**RESPONSES OF GPS SOURCE INC. TO NTIA QUESTIONS**

**FOR THE**

**Special Meeting of the IRAC Regarding GPS Re-Radiators,**

**October 28, 2005**

# Overview:

GPS re-radiators have proven invaluable in a wide variety of
applications for both government and commercial users alike. Operation
of these devices, however, has been limited to certain experimental
applications. GPS Source, Inc. ("GPSS")[^1] and other interested parties
are now engaged in an effort to establish a balanced regulatory regime
that restricts device operation to a limited class of eligible users,
ensures proper installation in controlled locations, and prevents
harmful interference to licensed operations. The precise regulatory
requirements of such a regime presumably will involve some form of
site-licensing and equipment authorization, using the criteria developed
by the National Telecommunications and Information Administration
("NTIA") (if necessary, as modified through the Interdepartment Radio
Advisory Committee ("IRAC") process and industry input) as the technical
standard with which all device deployments and operations must
conform.[^2] The procedural mechanics for establishing or otherwise
authorizing such a regime within the Federal Communications Commission's
("FCC") rules ultimately must be decided by the agency itself. In all
events, however, the existing practice of relying upon experimental
licensing authorization under Part 5 of the FCC rules is both
inefficient and incomplete, in major part because it does not address
the equipment authorization process.

The Chairman of the IRAC noticed a special meeting for October 28, 2005,
to "receive information on GPS RE-Radiators." In preparation for that
meeting, NTIA posed a number of questions to GPSS and other interested
parties. Those questions are reprinted below, along with GPSS's
responses.

[NTIA Questions and Responses:]{.underline}

*Question 1*: What are the applications of your device(s)?

The following responses are based upon GPSS's experience and do not
necessarily reflect the customer or sales practices and experiences of
other GPS re-radiator manufacturers. Accordingly, the following data
probably under-reports the scope of GPS re-radiator usage in the U.S.

a)  ***Federal Government applications.***

***Answer 1(a)*:** GPS re-radiators have been purchased from GPSS by
several Federal Government Agencies for use in various applications. The
following is a list of frequent applications and examples of these
Federal Government Agencies. The list is not exhaustive:

-   **[Examples of Currently Fielded Applications]{.underline}**:

    -   Military and government maintenance and testing facilities.

    -   Military and government research and development facilities.

    -   Military and government training facilities.

    -   Maintaining "hot" GPS status for military aircraft and Special
        Forces units.

    -   Indoor initialization of "cold" GPS receivers on National
        Weather Service weather balloons prior to outdoor release.

-   **[Specific Examples of Federal Government Agencies]{.underline}**:

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-   **NOAA\\NWS** (122 units).

-   **Department of Defense** (111 units):

    -   **USAF/ANG** (41 units).

    -   **US Army\\Army Corps of Engineers** (40 units).

    -   **USN** (24 units).

    -   **USCG** (6 units).

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-   **Federal Aviation Administration** (4 units).

-   **US Secret Service** (4 units).

-   **FBI** (3 units).

-   **NASA** (3 units).

b)  ***State/Local Government applications.***

> ***Answer 1(b)*:** GPS re-radiators have been purchased from GPSS by
> several State/Local Government Agencies for use primarily in
> non-mobile, indoor GPS-enabled Public Safety and Public Transit
> applications. The following is a list of frequent applications and
> examples

-   **[Examples of Currently Fielded Applications (109
    units)]{.underline}**:

    -   Operation of public transit Automatic Vehicle Location systems
        at passenger terminals

    -   Maintaining "hot" status for Emergency Vehicle Navigation
        systems

    -   Maintaining "hot" status for Emergency Vehicle Traffic Light
        Preemption systems

c)  ***Private/Commercial applications.***

***Answer 1(c)*:** GPS re-radiators have been purchased from GPSS by
numerous Private/Commercial entities for use in many different
applications. The following is a list of frequent applications and
several examples of Private/Commercial entities. The list is not
exhaustive:

-   **[Examples of Currently Fielded Applications]{.underline}**:

    -   Manufacturing facilities for GPS-capable products (GPS
        receivers, cell phones, automobiles, aircraft, etc.).

    -   Maintenance and testing facilities.

    -   Research and development facilities.

    -   Training facilities.

    -   GPS customer service centers.

    -   Retail centers for demonstration of GPS products.

    -   Applications that require high precision clocks or time
        (communications).

-   **[Specific Examples of Private/Commercial Entities]{.underline}**:

    -   **Defense Department Contractors** (102 units).

