level is 3 dB, then the DUT emission amplitude level is interpreted as being equivalent to the ambient level. Accordingly, if the difference between the DUT radiated-plus-ambient emission level and the corresponding ambient emission level is less than 3 dB, then the DUT emission level is interpreted as being less than the ambient level. Emissions that are more than 3 dB above the corresponding ambient level are attributed to spurious emissions from the DUT.

## Consumer Device Sample Set

Table 3-2 lists the consumer electronic/electrical devices measured as a
part of this effort.

**Table 3-2. Consumer Electronic/Electrical Devices Tested.**

  ------------------------ ----------------------------------------------
  **DEVICE**               **DESCRIPTION**

  Desktop Computer 1       Pentium IV

  Desktop Computer 2       Pentium II

  Desktop Computer 3       Pentium III w/ WLAN hub

  Laptop Computer 1        Pentium III

  Laptop Computer 2        Pentium I

  Laptop Computer 3        Pentium II

  Laptop Computer 4        Pentium II

  Personal Digital         
  Assistant                

  Pendant Transmitter      Automotive Remote Keyless Entry Device

  Electric Drill #1        Variable speed AC motor

  Electric Drill #2        Variable speed DC motor (cordless)

  Electric Hairdryer #1    Single speed AC motor

  Electric Hairdryer #2    Two speed AC motor

  Electric Vacuum Cleaner  Single speed AC motor
  ------------------------ ----------------------------------------------

###### Consumer Device Radiated Emissions Measurement Data

## 

## Appendix E presents the spectrum analyzer plots depicting the data collected from the measurement of radiated spurious emissions generated by those electronic/electrical devices contained in the sample set identified above for each of the GPS frequency bands. A sample plot from these measurements is presented below and used to facilitate the following explanation of how to read and interpret the represented data.

## The instructions provided earlier in this section for reading the ambient emission measurement analyzer plots are also applicable to reading the data represented in these plots. The following discussion highlights subtle differences between these plots and those depicting the ambient emissions measurements.

## ![](media/image3.wmf){width="6.0in" height="4.0in"} 

## In each of the spectrum analyzer plots presented in Appendix E, two measurement traces are shown. The lower (yellow) trace represents the background (ambient) emissions in the frequency band under examination with the DUT turned off. The upper (blue) trace represents the sum of the emissions radiated from the DUT and the existing background (ambient) emissions. A constant display line (green) is also shown in each plot. This is set to a level of -117.5 dBm to represent the received power equivalent to the UWB EIRP limit of -75.3 dBm/MHz at a distance of two meters. Some of the plots presented in Appendix E use other than 10 dB per vertical division (graticule line). This was done to facilitate better resolution of the signals under examination. These plots are read the same way as described previously except that each vertical line may represent a deviation of 3 or 5 dB from the reference level. The dB-per-division scale, applicable to each plot, is shown in the upper left-hand margin. 

**SECTION SIX**

**RESULTS**

**AMBIENT EMISSIONS MEASUREMENTS**

Tables 6-1 and 6-2 summarize specific data points from the spectrum
analyzer traces presented in Appendices C (outdoor ambient emissions
data) and D (indoor ambient emissions data). While it is difficult to
characterize all of the information provided in these plots within a
single table, an attempt has been made to present the most pertinent
data points from each plot such as the maximum emission amplitudes
observed in each frequency band, the associate frequency and general
signal structure, and the measured amplitude at the GPS center
frequency. However, the data in these tables does not convey information
such as the number of emissions observed in the band or the intermediate
amplitude levels (e.g., those emission levels less than the maximum
observed amplitude). This information must be obtained from the
individual spectral plots presented in the appendices.

The following explanation of each of the columns in these tables is
offered. The first column defines the frequency band that the subsequent
data pertains to. Column two shows the maximum emission amplitude (power
level) observed in the band. The values in column three compares the
maximum observed emission amplitude to the GPS interference threshold
assumed in the derivation of the UWB emission limit. Column four
provides the frequency associated with the maximum amplitude emission
observed. The fifth column describes the general emission characteristic
in terms of narrow band or broadband emissions. The final column shows
the measured emission amplitude at the center frequency of each of the
GPS bands. There are no entries provided in this column for the data
collected in the lower ARNS band, since GPS neither currently operates
nor has a future plan to operate in this band.

**RADIATED EMISSIONS MEASUREMENTS**

Table 6-3 summarizes the specific data points from the spectrum analyzer
traces from the measurements of radiated spurious emissions produced by
common electronic devices into the GPS frequency bands. The complete
data plots are presented in Appendix E. In this table, the column
descriptions presented above apply.

TABLE 6-1. Summary of Outdoor Ambient Emissions Measurement Data.

+---------+--------+---------+--------+--------------+--------------+
| **MEAS  | **M    | **E     | **EMIS | **EMISSION** | **MEASURED   |
| UREMENT | AXIMUM | MISSION | SION** |              | AMPLITUDE at |
| BAND**  | EM     | AM      |        | **CHAR       | GPS CENTER   |
|         | ISSION | PLITUDE | *      | ACTERISITC** | FREQUENCY**  |
| **      | AMPLI  | R       | *FREQU |              |              |
| (MHz)** | TUDE** | ELATIVE | ENCY** |              | **(dBm)**    |
|         |        | TO      |        |              |              |
|         | **(    | THRE    | **(    |              |              |
|         | dBm)** | SHOLD** | MHz)** |              |              |
|         |        |         |        |              |              |
|         |        | *       |        |              |              |
|         |        | *(dB)** |        |              |              |
+=========+========+=========+========+==============+==============+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Baltim  |        |         |        |              |              |
| ore-Was |        |         |        |              |              |
| hington |        |         |        |              |              |
| Intern  |        |         |        |              |              |
| ational |        |         |        |              |              |
| Ai      |        |         |        |              |              |
| rport** |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -117.5 | 0       | 1564   | Narrow Band  | -122.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -120.0 | -2.5    | 121    | Broad Band   | -122.0       |
|         |        |         | 5-1240 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -62.0  | 55.5    | 1185   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -112.0 | 5.5     | 984    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -83.0  | 34.5    | 1030   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -94.0  | 23.5    | 1090   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -87.0  | 30.5    | 1122   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Ronald  |        |         |        |              |              |
| Reagan  |        |         |        |              |              |
| N       |        |         |        |              |              |
| ational |        |         |        |              |              |
| Ai      |        |         |        |              |              |
| rport** |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -122.0 | -4.5    | 156    | Broad Band   | -122.0       |
|         |        |         | 3-1588 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -120.0 | -2.5    | 121    | Broad Band   | -122.0       |
|         |        |         | 5-1240 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -118.0 | -0.5    | 1165   | Narrow Band  | -122.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -82.0  | 35.5    | 1008   | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -95.0  | 22.5    | 1030   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -76.0  | 41.5    | 1072   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -90.0  | 27.5    | 1149   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Dulles  |        |         |        |              |              |
| Intern  |        |         |        |              |              |
| ational |        |         |        |              |              |
| Ai      |        |         |        |              |              |
| rport** |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -122.0 | -4.5    | 156    | Broad Band   | -122.0       |
|         |        |         | 3-1588 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -121.0 | -3.5    | 121    | Broad Band   | -122.0       |
|         |        |         | 5-1240 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -87.0  | 30.5    | 1169   | Narrow Band  | -122.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -119.0 | -1.5    | 96     | Broad Band   | N/A          |
| 60-1010 |        |         | 0-1010 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -80.0  | 37.5    | 1028   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -79.0  | 38.5    | 1106   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -94.0  | 23.5    | 1122 & | Narrow Band  | N/A          |
| 10-1160 |        |         | 1114   |              |              |
+---------+--------+---------+--------+--------------+--------------+

