January 28, 1999

Ms. Regina M. Keeney

Chief of the International Bureau

Federal Communications Commission

Washington, D.C. 20554

Dear Ms. Keeney:

The National Telecommunications and Information Administration on behalf
of the Executive Branch Agencies, has approved the release of two draft
proposals and one revision of a preliminary view for WRC-2000.

The first proposal concerns agenda item 1.9 and addresses the issue of
the Mobile Satellite Service (MSS) in the band 1559-1567 MHz.

The second proposal addresses agenda item 1.15.2. This agenda item
considers the addition of the space-to-space direction to the
radionavigation-satellite service (RNSS) allocations in the bands 1 215
-1 260 and 1 559 - 1610 MHz. The goal of this proposal is to provide an
allocation for space-to-space use for (RNSS), which will ensure the
protection of space-based RNSS receivers.

We have also revised our preliminary view for agenda item 1.9 concerned
with the proposal of an allocation for mobile satellite in 1559-1567 MHz
band. Our preliminary view opposes any mobile satellite allocation in
the 1559-1610 MHz band, and recommends suppression of Resolution 220.
The revised document better states our reasons for this position. We
have included two versions of this preliminary view, one version with
edit markings and one version without the edit markings.

> Sincerely,
>
> *Original Signed*
>
> William T. Hatch
>
> Acting Associate Administrator
>
> Office of Spectrum Management

Enclosures

**United States of America**

**(Draft) Proposals for the Work of the Conference**

# Proposals for Agenda Item 1.9

## to take into account the results of ITU-R studies in evaluating the feasibility of an allocation in the space-to-Earth direction to the mobile-satellite service in a portion of the 1 559 ‑ 1 567 MHz frequency range, in response to Resolutions 213 and 220 (WRC-97)

**Background:** The frequency range under consideration, 1 559 to 1 567
MHz, is allocated on a co-primary basis to Radionavigation Satellite
Service (RNSS) (space to Earth) and Aeronautical Radionavigation Service
(ARNS.) Additionally, the band is allocated to the Fixed Service (FS) in
some countries.

There are millions of RNSS receivers in use today for a wide range of
applications, including safety-of-life-critical navigation on land, at
sea, and in the air. Today, most of these receivers operate with the
Global Positioning System (GPS), an important element of the Global
Navigation Satellite System (GNSS) that operates in the 1 559 - 1 610
MHz band.

GPS provides position and time information to users by means of one-way
transmissions using RNSS (space-to-Earth) allocations. GPS is
information technology that uses systems of hardware and software, as
well as information (time and ephemeris) transmitted from satellites to
provide derived information to the user.

GLONASS and GPS are established elements of the International Civil
Aviation Organization (ICAO) GNSS, operating in the band 1 559 - 1 610
MHz. These systems are accepted by the ICAO Council for use in
international civil aviation. ICAO is currently developing Standards and
Recommended Practices for international application in civil aviation.
The GNSS will be used during all phases of flight, including precision
approaches and landing, and under all weather conditions. The latter
places extensive requirements on the performance characteristics of the
system. The aeronautical use of RNSS is recognized in the Radio
Regulations as a safety-of-life application. GPS is the sole basis for
the formation of International Atomic Time and Coordinated Universal
Time (UTC) by the International Bureau of Weights and Measures. GPS is
also the primary means by which clocks are synchronized within
telecommunications networks for Time Division Multiple Access
transmissions. Time and frequency functions are or will be available on
other RNSS systems.

As Resolution **220 (WRC-97)** recognizes RNSS and ARNS systems are
evolutionary and other types of GNSS are under development for operation
in the band 1 559 - 1 610 MHz. There are both aeronautical and
non-aeronautical safety-of-life services in the 1 559 - 1 610 MHz band,
and it is well established that there is an essential need to protect
systems operating in the ARNS and RNSS.

The core signal structures of the MSS and the RNSS and ARNS are
fundamentally different: MSS uses a two-way signal while ARNS and RNSS
transmits a weak, receive-only signal. Having systems from a
radiocommunication service operate on a co-primary, co-frequency basis
in the 1 559 - 1 610 MHz band would limit ARNS and RNSS operators\'
flexibility to adjust their spectrum usage, and would hamper efforts to
develop a GNSS that is capable of meeting evolving international needs
and of providing adequate protection for international civil use
worldwide.