    -   **USGPS IC Members** (68 units).

    -   **Civil Aviation** (60+ units).

    -   **Cellular** (40+ units).

    -   **Broadcast Communications** (25+ units).

    -   **Survey** (30+ units).

    -   **Dealers/Distributors** (300+ units).

*Question 2*: What are the benefits of those applications to safety
(lives saved)/commerce (money saved)/convenience (time saved)?

***Answer 2*:** GPSS is not versed in the detailed rationale for the
acquisitions made by any of the referenced customers. Nor does GPSS
claim to understand exactly how GPS re-radiator systems specifically
improve or enable those customers' day-to-day operations. The nature and
extent of such benefits are best addressed by those individual experts
who expend significant capital and resources to procure, install, and
operate GPS re-radiating devices. To the best of our understanding,
however, the following are some examples of the utility of GPS
re-radiating products:

-   Military Flight line Maintenance and Operations

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-   Reduced maintenance time and costs by enabling trouble shooting,
    repair, and testing of aircraft systems within maintenance
    facilities when it is impractical to conduct such activities
    elsewhere (e.g., depot level maintenance facilities, Naval aircraft
    carrier hanger bays, hardened aircraft revetments, etc.).

-   More efficient maintenance practices result in increased aircraft
    ready rates.

-   Reduced response times for aircraft on alert status.

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-   Civil Aviation Production and Maintenance

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-   Enables testing, trouble shooting and repair of aircraft systems
    when aircraft may not be moved due to other maintenance or other
    aircraft.

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-   Public Safety

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-   Elimination of delay in traffic light preemption systems results in
    significantly improved safety in route and in reduced response times
    (accidents at controlled intersections jeopardize the lives of
    emergency responders and citizens).

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-   Commercial GPS Industry

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-   Enabling of "full system" testing in manufacturing environment
    results in improved efficiencies and product quality.

-   Enabling of indoor operation at customer service call centers
    results in significantly improved customer service.

-   Enabling of indoor training improves customer experience and
    performance of customer support staff.

-   Enabling of product demonstration in GPS product retail centers
    improves customer product selection experience.

-   Enabling of R&D lab testing results in significantly reduced
    development costs and improved product quality.

***Question 3*: Can the information provided by those re-radiator
applications be obtained in any other way?**

***Answer 3*:** In certain of the preceding examples, there may be other
means available to perform the intended function, such as GPS simulators
or the distribution of the GPS signal by way of coaxial cable network.
However, in many of the preceding examples, these alternatives are
either impractical or they can not accomplish the desired function. For
example, cable drops in large aircraft production and maintenance
facilities are impractical and would not allow a full system test, e.g.,
antenna system is not tested. Cable connections and GPS simulators are
also impractical for applications where GPS re-radiators are used to
maintain "hot" status for rapid dispatch of public safety vehicles or
military aircraft.

# 

# *Question 4*: What is the nature of your device(s)?

a)  ***Are they Fixed (permanent), Fixed (temporary) or Mobile**?*

***Answer 4(a)*:** GPSS supports the authorization of fixed-permanent
and fixed-temporary applications. GPSS, however, believes there may be
limited applications for mobile use that would serve the public
interest, such as DOD applications using very low power systems
operating in armored vehicles on large training or testing facilities.

b)  ***What levels do they emit (Power output and antenna
    characteristics)?***

***Answer 4(b)*:** GPSS supports authorization of only GPS re-radiator
systems that have transmitter units with the capability to monitor and
control radiated power levels[^3] so as to ensure compliance with the
NTIA criteria. Although a GPSS proposed system would allow and encourage
operators to reduce the radiated levels to the minimum level required
for proper system operation, the proposed system would never allow ERP
levels in excess of NTIA criteria.

GPSS proposes two models for sale and installation of GPS re-radiator
systems:

-   A "standard" re-radiator system that is factory calibrated and
    permanently set for an ERP of -140 dBm at 100ft, with no allowance
    for attenuation of building materials or for dimensions of the
    building.

-   A "custom install" system that would allow for an approved installer
    to adjust power levels for proper system operation and for
    compliance with NTIA criteria. However, once set by the installer,
    the system power level would be automatically monitored and
    controlled to maintain the power level for compliance with NTIA
    criteria.