**TABLE 6-1 (continued). Summary of Outdoor Ambient Emissions
Measurement Data.**

+---------+--------+---------+--------+--------------+--------------+
| **MEAS  | **M    | **E     | **EMIS | **EMISSION** | **MEASURED   |
| UREMENT | AXIMUM | MISSION | SION** |              | AMPLITUDE at |
| BAND**  | EM     | AM      |        | **CHAR       | GPS CENTER   |
|         | ISSION | PLITUDE | *      | ACTERISITC** | FREQUENCY**  |
| **      | AMPLI  | R       | *FREQU |              |              |
| (MHz)** | TUDE** | ELATIVE | ENCY** |              | **(dBm)**    |
|         |        | TO      |        |              |              |
|         | **(    | THRE    | **(    |              |              |
|         | dBm)** | SHOLD** | MHz)** |              |              |
|         |        |         |        |              |              |
|         |        | *       |        |              |              |
|         |        | *(dB)** |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Port of |        |         |        |              |              |
| Balt    |        |         |        |              |              |
| imore** |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -118.0 | -0.5    | 156    | Broad Band   | -117.5       |
|         |        |         | 3-1588 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -117.0 | 0.5     | 121    | Broad Band   | -117.0       |
|         |        |         | 5-1240 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -85.0  | 32.5    | 1185   | Narrow Band  | -117.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -115.0 | 2.5     | 96     | Broad Band   | N/A          |
| 60-1010 |        |         | 0-1010 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -80.0  | 37.5    | 1030   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -82.0  | 35.5    | 1090 & | Narrow Band  | N/A          |
| 60-1110 |        |         | 1102   |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -95.0  | 22.5    | 1125   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| U.S.    |        |         |        |              |              |
| Coast   |        |         |        |              |              |
| Guard   |        |         |        |              |              |
| Yard**  |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -117.0 | 0.5     | 156    | Broad Band   | -117.0       |
|         |        |         | 3-1588 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -117.0 | 0.5     | 121    | Broad Band   | -117.0       |
|         |        |         | 5-1240 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -96.0  | 11.5    | 1185   | Narrow Band  | -117.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -111.0 | 6.5     | 975    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -85.0  | 32.5    | 1030   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -84.0  | 33.5    | 1071   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -83.0  | 34.5    | 1134   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| AMTRAK  |        |         |        |              |              |
| Main    |        |         |        |              |              |
| tenance |        |         |        |              |              |
| Fac     |        |         |        |              |              |
| ility** |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -117.0 | 0.5     | 1570   | Narrow Band  | -121.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -116.0 | 1.5     | 1234   | Narrow Band  | -120.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -113.0 | 4.5     | 1181   | Narrow Band  | -119.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -95.0  | 12.5    | 960    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -109.0 | 8.5     | 1030   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -95.0  | 12.5    | 1090   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -91.0  | 16.5    | 1116   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Urban   |        |         |        |              |              |
| (Indu   |        |         |        |              |              |
| strial) |        |         |        |              |              |
| Area**  |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -118.0 | -0.5    | 1575   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -117.5 | 0.0     | 1226   | Narrow Band  | -117.5       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -100.0 | 17.5    | 1164   | Narrow Band  | -117.5       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -77.0  | 40.5    | 960    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -86.0  | 31.5    | 1041   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -90.0  | 27.5    | 1090   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -95.0  | 22.5    | 1122   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+

TABLE 6-2. Summary of Indoor Ambient Emissions Measurement Data.

+---------+--------+---------+--------+--------------+--------------+
| **MEAS  | **M    | **E     | **EMIS | **EMISSION** | **MEASURED   |
| UREMENT | AXIMUM | MISSION | SION** |              | AMPLITUDE at |
| BAND**  | EM     | AM      |        | **CHAR       | GPS CENTER   |
|         | ISSION | PLITUDE | *      | ACTERISITC** | FREQUENCY**  |
| **      | AMPLI  | R       | *FREQU |              |              |
| (MHz)** | TUDE** | ELATIVE | ENCY** |              | **(dBm)**    |
|         |        | TO      |        |              |              |
|         | **(    | THRE    | **(    |              |              |
|         | dBm)** | SHOLD** | MHz)** |              |              |
|         |        |         |        |              |              |
|         |        | *       |        |              |              |
|         |        | *(dB)** |        |              |              |
+=========+========+=========+========+==============+==============+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Office  |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #1**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -108.0 | 9.5     | 1573   | Narrow Band  | -113.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -104.0 | 13.5    | 1220   | Narrow Band  | -109.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -94.0  | 23.5    | 1181   | Narrow Band  | -106.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -91.0  | 26.5    | 998    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -99.0  | 18.5    | 1040   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -93.0  | 24.5    | 1062   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -95.0  | 22.5    | 1119   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Office  |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #2**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -99.0  | 18.5    | 1575   | Narrow Band  | -101.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -94.0  | 23.5    | 1222   | Narrow Band  | -108.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -93.0  | 24.5    | 1169   | Narrow Band  | -98.0        |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -84.0  | 33.5    | 1009   | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -85.0  | 32.5    | 1036   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -83.0  | 34.5    | 1063   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -92.0  | 25.5    | 1125   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Office  |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #3**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -109.0 | 8.5     | 1572   | Narrow Band  | -113.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -115.0 | 2.5     | 121    | Broad Band   | -115.0       |
|         |        |         | 5-1240 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -114.0 | 3.5     | 1175   | Narrow Band  | -116.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -105.0 | 12.5    | 989    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -110.0 | 7.5     | 1020 & | Narrow Band  | N/A          |
| 10-1060 |        |         | 1050   |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -106.0 | 11.5    | 1090   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -110.0 | 7.5     | 1125   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Office  |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #4**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -97.0  | 20.5    | 1566   | Narrow Band  | -110.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -91.0  | 26.5    | 1233   | Narrow Band  | -108.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -81.0  | 36.5    | 1166   | Narrow Band  | -107.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -84.0  | 33.5    | 966    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -84.0  | 33.5    | 1033   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -84.0  | 33.5    | 1100   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -90.0  | 27.5    | 1133   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+

TABLE 6-2 (continued). Summary of Indoor Ambient Emissions Measurement
Data.

+---------+--------+---------+--------+--------------+--------------+
| **MEAS  | **M    | **E     | **EMIS | **EMISSION** | **MEASURED   |
| UREMENT | AXIMUM | MISSION | SION** |              | AMPLITUDE ON |
| BAND**  | EM     | AM      |        | **CHAR       | GPS CENTER   |
|         | ISSION | PLITUDE | *      | ACTERISITC** | FREQUENCY**  |
| **      | AMPLI  | R       | *FREQU |              |              |
| (MHz)** | TUDE** | ELATIVE | ENCY** |              | **(dBm)**    |
|         |        | TO      |        |              |              |
|         | **(    | THRE    | **(    |              |              |
|         | dBm)** | SHOLD** | MHz)** |              |              |
|         |        |         |        |              |              |
|         |        | *       |        |              |              |
|         |        | *(dB)** |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Office  |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #5**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -107.0 | 10.5    | 1571   | Narrow Band  | -115.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -106.0 | 11.5    | 1236   | Narrow Band  | -114.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -102.0 | 15.5    | 1164   | Narrow Band  | -114.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -102.0 | 15.5    | 1002   | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -102.0 | 15.5    | 1040   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -101.0 | 16.5    | 1104   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -103.0 | 14.5    | 1136   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Factory |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #1**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -105.0 | 12.5    | 1568   | Narrow Band  | -114.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -106.0 | 11.5    | 1225   | Narrow Band  | -109.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -100.0 | 17.5    | 99     | Narrow Band  | N/A          |
| 60-1010 |        |         | 5-1000 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -101.0 | 16.5    | 1038   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -94.0  | 23.5    | 1088   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -105.0 | 12.5    | 1117   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Factory |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #2**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -120.0 | -2.5    | 156    | Broad Band   | -120.0       |
|         |        |         | 3-1588 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -115.0 | 2.5     | 1229   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -117.5 | 0.0     | 116    | Broad Band   | -118.0       |
|         |        |         | 4-1189 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -114.0 | 3.5     | 998    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -114.0 | 3.5     | 1049   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -113.0 | 4.5     | 1088   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -104.0 | 13.5    | 1147   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| **Meas  |        |         |        |              |              |
| urement |        |         |        |              |              |
| Lo      |        |         |        |              |              |
| cation: |        |         |        |              |              |
| Factory |        |         |        |              |              |
| L       |        |         |        |              |              |
| ocation |        |         |        |              |              |
| #3**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -94.0  | 23.5    | 1574   | Narrow Band  | -105.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -80.0  | 37.5    | 1227   | Narrow Band  | -104.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -97.0  | 20.5    | 1170   | Narrow Band  | -106.0       |
+---------+--------+---------+--------+--------------+--------------+
| 9       | -91.0  | 26.5    | 984    | Narrow Band  | N/A          |
| 60-1010 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -95.0  | 22.5    | 1023   | Narrow Band  | N/A          |
| 10-1060 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 10      | -93.0  | 24.5    | 1091   | Narrow Band  | N/A          |
| 60-1110 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| 11      | -90.0  | 27.5    | 1134   | Narrow Band  | N/A          |
| 10-1160 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+

TABLE 6-3. Summary of Radiated Spurious Emissions Measurement Data.

+---------+--------+---------+--------+--------------+--------------+
| **MEAS  | **M    | **E     | **EMIS | **EMISSION** | **MEASURED   |
| UREMENT | AXIMUM | MISSION | SION** |              | AMPLITUDE ON |
| BAND**  | EM     | AM      |        | **CHAR       | GPS CENTER   |
|         | ISSION | PLITUDE | *      | ACTERISITC** | FREQUENCY**  |
| **      | AMPLI  | R       | *FREQU |              |              |
| (MHz)** | TUDE** | ELATIVE | ENCY** |              | **(dBm)**    |
|         |        | TO      |        |              |              |
|         | **(    | THRE    | **(    |              |              |
|         | dBm)** | SHOLD** | MHz)** |              |              |
|         |        |         |        |              |              |
|         |        | *       |        |              |              |
|         |        | *(dB)** |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| # DU    |        |         |        |              |              |
| T: Desk |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 1 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -103.0 | 14.5    | 1584   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -115.0 | 2.5     | 1224   | Narrow Band  | -116.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -110.0 | 7.5     | 1165   | Narrow Band  | -116.0       |
+---------+--------+---------+--------+--------------+--------------+
| ## DU   |        |         |        |              |              |
| T: Desk |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 2 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -119.0 | -1.5    | 1573   | Narrow Band  | -120.0       |
|         |        |         |        | (Ambient)    |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -116.0 | 1.5     | 1222   | Narrow Band  | -119.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -114.0 | 3.5     | 1167   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| # DU    |        |         |        |              |              |
| T: Desk |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 3 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -113.0 | 4.5     | 1563   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -109.0 | 8.5     | 1216   | Narrow Band  | -114.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -111.0 | 6.5     | 1166   | Narrow Band  | -115.0       |
+---------+--------+---------+--------+--------------+--------------+
| ## D    |        |         |        |              |              |
| UT: Lap |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 1 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -113.0 | 4.5     | 1563   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -111.0 | 6.5     | 1227   | Narrow Band  | -116.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -114.0 | 3.5     | 1164   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| ## D    |        |         |        |              |              |
| UT: Lap |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 2 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -112.0 | 5.5     | 1564   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -103.0 | 14.5    | 1238   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -109.0 | 8.5     | 1173   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+
| ## D    |        |         |        |              |              |
| UT: Lap |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 3 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -116.0 | 1.5     | 1584   | Narrow Band  | -117.5       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -109.0 | 8.5     | 1235   | Narrow Band  | -116.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -104.0 | 13.5    | 1170   | Narrow Band  | -115.0       |
+---------+--------+---------+--------+--------------+--------------+
| ## D    |        |         |        |              |              |
| UT: Lap |        |         |        |              |              |
| top Com |        |         |        |              |              |
| puter 4 |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -114.0 | 3.5     | 1563   | Narrow Band  | -119.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -112.0 | 5.5     | 1238   | Narrow Band  | -119.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -106.0 | 11.5    | 1173   | Narrow Band  | -118.0       |
+---------+--------+---------+--------+--------------+--------------+

TABLE 6-3 (continued). Summary of Radiated Spurious Emissions
Measurement Data.