Studies conducted in the ITU-R indicate the incompatibility of the MSS
(space-to-Earth) and ARNS and RNSS in any portion of the 1 559 - 1 567
MHz band. Not only do MSS signals have the potential to cause
significant interference to ARNS and RNSS, but GNSS pseudolites and
proposed new RNSS systems also have the potential to cause significant
interference to the MSS (space-to-Earth).

**Proposal:**

USA/ /

NOC

> The United States proposes that no allocation be made to the Mobile
> Satellite Service in the 1559-1567 MHz band.
>
> **Reasons**: The mobile satellite service is not compatible with RNSS
> and ARNS use of the 1559-1567 MHz band.

USA/ /

SUP

> **Reasons:** Studies performed by the ITU-R show that MSS systems are
> incompatible with GNSS; therefore, sharing of the band 1559-1567 MHz
> is not feasible. These studies satisfy the requirement of Resolution
> 220; therefore Res. 220 should be deleted.

**United States of America**

**(Draft) Proposals for the Work of the Conference**

# Proposals for Agenda Item 1.15.2

## to consider the addition of the space-to-space direction to the radionavigation-satellite service allocations in the bands 1 215 -1 260 and 1 559 - 1610 MHz

**Background:** Radionavigation-Satellite Service (RNSS) systems such as
the Global Positioning System and Global Navigation Satellite System are
primarily being used in the space-to-Earth direction to provide service
to terrestrial users. These systems are, however, also increasingly
being used in the space-to-space direction by spaceborne users for such
applications as spacecraft three-dimensional positioning and velocity
determination; three-axis attitude control; precise time
synchronization; precision orbit determination, and atmospheric science.
The use of RNSS signals is presently protected only through a
space-to-Earth allocation in the 1 215 - 1 260 and 1 559 - 1 610 MHz
bands. Recognizing current and future operational usage of spaceborne
RNSS receivers for scientific and commercial applications, it is
important to add the space-to-space direction to the existing RNSS
allocations so that these uses can be taken into consideration when
changes to the use of these bands are contemplated.

Interference studies have been conducted to assess the sensitivity of
spaceborne RNSS receivers to interference from radiolocation, Earth
exploration-satellite (active), space research (active), fixed, mobile
and aeronautical radionavigation services in the 1 215 - 1 260 MHz band;
from the aeronautical radionavigation and fixed services in the 1 559 -
1 610 MHz band; and also their sensitivity to intra-service interference
between radionavigation satellite service systems in these two bands.

The ITU-R has concluded that the addition of a space-to-space direction
to the 1 215 - 1 260 MHz and 1 559 - 1 610 MHz RNSS bands will not cause
any additional interference to other services since it involves no
change to the space-to-Earth transmissions.

Studies demonstrate that RNSS spaceborne receivers can operate
satisfactorily in the presence of interference caused by systems in
other services as well as other RNSS systems. Potential interference
from services in adjacent bands was also examined.

Existing coordination procedures are adequate for space-to-space
operations.