The re-radiator transmitter unit proposed in both of the above models
should also include a fixed transmitter antenna so that antenna gain may
be accounted for in the power monitor and control function and so that
additional gain stages may not be added after the power control and
monitor function.

c)  ***What means have you used to determine the signal output level
    (measurement/measurement method vs. calculation/calculation
    method)?***

***Answer 4(c)*:** Formerly, GPS re-radiating system output levels have
been determined by measurement of the system gain prior to delivery and
installation, calculation of signal levels using standard propagation
models, and by assuming nominal GPS satellite signal levels at the
receiver antenna (-130dBm). Such methods can result in errors of several
dB in the radiated levels.

GPSS supports GPS re-radiating systems that have transmitter units with
the capability to automatically monitor and control radiated power
levels so as to ensure compliance with NTIA criteria. Transmitter units
would be calibrated prior to delivery and Effective Radiated Power (ERP)
levels would be set, either at the factory or by an approved installer,
according to calculations as described in item 7 of the NTIA criteria.

d)  ***What ability does the user have to alter these
    characteristics?***

***Answer 4(d)*:** Once the ERP level has been set as described in
***4(c)***, the re-radiator system would not permit adjustment to ERP
levels that would exceed the NTIA criteria. As a result of the proposed
automated power monitor and control function, attempts to increase
radiated power levels by the reduction of coaxial cable lengths or by
the introduction of additional amplification stages would be compensated
for in the transmitter unit. GPS re-radiator systems that include a
transmitter power monitor/control function and a fixed transmitter
antenna help deter and prevent alteration by the user.

***Question 5*: What regulatory scheme do you believe would be
appropriate to ensure that there was no interference to GPS?**

a)  ***Would you propose licensing vs non-licensed use?***

***Answer 5(a)*:** GPSS supports the establishment of a reasonable,
practical and effective "authorization" regime, administered by the FCC
for non-governmental entities and by the NTIA for governmental entities,
covering the manufacturing, marketing and use of GPS re-radiation
products. GPSS understands that site-based licensing may be the most
effective regime for ensuring compliance and control over actual use,
and might better ensure prior IRAC coordination, should such action be
required for GPS re-radiator installations. Whether and how such a
regime (or similar) can be expeditiously implemented under the FCC rules
is a question for the FCC to determine, as it involves such
considerations as administrative convenience. However, GPSS supports
making the authorization process as least burdensome as practical, while
still ensuring that only eligible users whose deployments meet an agreed
upon set of criteria are able to deploy and operate these products. In
all events, the existing practice of relying upon experimental licensing
authorization under Part 5 of the FCC rules is impractical because of
the use limitations and insufficient because it does not address
equipment authorization.

b)  ***If you propose licensing, what process should be used and what
    criteria should be used to evaluate proposals?***

***Answer 5(b)*:** As indicated, in the context of non-governmental
users, GPSS suspects that whatever authorization scheme(s) the FCC could
and should pursue -- be it rule-based authorization, site-based
licensing, blanket licensing, registration or some other form -- is
probably best decided by the FCC itself, and is likely to be dictated by
the existing structure of the FCC rules. Regardless of which process
ultimately is adopted, GPSS supports using the existing criteria
developed by the NTIA (if necessary, as modified through the IRAC
process and industry input) as the foundation technical criteria against
which all device deployments and operations would be evaluated. Further,
GPSS is eager to work with any and all interested parties and agencies
to further refine the NTIA criteria and/or develop new industry criteria
for specific applications.

c)  ***If you proposed non-licensed use, what approach would you propose
    to deal with the prohibition on non-licensed use in the current
    rules (waiver, rule change. etc.)?***

***Answer 5(c*):** Not applicable.

d)  ***Would you limit the sales, installation and use to specific
    groups? If so, which groups?***

***Answer 5(d)*:** Yes, GPSS supports limiting sales, installation and
use to the following groups:

1.  Government agencies, including Federal, State and local government
    agencies, including law enforcement, fire and rescue organizations
    under the auspices of state and local government.

2.  Contractors operating under contract with the various agencies of
    the Federal government, including the Department of Defense or the
    military Department, including subcontractors and system
    integrators.

3.  Companies in the military and civilian aviation industry, including
    aircraft and avionics manufacturers and maintenance facilities.

4.  Manufacturers of GPS chipsets and integrators of such chipsets into
    other equipment.

5.  Manufacturing, production and test facilities where GPS is an
    integral part of the finished product.

6.  Commercial GPS equipment manufacturers and GPS product sales outlets
    or distribution points for the purpose of demonstrating commercial
    GPS products.