+---------+--------+---------+--------+--------------+--------------+
| **MEAS  | **M    | **E     | **EMIS | **EMISSION** | **MEASURED   |
| UREMENT | AXIMUM | MISSION | SION** |              | AMPLITUDE ON |
| BAND**  | EM     | AM      |        | **CHAR       | GPS CENTER   |
|         | ISSION | PLITUDE | *      | ACTERISITC** | FREQUENCY**  |
| **      | AMPLI  | R       | *FREQU |              |              |
| (MHz)** | TUDE** | ELATIVE | ENCY** |              | **(dBm)**    |
|         |        | TO      |        |              |              |
|         | **(    | THRE    | **(    |              |              |
|         | dBm)** | SHOLD** | MHz)** |              |              |
|         |        |         |        |              |              |
|         |        | *       |        |              |              |
|         |        | *(dB)** |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| ## D    |        |         |        |              |              |
| UT: PDA |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -118.0 | -0.5    | 156    | Broad Band   | -118.0       |
|         |        |         | 3-1588 |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -109.0 | 8.5     | 1216   | Narrow Band  | -114.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -111.0 | 6.5     | 1166   | Narrow Band  | -115.0       |
+---------+--------+---------+--------+--------------+--------------+
| ## DUT  |        |         |        |              |              |
| : Penda |        |         |        |              |              |
| nt Tran |        |         |        |              |              |
| smitter |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -90.0  | 27.5    | 1575   | Narrow Band  | -95.0        |
+---------+--------+---------+--------+--------------+--------------+
| **DUT:  |        |         |        |              |              |
| E       |        |         |        |              |              |
| lectric |        |         |        |              |              |
| Drill   |        |         |        |              |              |
| #1**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -100.0 | 17.5    | 1574   | Imp          | -110.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -87.0  | 30.5    | 1239   | Imp          | -105.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -84.0  | 34.5    | 1188   | Imp          | -90.0        |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| **DUT:  |        |         |        |              |              |
| E       |        |         |        |              |              |
| lectric |        |         |        |              |              |
| Drill   |        |         |        |              |              |
| #2**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  |        |         |        | Impulsive    |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -110.0 | 7.5     | 1233   | Impulsive    | -117.5       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -113.0 | 4.5     | 1167   | Impulsive    | -117.5       |
+---------+--------+---------+--------+--------------+--------------+
| **DUT:  |        |         |        |              |              |
| E       |        |         |        |              |              |
| lectric |        |         |        |              |              |
| Hair    |        |         |        |              |              |
| Dryer   |        |         |        |              |              |
| #1**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -100.0 | 17.5    | 1589   | Imp          | -111.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -99.0  | 18.5    | 1217   | Imp          | -116.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -95.0  | 22.5    | 1182   | Imp          | -111.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| **DUT:  |        |         |        |              |              |
| E       |        |         |        |              |              |
| lectric |        |         |        |              |              |
| Hair    |        |         |        |              |              |
| Dryer   |        |         |        |              |              |
| #2**    |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -106.0 | 11.5    | 1577   | Impulsive    | -119.0       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -110.0 | 7.5     | 1235   | Impulsive    | -117.5       |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -111.0 | 6.5     | 1165   | Impulsive    | -117.0       |
+---------+--------+---------+--------+--------------+--------------+
| **DUT:  |        |         |        |              |              |
| E       |        |         |        |              |              |
| lectric |        |         |        |              |              |
| Vacuum  |        |         |        |              |              |
| Cl      |        |         |        |              |              |
| eaner** |        |         |        |              |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L1  | -103.0 | 14.5    | 1578   | Imp          | -106.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L2  | -102.0 | 15.5    | 1238   | Imp          | -103.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+
| GPS L5  | -100.0 | 17.5    | 1169   | Imp          | -102.0       |
|         |        |         |        | ulsive-Broad |              |
|         |        |         |        | Band         |              |
+---------+--------+---------+--------+--------------+--------------+

**SECTION SEVEN**

#### OBSERVATIONS, CONCLUSIONS

#### AND RECOMMENDATIONS

**OBSERVATIONS**

**Ambient Emissions Measurements - Outdoor Sites**

The ambient emissions measurements performed in the GPS L1 and L2
frequency bands reveal these two bands to be relatively quiet with
respect to existing RF activity. At most of the outdoor locations, no
emissions exceeding the sensitivity of the measurement system were
detected. At those few locations where emissions were observed, the
associated power levels were determined to be very low, and in all
cases, less than the interference threshold assumed for GPS receivers in
the derivation of the UWB limits applicable in these frequency bands.

Ambient emissions measurements performed in the GPS L5 frequency band
disclose a greater level of RF activity than in the GPS L1 and L2
frequency bands. Existing ambient emissions were observed in this band
at many of the measurement locations; however, they appear to be
associated with frequency assignments to what are assumed to be
authorized systems operating in the band. In all locations, the
emissions detected in this band were removed in frequency from the GPS
L5 center frequency. The waveforms associated with these emissions were
observed to decrease to amplitude levels less than the assumed GPS
interference threshold within the likely pass band of a GPS L5 receiver.

The ambient emissions measurements performed in the lower ARNS band
(960-1160 MHz) show a high level of RF activity within this region of
the spectrum. At all measurement sites significant emissions were
observed in the band with associated power levels well in excess of the
assumed interference threshold. Existing ambient emissions were observed
in the band, at levels up to 35 dB (more than 3000 times) greater than
the interference threshold assumed in deriving the UWB emission limits
applicable to the band. For some of these observed emissions the
source(s) were readily identifiable (e.g., the Air Traffic Control Radio
Beacon System interrogator and reply); however, for many others the
source was not readily known.

**Ambient Emissions Measurements - Indoor Sites**

When the measurement system was moved indoors to detect the presence and
amplitude of existing ambient emissions at those locations consistent
with the operational scenario assumed in the derivation of the UWB
emission limits (e.g., inside office buildings, factories, etc), a
different trend emerged. In the outdoor measurements, no distinct
emissions were observed in either the GPS L1 or L2 frequency bands.
However, at many of the indoor measurement locations, narrow-band
emissions were observed at amplitudes exceeding the assumed GPS
interference threshold by as much as 37.5 dB (i.e., by more than 5600
times). It was beyond the scope of this effort to identify the source of
these emissions; however, it was presumed that they emanate from
existing electronic devices (e.g., computers and peripherals, copiers,
etc) and other man-made noise generated by a variety of other office
equipment including electric motors. The magnitude of these emissions
was observed to be related to the density and distribution of the
electronic systems present within the immediate measurement environment.

It is recognized that a comparison, in terms of interference potential,
between a narrow-band ambient emission and a UWB emission is specious
unless the narrow band signal is coincident with the pass band of a GPS
receiver. However, at several of the indoor measurement sites the
maximum-amplitude narrow-band emission was indeed detected at
frequencies coincident with the pass band of a GPS receiver (e.g.,
Office Location #2, and Factory Location #3). In other cases, although
the maximum-amplitude emission did not fall within the pass band, one of
the intermediate-amplitude emissions did.

Finally, a comparison between the values presented in the last columns
of Tables 6-1 and 6-2 reveal that the measurement system experienced
some level of desensitization at all but one of the indoor measurement
sites. For the outdoor measurement locations, the minimum detectable
ambient signal was typically limited only by the sensitivity of the
measurement system. However, for all but one of the indoor measurement
locations the minimum detectable signal was limited not by the
measurement system sensitivity, but by the existing ambient noise
environment. This measurement system desensitization ranged between 2
and 24 dB, depending on the measurement band and location. Since the
measurement system was configured to simulate the RF front-end of a GPS
receiver, it is reasonable to expect that a GPS receiver would likely
experience a similar desensitization.

Similar results were observed in both the GPS L5 and the lower ARNS
band. At least some of the ambient emissions detected in the ARNS band
were attributed to known systems (e.g., ATCRBS) but at reduced
amplitudes (relative to the outdoor measurement data) as a result of
signal attenuation through the building walls.