Proposal

+---------+-------------------+-------------------+-------------------+
|         | **MHz\            |                   |                   |
|         | 1 215 -- 1 260**  |                   |                   |
+---------+-------------------+-------------------+-------------------+
|         | Allocation to     |                   |                   |
|         | Services          |                   |                   |
+---------+-------------------+-------------------+-------------------+
|         | Region 1          | Region 2          | Region 3          |
+---------+-------------------+-------------------+-------------------+
| USA/ /  | **1 215-1 240**   |                   |                   |
|         | EARTH             |                   |                   |
| MOD     | EXPL              |                   |                   |
|         | ORATION-SATELLITE |                   |                   |
|         | (active)          |                   |                   |
|         |                   |                   |                   |
|         | RADIOLOCATION     |                   |                   |
|         |                   |                   |                   |
|         | RADIONAV          |                   |                   |
|         | IGATION-SATELLITE |                   |                   |
|         | (space-to-Earth)  |                   |                   |
|         |                   |                   |                   |
|         | >                 |                   |                   |
|         |  (space-to-space) |                   |                   |
|         |                   |                   |                   |
|         | SPACE RESEARCH    |                   |                   |
|         | (active)          |                   |                   |
|         |                   |                   |                   |
|         | > S5.329  S5.33   |                   |                   |
|         | 0  S5.331  S5.332 |                   |                   |
+---------+-------------------+-------------------+-------------------+
| USA/ /  | **1 240-1 260**   |                   |                   |
|         | EARTH             |                   |                   |
| MOD     | EXPL              |                   |                   |
|         | ORATION-SATELLITE |                   |                   |
|         | (active)          |                   |                   |
|         |                   |                   |                   |
|         | RADIOLOCATION     |                   |                   |
|         |                   |                   |                   |
|         | RADIONAV          |                   |                   |
|         | IGATION-SATELLITE |                   |                   |
|         | (space-to-Earth)  |                   |                   |
|         |                   |                   |                   |
|         | >                 |                   |                   |
|         |  (space-to-space) |                   |                   |
|         |                   |                   |                   |
|         | SPACE RESEARCH    |                   |                   |
|         | (active)          |                   |                   |
|         |                   |                   |                   |
|         | Amateur           |                   |                   |
|         |                   |                   |                   |
|         | S5.329  S5.3      |                   |                   |
|         | 30  S5.331  S5.33 |                   |                   |
|         | 2  S5.334  S5.335 |                   |                   |
+---------+-------------------+-------------------+-------------------+

> **Reasons:** Provide an allocation for space-to-space use for RNSS,
> which will ensure the protection of space-based RNSS receivers.

+---------+-------------------+-------------------+-------------------+
|         | **MHz\            |                   |                   |
|         | 1 559 -- 1 610**  |                   |                   |
+---------+-------------------+-------------------+-------------------+
|         | Allocation to     |                   |                   |
|         | Services          |                   |                   |
+---------+-------------------+-------------------+-------------------+
|         | Region 1          | Region 2          | Region 3          |
+---------+-------------------+-------------------+-------------------+
| USA/ /  | *                 |                   |                   |
|         | *1 559 -- 1 610** |                   |                   |
| MOD     | AERONAUTICAL      |                   |                   |
|         | RADIONAVIGATION   |                   |                   |
|         |                   |                   |                   |
|         | RADIONAV          |                   |                   |
|         | IGATION-SATELLITE |                   |                   |
|         | (space-to-Earth)  |                   |                   |
|         |                   |                   |                   |
|         | >                 |                   |                   |
|         |  (space-to-space) |                   |                   |
|         |                   |                   |                   |
|         | S5.341 S5.355     |                   |                   |
|         | S5.359 S5.363     |                   |                   |
+---------+-------------------+-------------------+-------------------+

> **Reasons:** Provide an allocation for space-to-space use for RNSS,
> which will ensure the protection of space-based RNSS receivers.

## UNITED STATES

## PRELIMINARY VIEW

**WRC-2000** **AGENDA ITEM 1.9:** *to* *take into account the results of
ITU-R studies in evaluating the feasibility of an allocation in the
space-to-Earth direction to the mobile-satellite service (MSS)* *in a
portion of the 1 559 ‑ 1 567 MHz frequency range, in response to
Resolutions **213** **(WRC-97)** and **220 (WRC-97)***

[ISSUE]{.underline}: Mobile-Satellite Service (MSS) downlink at
1559-1567 MHz

[BACKGROUND]{.underline}: The band 1559-1610 MHz is allocated to
Radionavigation Satellite Service (RNSS) and the Aeronautical
Radionavigation Service (ARNS). An objective of the United States, as
well as the International Civil Aviation Organization (ICAO), is the
implementation of a global navigation satellite system (GNSS) that can
support aeronautical safety in all phases of flight. The implementation
of GNSS will require use of the 1559-1610 MHz band, which is the sole
band currently identified to meet present and future requirements of
GNSS and its augmentations. A principal component of GNSS operating in
this band today is Global Position System (GPS), a navigation satellite
constellation providing a worldwide free-of-charge utility that is being
used increasingly for critical radionavigation, geolocation and timing
functions. GPS will be an element of GNSS. There are many types of GPS
receivers and applications, including aeronautical radionavigation for
all phases of flight, maritime, and uses on land such as surveying,
automobiles and scientific investigations. Systems that augment GPS in
critical applications are developing. Some of these systems are planned
to operate using frequencies in the lower end of the 1559-1610 MHz band.
These systems would be blocked by a Mobile-Satellite Service (MSS)
allocation. In addition, there are new RNSS systems being proposed that
would operate in the 1559-1567 MHz band, such as the European Space
Agency\'s, European Navigation Satellite System.