7.  Owners of indoor public transportation (e.g., train, subway) or
    parking facilities where repeaters could enable E911 services via
    access to GPS or AGPS service where it is otherwise unavailable.

8.  Members of the U.S. GPS Industry Council not included in the
    foregoing categories.

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e)  ***What emission limits should be applied to the devices?***

***Answer 5(e)*:** GPSS supports limitations on intentional emissions in
the GPS band(s) as defined by the NTIA criteria.

f)  ***How can the location of the devices be limited to ensure that
    there isn't interference to the general public?***

***Answer 5(f)*:** GPSS believes that an effectively managed regulatory
regime that is not overly burdensome, which includes equipment
authorizations based the current NTIA criteria with certain additional
GPS re-radiator system functional requirements, limitations on eligible
users, and proper installation and operational criteria will serve to
prevent harmful interference to the general public.

g)  ***Can the locations be entered into an on-line database?***

***Answer 5(g)*:** It seems that GPS re-radiator installations could
easily be entered into an on-line database, regardless of the
authorization scheme applied. If site-based licensing is adopted, then
the coordinates for non-government installations presumably would be
entered into the FCC's ULS database. The same result could be rendered
through a registration scheme. In addition, to the extent IRAC
coordination is required, deployment locations would be recorded and
located in NTIA files.

***Question 6*: Have you considered the use of leaky coaxial cable to
distribute the re-radiated signal?**

***Answer 6*:** Leaky coaxial cable as a means for distribution of the
re-radiated signal is not practical as it results in an effective
"smearing" of the GPS code phase correlation peaks, making it nearly
impossible for the GPS receiver to measure precise satellite
pseudo-ranges and consequently impedes the generation of a position fix.

***Question 7*: What is the bandwidth of the re-radiated GPS signal?**

***Answer 7*:** GPSS supports the requirement for limitations on the
re-radiated signal bandwidth. The re-radiating system bandwidth should
be sufficient to pass both civilian C\\A and military P codes. The
re-radiating system should have a dual frequency response for
applications that require both L1 (1575.42MHz) and L2 (1227.6MHz) band
operation. GPSS supports limitations on the re-radiated signal bandwidth
for both of these bands. Applications that do not require L2 band
operation should be limited to operation in the L1 band only.

***Question 8*: NTIA has developed rules to accommodate a specific use
of GPS re-radiators (e.g., fixed, use for testing purposes only,
received power limit at a specified distance). What are your thoughts on
the NTIA GPS re-radiator rules?**

***Answer 8*:** GPSS supports the use of the existing NTIA criteria as a
foundation for criteria governing equipment authorization. However, in
order to further reduce the potential for interference with other GPS
equipment operators, GPSS supports the inclusion of additional
re-radiator product requirements as follows:

-   GPS re-radiator transmitter units shall include automated ERP
    monitor and control functionality. This feature is necessary to
    ensure that the systems do not exceed NTIA criteria as a result of
    installation variables, system variations, or user tampering.

-   GPS re-radiator transmitter units shall include a fixed antenna so
    as to inhibit the introduction of additional amplification stages
    after the proposed ERP monitor and control functionality.

-   GPS re-radiator systems shall limit frequency bandwidth and out of
    band emissions.

-   GPS re-radiator systems shall include provisions for the detection
    and prevention of conditions that result in system oscillations.

GPSS is eager to work with any and all interested parties and agencies
to further refine the NTIA criteria and/or develop new industry criteria
for specific applications.

[^1]: GPS Source, Inc. is a Pueblo, Colorado based company that
    manufactures and sells various GPS-related components and services.
    Its principals and employees have extensive experience in the GPS
    industry, dating back to the late 1980s. This experience includes
    employment at leading GPS equipment manufacturers. GPS Source, Inc.
    customers include various federal government agencies and
    installations, government contractors and leading GPS equipment
    manufacturers.

[^2]: The NTIA criteria referred to herein are those technical criteria
    now incorporated in Section 8.3.28 of the NTIA Manual. US Department
    of Commerce, National Telecommunications and Information
    Administration, Doc. 34350/1, Ref. Doc. 34284/1, Addition of Section
    8.3.28, USE OF DEVICES THAT RE-RADIATE SIGNALS RECEIVED FROM THE
    GLOBAL POSITIONING SYSTEM, to the NTIA Manual of Regulations and
    Procedures for Federal Radio Frequency Management. Hereinafter
    referred to as "NTIA criteria."

[^3]: GPSS. has filed for patent rights for GPS re-radiating systems
    that include transmitter power monitor and control function.