### Radiated Emissions Measurements

Narrow-band spurious emissions, radiating from those consumer-grade
electronic devices tested as a part of this effort, were observed in
each of the GPS frequency bands. The power density levels associated
with these emissions were typically low relative to the applicable
emissions limit (e.g., Part 15.109[^22]), but were nonetheless in excess
of the UWB emission limits by as much as 27.5 dB (more than 500 times
greater). Stated another way, each of the devices measured complies with
the applicable emission limits in the frequency bands under examination;
however, if they were subjected to the emission limits for UWB, most of
the devices examined would fail a compliance test.

All of the radiated spurious emissions observed from the consumer-grade
electronic devices were narrow band in structure. As stated previously,
a comparison, in terms of interference potential, between a narrow-band
ambient emission and a UWB emission is specious unless the narrow band
signal is coincident with the pass band of a GPS receiver. Such was the
case for two of the devices examined (Laptop Computer #2 and the Pendant
Transmitter). Based on these observations, it is reasonable to suspect
that other unlicensed electronic devices exist, although not examined
within this effort, whose circuitry also generates spurious emissions
into these bands, and perhaps also within the GPS receiver pass band.

Emissions were also observed from the consumer-grade electrical devices
in all of the measurement bands at various amplitude levels, most of
which exceeded the GPS receiver interference threshold assumed in the
derivation of the UWB limit. The emissions observed from these
measurements are all attributed to electromagnetic energy resulting from
the armature-stator interaction common to all electric motors. These
types of emission sources are deemed incidental radiators since their
function does not require the generation of radio frequency signals. The
power density associated with these types of emissions attenuates
rapidly with separation distance, and thus they are not usually
considered in interference analyses to electronic systems. Because of
the low potential for interference from these types of devices to
electronic-communication systems, the FCC does not regulate them. The
following statement from the Code of Federal Regulations is the only
applicable regulation with regard to these devices: "Manufacturers of
these devices shall employ good engineering practices to minimize the
risk of harmful interference."[^23] However, under extremely
conservative assumptions, such as the two-meter interaction distance
assumed in deriving the UWB emission limits, these types of devices can
also be considered as potential interferers.

The data collected from this part of the effort shows that when measured
at a distance of two meters, the radiated emission amplitudes from the
consumer-grade electrical devices were as much as 34.5 dB (more than
2800 times) greater than the assumed interference threshold within the
GPS registered frequency bands. The data further shows that these
emission amplitudes were as much as 27.5 dB (more than 560 times)
greater than the theoretical GPS interference threshold within the pass
band of a GPS receiver.

## 

## CONCLUSIONS

The following statement was included in the NTIA letter and was
incorporated into the UWB R&O. "..., the minimum level of the GPS signal
that can be used for an E-911 position determination will be determined
by the receiver system noise density.*"*[^24] The ambient measurement
results show that the GPS L1 and L2 frequency bands are quiet with
respect to existing ambient emissions at those outdoor locations where
tests were conducted. However, the data also reveals that in at least
some locations, particularly indoor locations similar to those assumed
in the derivation of the UWB emission limits, the ambient noise
environment, rather than the GPS receiver thermal noise density, may
actually be the limitation to the reception of the low-amplitude GPS
signals.

The radiated emissions measurement results show that although many of
the devices tested radiate emissions into the GPS frequency bands, the
associated amplitudes were at much lower levels than permitted by the
applicable limits. However, it was also determined that the amplitudes
(power density) associated with these emissions were frequently in
excess of the limits established for UWB emissions.

As part of this measurement effort, the ambient noise environment in the
lower ARNS (960-1160 MHZ) frequency band was also examined. This band is
not used to support GPS operations nor is it identified for use in the
GPS modernization plan. Rather this frequency band is used to support
terrestrial-based navigational aids such as the Distance Measuring
Equipment (DME) and the Air Traffic Control Radio Beacon (ATCRBS). NTIA
stated that \"the operational limits required for the protection of the
GPS will also be adequate to protect DME operations.\" The measurement
results show that the ambient emissions in this band are generally above
the adopted UWB emission limits. Thus it appears that the limiting
factor in this band will also be the ambient noise environment rather
than the limit based on the GPS receiver thermal noise density. In
addition, Table 6 in the NTIA letter shows that a maximum EIRP of -64
dBm/MHz is required to protect the DME system under the most
conservative assumptions, which is well above both the adopted UWB limit
and the ambient noise environment for this band.\"

APPENDIX A

MEASURMENT SYSTEM CALIBRATION DATA

In this appendix, the spectrum analyzer plots produced from the
calibration of the RF front-end (between the antenna input and the
spectrum analyzer input) of the two measurement systems used to collect
the data in this effort are presented. This calibration was performed by
inserting a known-amplitude continuous wave (CW) signal into the antenna
input of the measurement system. The signal was swept across each of the
frequency bands under examination in this measurement effort. The
spectrum analyzer was used to record the resultant power as a function
of frequency. A calibrated signal generator was used to provide the CW
signal. The input amplitude was set at --80 dBm for the calibration of
System A and at -- 65 dBm for the calibration of System B. The resultant
spectrum analyzer trace depicts the signal gain (or loss) in the RF
chain over the frequency range under examination and is reported in
Tables A-1 and A-2 as the measurement system external gain. This
external gain is the sum of the gain provided by the cascaded low noise
amplifiers less the attenuation in the coaxial cables, connectors,
isolation pad, and the insertion loss of the band pass filter.

Table A-1 summarizes the data obtained from the calibration curves for
Measurement System A, given in figures A-1 through A-7. Table A-2
summarizes the data obtained from the calibration of Measurement System
B, with the complete data provided in Figures A-8 through A-14.

**TABLE A-1. Measurement System External Gain (System A).**

+---------------------------------+------------------------------------+
| **CENTER**                      | #                                  |
|                                 |  MEASUREMENT SYSTEM EXTERNAL GAIN  |
| **FREQUENCY**                   |                                    |
|                                 | **(dB)**                           |
| **(MHz)**                       |                                    |
+---------------------------------+------------------------------------+
| 1575.4                          | 64.8                               |
+---------------------------------+------------------------------------+
| 1227.6                          | 66.7                               |
+---------------------------------+------------------------------------+
| 1176.0                          | 66.4                               |
+---------------------------------+------------------------------------+
| 985.0                           | 68.0                               |
+---------------------------------+------------------------------------+
| 1035.0                          | 67.7                               |
+---------------------------------+------------------------------------+
| 1085.0                          | 67.3                               |
+---------------------------------+------------------------------------+
| 1135.0                          | 67.0                               |
+---------------------------------+------------------------------------+

**TABLE 4-3. Measurement System External Gain (System B).**

+---------------------------------+------------------------------------+
| **CENTER**                      | #                                  |
|                                 |  MEASUREMENT SYSTEM EXTERNAL GAIN  |
| **FREQUENCY**                   |                                    |
|                                 | **(dB)**                           |
| **(MHz)**                       |                                    |
+---------------------------------+------------------------------------+
| 1575.4                          | 63.5                               |
+---------------------------------+------------------------------------+
| 1227.6                          | 64.7                               |
+---------------------------------+------------------------------------+
| 1176.0                          | 64.9                               |
+---------------------------------+------------------------------------+
| 985.0                           | 67.4                               |
+---------------------------------+------------------------------------+
| 1035.0                          | 66.7                               |
+---------------------------------+------------------------------------+
| 1085.0                          | 66.6                               |
+---------------------------------+------------------------------------+
| 1135.0                          | 66.2                               |
+---------------------------------+------------------------------------+

![](media/image4.png){width="6.0in" height="4.0in"}

Figure A-1. Measurement System A Calibration Over GPS L1 Frequency Band.

![](media/image5.png){width="6.0in" height="4.0in"}

Figure A-2. Measurement System A Calibration Over GPS L2 Frequency Band.

![](media/image6.png){width="6.0in" height="4.0in"}

Figure A-3. Measurement System A Calibration Over GPS L5 Frequency Band.

![](media/image7.png){width="6.0in" height="4.0in"}

Figure A-4. Measurement System A Calibration Over 960-1010 MHz Frequency
Band.

![](media/image8.png){width="6.0in" height="4.0in"}

Figure A-5. Measurement System A Calibration Over 1010-1060 MHz
Frequency Band.

![](media/image9.png){width="6.0in" height="4.0in"}

Figure A-6. Measurement System A Calibration Over 1060-1110 MHz
Frequency Band.

![](media/image10.png){width="6.0in" height="4.0in"}

Figure A-7. Measurement System A Calibration Over 1110-1160 MHz
Frequency Band.

![](media/image11.png){width="6.0in" height="4.0in"}

Figure A-8. Measurement System B Calibration Over GPS L1 Frequency Band.

![](media/image12.png){width="6.0in" height="4.0in"}

Figure A-9. Measurement System B Calibration Over GPS L2 Frequency Band.

![](media/image13.png){width="6.0in" height="4.0in"}

Figure A-10. Measurement System B Calibration Over GPS L5 Frequency
Band.

![](media/image14.png){width="6.0in" height="4.0in"}

Figure A-11. Measurement System B Calibration Over 960-1010 MHz
Frequency Band.

![](media/image15.png){width="6.0in" height="4.0in"}

Figure A-12. Measurement System B Calibration Over 1010-1060 MHz
Frequency Band.

![](media/image16.png){width="6.0in" height="4.0in"}

Figure A-13. Measurement System B Calibration Over 1060-1110 MHz
Frequency Band.

![](media/image17.png){width="6.0in" height="4.0in"}

Figure A-14. Measurement System B Calibration Over 1110-1160 MHz
Frequency Band.

## APPENDIX B

**MEASUREMENT PROCEDURES**

## 

This appendix presents the procedures used for collection of the data
utilized in this report.

## AMBIENT EMISSIONS MEASUREMENT PROCEDURES

The following procedures were applied in performing the measurements at
each ambient emissions measurement location:

1.  Set-up the measurement system as shown in Figure 2-1.

2.  Set measurement antenna to a nominal height of four feet above
    ground level (roughly equivalent to typical height of a hand-held
    GPS receiver or E-911 enabled cell phone)

3.  Orient the measurement antenna in vertical polarization and rotate
    through 360° observing peak signals and probable direction.

4.  Repeat with antenna oriented in horizontal polarization.

5.  Review the collected data to determine antenna polarization and the
    bearing that maximizes the received emission levels.

6.  Using the data obtained from the previous steps, set up the spectrum
    analyzer display (e.g., reference level, amplitude scale,
    attenuation levels, etc.) to accommodate all subsequent
    measurements. Set the analyzer display line to --117.5 dBm.

7.  Sequentially measure over each of the frequency bands under
    consideration (i.e., GPS L1, L2, and L5, and ARNS band segment)
    collecting peak emission traces and RMS average emission traces, by
    utilizing two of the three available analyzer traces.

8.  When relatively high emission levels are observed, perform a system
    saturation test by inputting an additional 10-dB attenuator at the
    spectrum analyzer input and verifying that the received signal is
    attenuated by 10 dB.

9.  Store the composite analyzer displays and associated trace data onto
    computer disk.

10. Record the relevant measurement site information, i.e., GPS
    coordinates, street address, site description, date, time, and
    antenna bearing.

## RADIATED EMISSIONS MEASUREMENT PROCEDURES

The following procedures were implemented in the measurement of radiated
emissions from common consumer electronic and electrical devices into
the GPS frequency bands:

1.  Assemble measurement system as shown in Figure 2-1.

2.  Place the device under test (DUT) in the center of a non-conductive
    turntable and turn power on.

3.  Place the measurement antenna at a distance of two meters from the
    DUT.

4.  Use turntable to rotate the DUT through 360° with the measurement
    antenna oriented in vertical polarization.

5.  Re-orient the measurement antenna to horizontal polarization and
    again rotate the DUT through 360°.

6.  Review the data and observe the antenna polarization and the azimuth
    with respect to the DUT that produces the maximum emission levels.
    Use this polarization and DUT orientation for the remainder of the
    test.

7.  With DUT radiating, move the measurement antenna up and down
    (between approximately 1 and 3 meters) to determine the antenna
    height at which the emissions are maximized. Set the antenna to the
    height determined from this procedure.

8.  Using the data acquired in the previous steps, set up the spectrum
    analyzer display (e.g., reference level, amplitude scale,
    attenuation levels, etc.) to accommodate all subsequent
    measurements. Set the analyzer display line to --117.5 dBm.

9.  Turn the DUT off and use the spectrum analyzers' trace 1 feature to
    record the ambient RF background.

10. Turn the DUT on and tune the spectrum analyzer to one of the
    frequency bands under consideration. Use analyzer trace 2 to record
    the RMS average emission from the DUT and use trace 3 to record the
    Log average measured emissions.

11. Store the composite analyzer trace and associated trace data to
    computer disk.

12. Repeat steps 9-11 for each of the frequency bands under
    consideration.

    **APPENDIX C**

**OUTDOOR AMBIENT EMISSIONS MEASUREMENT DATA**

The data plots recorded from the measurement of existing ambient
emissions at outdoor sites such as airports, shipyards, train yards, and
urban/industrial locations are presented in this appendix. The following
paragraphs provide guidance on reading and interpreting these plots.

In each of the figures presented in this appendix, the upper (yellow)
trace depicts the ambient emissions measured in the subject frequency
band using a peak detector and the maximum hold function (i.e., no
averaging employed) over a fifteen-minute period. This trace was
generated mainly as a tool for orienting the measurement antenna and for
determining the maximum likely emission amplitudes to facilitate
decisions pertaining to the necessity of adding additional attenuation
in the measurement system so as to prevent overdriving of components.
This data was not used for any analytical purposes. The lower (blue)
trace represents the measured RMS average emission level over one
hundred one-millisecond analyzer sweeps across the measurement band.
This is the data used to compare to the assumed interference threshold
for enhanced GPS receivers. The constant display line (green) at -117.5
dBm is used as the basis for comparing the measured data to the
theoretical enhanced GPS interference threshold.

All external measurement system parameters (e.g., amplifier gains, cable
loss, and antenna gain) are accounted for in the spectrum analyzer
display and are provided on each plot under the tag Ext PG located at
the top of the display. At some measurement locations, it was necessary
to add additional attenuation in the measurement system due to the
presence of relatively high-amplitude signals. In those cases where
additional external attenuation was required, the Ext PG value was
adjusted accordingly. Thus, the levels shown on the amplitude axis of
the spectrum analyzer plots represent the actual RMS average power as
measured in a 1 MHz bandwidth at the measurement system antenna.

In each of these plots, the horizontal axis represents frequency and the
vertical axis represents amplitude. For measurements in the GPS
frequency bands, a span of 25 MHz was used to encompass the 24 MHz
registered frequency band. For a 25 MHz span, each vertical graticule
line represents a 2.5 MHz deviation in frequency (25 MHz/10 graticule
lines). For the measurements performed in the 960-1160 MHz (ARNS) band,
a span of 50 MHz was used, the maximum that could be achieved within the
pass band of the pre-select filter. In these plots, each vertical
graticule line represents a frequency deviation of 5 MHz (50 MHz/10
graticule lines).

On the amplitude axis, each horizontal graticule line represents a 10 dB
decrement from the reference level amplitude shown in the upper
left-hand corner of the plot.

![](media/image2.png){width="6.0in" height="4.0in"}

Figure C-15. Ambient Emissions in the GPS L1 Frequency Band at BWI
Airport.

![](media/image18.png){width="6.0in" height="4.0in"}

Figure C-16. Ambient Emissions in the GPS L2 Frequency Band at BWI
Airport.

![](media/image19.png){width="6.0in" height="4.0in"}

Figure C-17. Ambient Emissions in the GPS L5 Frequency Band at BWI
Airport.

![](media/image20.png){width="6.0in" height="4.0in"}

Figure C-18. Ambient Emissions in the 960-1010 MHz Frequency Band at BWI
Airport.

![](media/image21.png){width="6.0in" height="4.0in"}

Figure C-19. Ambient Emissions in the 1010-1060 MHz Frequency Band at
BWI Airport.

![](media/image22.png){width="6.0in" height="4.0in"}

Figure C-20. Ambient Emissions in the 1060-1110 MHz Frequency Band at
BWI Airport.

![](media/image23.png){width="6.0in" height="4.0in"}

Figure C-21. Ambient Emissions in the 1110-1160 MHz Frequency Band at
BWI Airport.

![](media/image24.png){width="6.0in" height="4.0in"}

Figure C-22. Ambient Emissions in the GPS L1 Frequency Band at Reagan
National Airport.

![](media/image25.png){width="6.0in" height="4.0in"}

Figure C-23. Ambient Emissions in the GPS L2 Frequency Band at Reagan
National Airport.

![](media/image26.png){width="6.0in" height="4.0in"}

Figure C-24. Ambient Emissions in the GPS L5 Frequency Band at Reagan
National Airport.

![](media/image27.png){width="6.0in" height="4.0in"}

Figure C-25. Ambient Emissions in the 960-1010 MHz Frequency Band at
Reagan National Airport.

![](media/image28.png){width="6.0in" height="4.0in"}

Figure C-26. Ambient Emissions in the 1010-1060 MHz Frequency Band at
National Airport.

![](media/image29.png){width="6.0in" height="4.0in"}

Figure C-27. Ambient Emissions in the 1060-1110 MHz Frequency Band at
National Airport.

![](media/image30.png){width="6.0in" height="4.0in"}

Figure C-28. Ambient Emissions in the 1110-1160 MHz Frequency Band at
National Airport.

![](media/image31.png){width="6.0in" height="4.0in"}

Figure C-29. Ambient Emissions in the GPS L1 Frequency Band at Dulles
International Airport.

![](media/image32.png){width="6.0in" height="4.0in"}

Figure C-30. Ambient Emissions in the GPS L2 Frequency Band at Dulles
International Airport.

![](media/image33.png){width="6.0in" height="4.0in"}

Figure C-31. Ambient Emissions in the GPS L5 Frequency Band at Dulles
International Airport.

![](media/image34.png){width="6.0in" height="4.0in"}

Figure C-32. Ambient Emissions in the 960-1010 MHz Frequency Band at
Dulles Airport.

![](media/image35.png){width="6.0in" height="4.0in"}

Figure C-33. Ambient Emissions in the 1010-1060 MHz Frequency Band at
Dulles Airport.

![](media/image36.png){width="6.0in" height="4.0in"}

Figure C-34. Ambient Emissions in the 1060-1110 MHz Frequency Band at
Dulles Airport.

![](media/image37.png){width="6.0in" height="4.0in"}

Figure C-35. Ambient Emissions in the 1110-1160 MHz Frequency Band at
Dulles Airport.

![](media/image38.png){width="6.0in" height="4.0in"}

Figure C-36. Ambient Emissions in the GPS L1 Frequency Band at the Port
of Baltimore.

![](media/image39.png){width="6.0in" height="4.0in"}

Figure C-37. Ambient Emissions in the GPS L2 Frequency Band at the Port
of Baltimore.

![](media/image40.png){width="6.0in" height="4.0in"}

Figure C-38. Ambient Emissions in the GPS L5 Frequency Band at the Port
of Baltimore.

![](media/image41.png){width="6.0in" height="4.0in"}

Figure C-39. Ambient Emissions in the 960-1010 MHz Frequency Band at the
Port of Baltimore.

![](media/image42.png){width="6.0in" height="4.0in"}

Figure C-40. Ambient Emissions in the 1010-1060 MHz Frequency Band at
the Port of Baltimore.

![](media/image43.png){width="6.0in" height="4.0in"}

Figure C-41. Ambient Emissions in the 1060-1110 MHz Frequency Band at
the Port of Baltimore.

![](media/image44.png){width="6.0in" height="4.0in"}

Figure C-42. Ambient Emissions in the 1110-1160 MHz Frequency Band at
the Port of Baltimore.

![](media/image45.png){width="6.0in" height="4.0in"}

Figure C-43. Ambient Emissions in the GPS L1 Frequency Band at the U.S.
Coast Guard Yard.

![](media/image46.png){width="6.0in" height="4.0in"}

Figure C-44. Ambient Emissions in the GPS L2 Frequency Band at the U.S.
Coast Guard Yard.

![](media/image47.png){width="6.0in" height="4.0in"}

Figure C-45. Ambient Emissions in the GPS L5 Frequency Band at the U.S.
Coast Guard Yard.

![](media/image48.png){width="6.0in" height="4.0in"}

Figure C-46. Ambient Emissions in the 960-1010 MHz Frequency Band at the
Coast Guard Yard.

![](media/image49.png){width="6.0in" height="4.0in"}

Figure C-47. Ambient Emissions in the 1010-1060 MHz Frequency Band at
the Coast Guard Yard.

![](media/image50.png){width="6.0in" height="4.0in"}

Figure C-48. Ambient Emissions in the 1060-1110 MHz Frequency Band at
the Coast Guard Yard.

![](media/image51.png){width="6.0in" height="4.0in"}

Figure C-49. Ambient Emissions in the 1110-1160 MHz Frequency Band at
the Coast Guard Yard.

![](media/image52.png){width="6.0in" height="4.0in"}

Figure C-50. Ambient Emissions in the GPS L1 Frequency Band at the
AMTRAK Train Yard.

![](media/image53.png){width="6.0in" height="4.0in"}

Figure C-51. Ambient Emissions in the GPS L2 Frequency Band at the
AMTRAK Train Yard.

![](media/image54.png){width="6.0in" height="4.0in"}

Figure C-52. Ambient Emissions in the GPS L5 Frequency Band at the
AMTRAK Train Yard.

![](media/image55.png){width="6.0in" height="4.0in"}

Figure C-53. Ambient Emissions in the 960-1010 MHz Frequency Band at the
Train Yard.

![](media/image56.png){width="6.0in" height="4.0in"}

Figure C-54. Ambient Emissions in the 1010-1060 MHz Frequency Band at
the Train Yard.

![](media/image57.png){width="6.0in" height="4.0in"}

Figure C-55. Ambient Emissions in the 1060-1110 MHz Frequency Band at
the Train Yard.

![](media/image58.png){width="6.0in" height="4.0in"}

Figure C-56. Ambient Emissions in the 1110-1160 MHz Frequency Band at
the Train Yard.

![](media/image59.png){width="6.0in" height="4.0in"}

Figure C-57. Ambient Emissions in the GPS L1 Frequency Band at
Urban/Industrial Site.

![](media/image60.png){width="6.0in" height="4.0in"}

Figure C-58. Ambient Emissions in the GPS L2 Frequency Band at
Urban/Industrial Site.

![](media/image61.png){width="6.0in" height="4.0in"}

Figure C-59. Ambient Emissions in the GPS L5 Frequency Band at
Urban/Industrial Site.

![](media/image62.png){width="6.0in" height="4.0in"}

Figure C-60. Ambient Emissions in the 960-1010 MHz Frequency Band at
Urban/Industrial Site.

![](media/image63.png){width="6.0in" height="4.0in"}

Figure C-61. Ambient Emissions in the 1010-1060 MHz Frequency Band at
Urban/Industrial Site.

![](media/image64.png){width="6.0in" height="4.0in"}

Figure C-62. Ambient Emissions in the 1060-1110 MHz Frequency Band at
Urban/Industrial Site.

![](media/image65.png){width="6.0in" height="4.0in"}

Figure C-63. Ambient Emissions in the 1110-1160 MHz Frequency Band at
Urban/Industrial Site.

APPENDIX D

INDOOR AMBIENT EMISSIONS MEASUREMENT DATA

The data plots recorded from the measurement of existing ambient
emissions at indoor sites such as office buildings and factory
facilities are presented in this appendix. The following paragraphs
provide guidance on reading and interpreting these plots.

In each of the figures presented in this appendix, the upper (yellow)
trace depicts the ambient emissions measured in the subject frequency
band using a peak detector and the maximum hold function (i.e., no
averaging employed) over a fifteen-minute period. This trace was
generated mainly as a tool for orienting the measurement antenna and for
determining the maximum likely emission amplitudes to facilitate
decisions pertaining to the necessity of adding additional attenuation
in the measurement system so as to prevent overdriving of components.
This data was not used for any analytical purposes. The lower (blue)
trace represents the measured RMS average emission level over one
hundred one-millisecond analyzer sweeps across the measurement band.
This is the data used to compare to the assumed interference threshold
for enhanced GPS receivers. The constant display line (green) at -117.5
dBm is used as the basis for comparing the measured data to the
theoretical enhanced GPS interference threshold.

All external measurement system parameters (e.g., amplifier gains, cable
loss, and antenna gain) are accounted for in the spectrum analyzer
display and are provided on each plot under the tag Ext PG located at
the top of the display. At some measurement locations, it was necessary
to add additional attenuation in the measurement system due to the
presence of relatively high-amplitude signals. In those cases where
additional external attenuation was required, the Ext PG value was
adjusted accordingly. Thus, the levels shown on the amplitude axis of
the spectrum analyzer plots represent the actual RMS average power as
measured in a 1 MHz bandwidth at the measurement system antenna.

In each of these plots, the horizontal axis represents frequency and the
vertical axis represents amplitude. For measurements in the GPS
frequency bands, a span of 25 MHz was used to encompass the 24 MHz
registered frequency band. For a 25 MHz span, each vertical graticule
line represents a 2.5 MHz deviation in frequency (25 MHz/10 graticule
lines). For the measurements performed in the 960-1160 MHz (ARNS) band,
a span of 50 MHz was used, the maximum that could be achieved within the
pass band of the pre-select filter. In these plots, each vertical
graticule line represents a frequency deviation of 5 MHz (50 MHz/10
graticule lines).

On the amplitude axis, each horizontal graticule line represents a 10 dB
decrement from the reference level amplitude shown in the upper
left-hand corner of the plot.

![](media/image66.png){width="6.0in" height="4.0in"}

Figure D-64. Ambient Emissions in GPS L1 Frequency Band Office Building
#1.

![](media/image67.png){width="6.0in" height="4.0in"}

Figure D-65. Ambient Emissions in GPS L2 Frequency Band Office Building
#1.

![](media/image68.png){width="6.0in" height="4.0in"}

Figure D-66. Ambient Emissions in GPS L5 Frequency Band Office Building
#1.

![](media/image69.png){width="6.0in" height="4.0in"}

Figure D-67. Ambient Emissions in 960-1010 MHz Frequency Band at Office
Building #1.

![](media/image70.png){width="6.0in" height="4.0in"}

Figure D-68. Ambient Emissions in 1010-1060 MHz Frequency Band at Office
Site #1.

![](media/image71.png){width="6.0in" height="4.0in"}

Figure D-69. Ambient Emissions in 1060-1110 MHz Frequency Band at Office
Site #1.

![](media/image72.png){width="6.0in" height="4.0in"}

Figure D-70. Ambient Emissions in 1110-1160 MHz Frequency Band at Office
Site #1.

![](media/image73.png){width="6.0in" height="4.0in"}

Figure D-71. Ambient Emissions in GPS L1 Frequency Band at Office Site
#2.

![](media/image74.png){width="6.0in" height="4.0in"}

Figure D-72. Ambient Emissions in GPS L2 Frequency Band at Office Site
#2.

![](media/image75.png){width="6.0in" height="4.0in"}

Figure D-73. Ambient Emissions in GPS L5 Frequency Band at Office Site
#2.

![](media/image76.png){width="6.0in" height="4.0in"}

Figure D-74. Ambient Emissions in 960-1010 MHz Frequency Band at Office
Site #2.

![](media/image77.png){width="6.0in" height="4.0in"}

Figure D-75. Ambient Emissions in 1010-1060 MHz Frequency Band at Office
Site #2.

![](media/image78.png){width="6.0in" height="4.0in"}

Figure D-76. Ambient Emissions in 1060-1110 MHz Frequency Band at Office
Site #2.

![](media/image79.png){width="6.0in" height="4.0in"}

Figure D-77. Ambient Emissions in 1110-1160 MHz Frequency Band at Office
Site #2.

![](media/image80.png){width="6.0in" height="4.0in"}

Figure D-78. Ambient Emissions in GPS L1 Frequency Band at Office Site
#3.

![](media/image81.png){width="6.0in" height="4.0in"}

Figure D-79. Ambient Emissions in GPS L2 Frequency Band at Office Site
#3.

![](media/image82.png){width="6.0in" height="4.0in"}

Figure D-80. Ambient Emissions in GPS L5 Frequency Band at Office Site
#3.

![](media/image83.png){width="6.0in" height="4.0in"}

Figure D-81. Ambient Emissions in 960-1010 MHz Frequency Band at Office
Site #3.

![](media/image84.png){width="6.0in" height="4.0in"}

Figure D-82. Ambient Emissions in 1010-1060 MHz Frequency Band at Office
Site #3.

![](media/image85.png){width="6.0in" height="4.0in"}

Figure D-83. Ambient Emissions in 1060-1110 MHz Frequency Band at Office
Site #3.

![](media/image86.png){width="6.0in" height="4.0in"}

Figure D-84. Ambient Emissions in 1110-1160 MHz Frequency Band at Office
Site #3.

![](media/image87.png){width="6.0in" height="4.0in"}

Figure D-85. Ambient Emissions in GPS L1 Frequency Band at Office Site
#4.

![](media/image88.png){width="6.0in" height="4.0in"}

Figure D-86. Ambient Emissions in GPS L2 Frequency Band at Office Site
#4.

![](media/image89.png){width="6.0in" height="4.0in"}

Figure D-87. Ambient Emissions in GPS L5 Frequency Band at Office Site
#4.

![](media/image90.png){width="6.0in" height="4.0in"}

Figure D-88. Ambient Emissions in 960-1010 MHz Frequency Band at Office
Site #4.

![](media/image91.png){width="6.0in" height="4.0in"}

Figure D-89. Ambient Emissions in 1010-1060 MHz Frequency Band at Office
Site #4.

![](media/image92.png){width="6.0in" height="4.0in"}

Figure D-90. Ambient Emissions in 1060-1110 MHz Frequency Band at Office
Site #4.

![](media/image93.png){width="6.0in" height="4.0in"}

Figure D-91. Ambient Emissions in 1110-1160 MHz Frequency Band at Office
Site #4.

![](media/image94.png){width="6.0in" height="4.0in"}

Figure D-92. Ambient Emissions in GPS L1 Frequency Band at Office Site
#5.

![](media/image95.png){width="6.0in" height="4.0in"}

Figure D-93. Ambient Emissions in GPS L2 Frequency Band at Office Site
#5.

![](media/image96.png){width="6.0in" height="4.0in"}

Figure D-94. Ambient Emissions in GPS L5 Frequency Band at Office Site
#5.

![](media/image97.png){width="6.0in" height="4.0in"}

Figure D-95. Ambient Emissions in 960-1010 MHz Frequency Band at Office
Site #5.

![](media/image98.png){width="6.0in" height="4.0in"}

Figure D-96. Ambient Emissions in 1010-1060 MHz Frequency Band at Office
Site #5.

![](media/image99.png){width="6.0in" height="4.0in"}

Figure D-97. Ambient Emissions in 1060-1110 MHz Frequency Band at Office
Site #5.

![](media/image100.png){width="6.0in" height="4.0in"}

Figure D-98. Ambient Emissions in 1110-1160 MHz Frequency Band at Office
Site #5.

![](media/image101.png){width="6.0in" height="4.0in"}

Figure D-99. Ambient Emissions in GPS L1 Frequency Band at Factory Site
#1.

![](media/image102.png){width="6.0in" height="4.0in"}

Figure D-100. Ambient Emissions in GPS L2 Frequency Band at Factory Site
#1.

![](media/image103.png){width="6.0in" height="4.0in"}

Figure D-101. Ambient Emissions in 960-1010 MHz Frequency Band at
Factory Site #1.

![](media/image104.png){width="6.0in" height="4.0in"}

Figure D-102. Ambient Emissions in 1010-1060 MHz Frequency Band at
Factory Site #1.

![](media/image105.png){width="6.0in" height="4.0in"}

Figure D-103. Ambient Emissions in 1060-1110 MHz Frequency Band at
Factory Site #1.

![](media/image106.png){width="6.0in" height="4.0in"}

Figure D-104. Ambient Emissions in 1110-1160 MHz Frequency Band at
Factory Site #1.

![](media/image107.png){width="6.0in" height="4.0in"}

Figure D-105. Ambient Emissions in GPS L1 Frequency Band at Factory Site
#2.

![](media/image108.png){width="6.0in" height="3.8048611111111112in"}

Figure D-106. Ambient Emissions in GPS L2 Frequency Band at Factory Site
#2.

![](media/image109.png){width="6.0in" height="4.0in"}

Figure D-107. Ambient Emissions in GPS L5 Frequency Band at Factory Site
#2.

![](media/image110.png){width="6.0in" height="4.0in"}

Figure D-108. Ambient Emissions in 960-1010 MHz Frequency Band at
Factory Site #2.

![](media/image111.png){width="6.0in" height="4.0in"}

Figure D-109. Ambient Emissions in 1010-1060 MHz Frequency Band at
Factory Site #2.

![](media/image112.png){width="6.0in" height="4.0in"}

Figure D-110. Ambient Emissions in 1060-1110 MHz Frequency Band at
Factory Site #2.

![](media/image113.png){width="6.0in" height="4.0in"}

Figure D-111. Ambient Emissions in 1110-1160 MHz Frequency Band at
Factory Site #2.

![](media/image114.png){width="6.0in" height="4.0in"}

Figure D-112. Ambient Emissions in GPS L1 Frequency Band at Factory Site
#3.

![](media/image115.png){width="6.0in" height="4.0in"}

Figure D-113. Ambient Emissions in GPS L2 Frequency Band at Factory Site
#3.

![](media/image116.png){width="6.0in" height="4.0in"}

Figure D-114. Ambient Emissions in GPS L5 Frequency Band at Factory Site
#3.

![](media/image117.png){width="6.0in" height="4.0in"}

Figure D-115. Ambient Emissions in 960-1010 MHz Frequency Band at
Factory Site #3.

![](media/image118.png){width="6.0in" height="4.0in"}

Figure D-116. Ambient Emissions in 1010-1060 MHz Frequency Band at
Factory Site #3.

![](media/image119.png){width="6.0in" height="4.0in"}

Figure D-117. Ambient Emissions in 1060-1110 MHz Frequency Band at
Factory Site #3.

![](media/image120.png){width="6.0in" height="4.0in"}

Figure D-118. Ambient Emissions in 1110-1160 MHz Frequency Band at
Factory Site #3.

APPENDIX E

RADIATED EMISSIONS MEASUREMENT DATA

The data plots recorded from the measurements of radiated emissions from
common consumer electronic/electrical devices are presented in this
appendix.

## In each of the spectrum analyzer plots presented in this Appendix, two measurement traces are shown. The lower (yellow) trace represents the background (ambient) emissions in the frequency band under examination with the DUT turned off. The upper (blue) trace represents the sum of the RMS average emissions radiated from the DUT and the existing background (ambient) emissions. A constant display line (green) is also shown in each plot. This is set to a level of -117.5 dBm to represent the received power equivalent to the UWB EIRP limit of -75.3 dBm/MHz at a distance of two meters. 

## 

## All external measurement system parameters (e.g., amplifier gains, cable loss, and antenna gain) are accounted for in the spectrum analyzer display and are provided on each plot under the tag Ext PG located at the top of the display.

In each of these plots, the horizontal axis represents frequency and the
vertical axis represents amplitude. A span of 25 MHz was used to
encompass the 24 MHz registered GPS frequency band. For a 25 MHz span,
each vertical graticule line represents a 2.5 MHz deviation in frequency
(25 MHz/10 graticule lines). On the amplitude axis, each horizontal
graticule line represents a 10 dB decrement from the reference level
amplitude shown in the upper left-hand corner of the plot. Note that
some of these plots utilize other than 10 dB per vertical division
(graticule line). This was done to facilitate better resolution of the
signals under examination. These plots are read the same way as
described previously except that each vertical line may represent a
deviation of 2, 3, or 5 dB from the reference level. The dB-per-division
scale, applicable to each plot, is shown in the upper left-hand margin.

An important consideration in the interpretation of this data is the
fact that the radiated spurious power captured by the measurement system
is actually the sum of the ambient emissions already present and those
spurious emissions introduced when the DUT is turned on. Since the
emissions under consideration in this study are often very close to the
ambient noise floor, the contribution of the noise floor to this sum can
be significant. Within this study, if the difference between the
measured ambient level and the corresponding radiated-plus-ambient level
is 3 dB, then the DUT emission amplitude level is interpreted as being
equivalent to the ambient level. Accordingly, if the difference between
the DUT radiated-plus-ambient emission level and the corresponding
ambient emission level is less than 3 dB, then the DUT emission level is
interpreted as being less than the ambient level. Emissions that are
more than 3 dB above the corresponding ambient level are attributed to
spurious emissions from the DUT.

![](media/image121.png){width="6.0in" height="4.0in"}

Figure E-119. Desktop Computer #1 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image122.png){width="6.0in" height="4.0in"}

Figure E-120. Desktop Computer #1 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image123.png){width="6.0in" height="4.0in"}

Figure E-121. Desktop Computer #1 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image124.png){width="6.0in" height="4.0in"}

Figure E-122. Desktop Computer #2 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image125.png){width="6.0in" height="4.0in"}

Figure E-123. Desktop Computer #2 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image126.png){width="6.0in" height="4.0in"}

Figure E-124. Desktop Computer #2 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image127.png){width="6.0in" height="4.0in"}

Figure E-125. Desktop Computer #3 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image128.png){width="6.0in" height="4.0in"}

Figure E-126. Desktop Computer #3 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image129.png){width="6.0in" height="4.0in"}

Figure E-127. Desktop Computer #3 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image130.png){width="6.0in" height="4.0in"}

Figure E-128. Laptop Computer #1 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image131.png){width="6.0in" height="4.0in"}

Figure E-129. Laptop Computer #1 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image132.png){width="6.0in" height="4.0in"}

Figure E-130. Laptop Computer #1 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image133.png){width="6.0in" height="4.0in"}

Figure E-131. Laptop Computer #2 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image134.png){width="6.0in" height="4.0in"}

Figure E-132. Laptop Computer #2 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image135.png){width="6.0in" height="4.0in"}

Figure E-133. Laptop Computer #2 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image136.png){width="6.0in" height="4.0in"}

Figure E-134. Laptop Computer #3 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image137.png){width="6.0in" height="4.0in"}

Figure E-135. Laptop Computer #3 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image138.png){width="6.0in" height="4.0in"}

Figure E-136. Laptop Computer #3 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image139.png){width="6.0in" height="4.0in"}

Figure E-137. Laptop Computer #4 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image140.png){width="6.0in" height="4.0in"}

Figure E-138. Laptop Computer #4 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image141.png){width="6.0in" height="4.0in"}

Figure E-139. Laptop Computer #4 Radiated Emissions in GPS L5 Frequency
Band.

**Note #1:** In this spectral plot, the ambient or background emission
level is shown as greater than the sum of the radiated emissions and the
background emissions in the highlighted frequency range. Although this
apparent inconsistency was not thoroughly examined, the most likely
explanation is as follows: the background measurement and the radiated
measurements were performed sequentially rather than simultaneously. The
ambient emission was higher when the background measurement was
performed than it was when the radiated measurement was made. This can
be attributed to one or more of the following phenomena. An antenna
rotation associated with the ambient transmitter (e.g., transmit antenna
was pointed in the direction of the test facility when the background
measurement was made, but pointed away during the radiated emissions
measurement) or fading due to the occurrence of multi-path signal
arrival at the measurement antenna.

![](media/image127.png){width="6.0in" height="4.0in"}

Figure E-140. Personal Digital Assistant (PDA) Radiated Emissions in GPS
L1 Frequency Band.

![](media/image128.png){width="6.0in" height="4.0in"}

Figure E-141. Personal Digital Assistant (PDA) Radiated Emissions in GPS
L2 Frequency Band.

![](media/image129.png){width="6.0in" height="4.0in"}

Figure E-142. Personal Digital Assistant (PDA) Radiated Emissions in GPS
L5 Frequency Band.

![](media/image142.png){width="6.0in" height="4.0in"}

Figure E-143. Pendant Transmitter Radiated Emissions in GPS L1 Frequency
Band.

![](media/image143.png){width="6.0in" height="4.0in"}

Figure E-144. Electric Drill #1 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image144.png){width="6.0in" height="4.0in"}

Figure E-145. Electric Drill #1 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image145.png){width="6.0in" height="4.0in"}

Figure E-146. Electric Drill #1 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image146.png){width="6.0in" height="4.0in"}

Figure E-147. Electric Drill #2 Radiated Emissions in GPS L1 Frequency
Band.

![](media/image147.png){width="6.0in" height="4.0in"}

Figure E-148. Electric Drill #2 Radiated Emissions in GPS L2 Frequency
Band.

![](media/image148.png){width="6.0in" height="4.0in"}

Figure E-149. Electric Drill #2 Radiated Emissions in GPS L5 Frequency
Band.

![](media/image149.png){width="6.0in" height="4.0in"}

Figure E-150. Electric Hairdryer #1 Radiated Emissions in the GPS L1
Frequency Band.

![](media/image150.png){width="6.0in" height="4.0in"}

Figure E-151. Electric Hairdryer #1 Radiated Emissions in the GPS L2
Frequency Band.

![](media/image151.png){width="6.0in" height="4.0in"}

Figure E-152. Electric Hairdryer #1 Radiated Emissions in the GPS L5
Frequency Band.

![](media/image152.png){width="6.0in" height="4.0in"}

Figure E-153. Electric Hairdryer #2 Radiated Emissions in the GPS L1
Frequency Band.

![](media/image153.png){width="6.0in" height="4.0in"}

Figure E-154. Electric Hairdryer #2 Radiated Emissions in the GPS L2
Frequency Band.

![](media/image154.png){width="6.0in" height="4.0in"}

Figure E-155. Electric Hairdryer #2 Radiated Emissions in the GPS L5
Frequency Band.

![](media/image155.png){width="6.0in" height="4.0in"}

Figure E-156. Electric Vacuum Cleaner Radiated Emissions in the GPS L1
Frequency Band.

![](media/image156.png){width="6.0in" height="4.0in"}

Figure E-157. Electric Vacuum Cleaner Radiated Emissions in the GPS L2
Frequency Band.

![](media/image157.png){width="6.0in" height="4.0in"}

Figure E-158. Electric Vacuum Cleaner Radiated Emissions in the GPS L5
Frequency Band.

[^1]: Letter from United States Department of Commerce, National
    Telecommunications and Information Administration/William T. Hatch
    to Federal Communications Commission, Office of Engineering
    Technology/Edmond J. Thomas, dated 13 February 2002 (hereinafter
    "NTIA Letter") at pp. 13 and 14.

[^2]: See NTIA Letter, Table 6.

[^3]: FCC 02-48, *Revision of Part 15 of the Commission's Rules
    Regarding Ultra-Wideband Transmission Systems*, First Report and
    Order, ET Docket 98-153, April, 2002, (hereinafter "UWB R&O").

[^4]: FCC 00-163, *Revision of Part 15 of the Commission's Rules
    Regarding Ultra-Wideband Transmission Systems*, Notice of Proposed
    Rulemaking, ET Docket No. 98-153, May 11, 2000, (hereinafter "UWB
    NPRM").

[^5]: See NTIA Special Publications 01-45 and 01-47, *Assessment of
    Compatibility Between Ultrawideband (UWB) Systems and Global
    Positioning System (GPS) Receivers,* February 2001 (initial report)
    and November 2001 (addendum), (hereinafter "NTIA Report" and "NTIA
    Report Addendum"), University of Texas at Austin Applied Research
    Laboratories, *Final Report Data Collection Campaign for Measuring
    UWB/GPS Compatibility Effects*, Feb. 26, 2001, Stanford University,
    *Potential Interference to GPS from UWB Transmitters Phase II Test
    Results*, March 16, 2001, and Johns Hopkins University/Applied
    Physics Laboratory, *Final Report UWB-GPS Compatibility Analysis
    Project*, March 8, 2001.

[^6]: NTIA Letter at page 2.

[^7]: ^?^ NTIA Letter at page 2.

[^8]: ARINC Research Corporation, *Navstar GPS Space Segment/Navigation
    User Interfaces*, Sept. 25, 1997, at page 13.

[^9]: Press Release from The White House, Office of the Vice President,
    "*Vice President Gore Announces New Global Positioning System
    Modernization Initiative*," January 25, 1999.

[^10]: Hegarty, C., and Van Dierendonck, A.J., "*Civil GPS/WAAS Signal
    Design and Interference Environment at 1176.45 MHz: Results of RTCA
    SC159 WG1 Activities.*"

[^11]: ITU-R Recommendation M.1477, *Technical and Performance
    Characteristics of Current and Planned Radionaviagation-Satellite
    Service (Space-to-Earth) and Aeronautical Radionavigation Service
    Receivers to Be Considered in Interference Studies in the Band
    1559-1610 MHz*, 2000, (hereinafter "ITU-R M.1477").

[^12]: RTCA/DO-229B*, Minimum Operational Performance Standard for
    GPS/Wide Area Augmentation System Airborne Equipment*, January,
    1996.

[^13]: See ITU-R M.1477.

[^14]: See NTIA Report Addendum, Tables 2-4 through 2-6.

[^15]: See UWB R&O, Table 1 and NTIA Letter, Table 1.

[^16]: See NTIA Letter at p 10.

[^17]: See UWB R&O at par. 103 and NTIA Letter at p.10.

[^18]: See NTIA Letter, Tables 2-5.

[^19]: See UWB R&O, tables 3-5. Note: Although the receiver
    susceptibility threshold shown in these tables is -114.5 dBm/MHz,
    paragraph 111 specifies a 3 dB uncertainty margin that makes the
    effective receiver susceptibility threshold equal to -117.5 dBm/MHz.

[^20]: ^?^ See NTIA Letter, Table 2.

[^21]: See UWB R&O at paragraph 99 and NTIA Letter at p. 8.

[^22]: 47 C.F.R. Chapter 15, Part 15, Subpart B, § 15.109.

[^23]: 47 C.F.R. Chapter 15, Part 15, Subpart B, § 15.13.

[^24]: NTIA Letter at p. 9, and UWB R&O at par. 101.