WRC-97 adopted RES 220 in response to a proposal to add an allocation to
the 1559-1567 MHz band for the Mobile-Satellite Service. ITU-R WP8D has
been tasked with performing studies to determine if sharing between MSS
and ARNS and RNSS is feasible. The ITU Radio Regulation S4.10 states
"Members recognize that the safety aspects of radionavigation and other
safety services require special measures to ensure their freedom from
harmful interference; it is necessary therefore to take this factor into
account in the assignment and use of frequencies." The United States is
working in WP8D and ICAO to document GPS requirements and the
requirements for new systems in this band. Studies are largely completed
to determine interference requirements of a broad range of GPS receivers
covering safety and non-safety applications.

Further work is planned for the next WP8D meeting.

[PRELIMINARY VIEW]{.underline}: Based on present and future requirements
of the radionavigation satellite services and in particular civil
aviation, there is a need to retain the 1559-1610 MHz band for exclusive
use by ARNS and the RNSS. Accordingly, the United States opposes any
proposed MSS allocation in the 1559-1610 MHz band, and recommends
suppression of Res. 220. **(19Jan99)**

***The following is the same preliminary view with the strikeout and
underline markings removed.***

**WRC-2000 AGENDA ITEM 1.9:** *to* *take into account the results of
ITU-R studies in evaluating the feasibility of an allocation in the
space-to-Earth direction to the mobile-satellite service (MSS) in a
portion of the 1 559 ‑ 1 567 MHz frequency range, in response to
Resolutions **213** **(WRC-97)** and **220 (WRC-97)***

[ISSUE]{.underline}: Mobile-Satellite Service (MSS) downlink at
1559-1567 MHz

[BACKGROUND]{.underline}: The band 1559-1610 MHz is allocated to
Radionavigation Satellite Service (RNSS) and the Aeronautical
Radionavigation Service (ARNS). An objective of the United States, as
well as the International Civil Aviation Organization (ICAO), is the
implementation of a global navigation satellite system (GNSS) that can
support aeronautical safety in all phases of flight. The implementation
of GNSS will require use of the 1559-1610 MHz band, which is the sole
band currently identified to meet present and future requirements of
GNSS and its augmentations. A principal component of GNSS operating in
this band today is Global Position System (GPS), a navigation satellite
constellation providing a worldwide free-of-charge utility that is being
used increasingly for critical radionavigation, geolocation and timing
functions. GPS will be an element of GNSS. There are many types of GPS
receivers and applications, including aeronautical radionavigation for
all phases of flight, maritime, and uses on land such as surveying,
automobiles and scientific investigations. Systems that augment GPS in
critical applications are developing. Some of these systems are planned
to operate using frequencies in the lower end of the 1559-1610 MHz band.
These systems would be blocked by a Mobile-Satellite Service (MSS)
allocation. In addition, there are new RNSS systems being proposed that
would operate in the 1559-1567 MHz band, such as the European Space
Agency\'s, European Navigation Satellite System.

WRC-97 adopted RES 220 in response to a proposal to add an allocation to
the 1559-1567 MHz band for the Mobile-Satellite Service. ITU-R WP8D has
been tasked with performing studies to determine if sharing between MSS
and ARNS and RNSS is feasible. The ITU Radio Regulation S4.10 states
"Members recognize that the safety aspects of radionavigation and other
safety services require special measures to ensure their freedom from
harmful interference; it is necessary therefore to take this factor into
account in the assignment and use of frequencies." The United States is
working in WP8D and ICAO to document GPS requirements and the
requirements for new systems in this band. Studies are largely completed
to determine interference requirements of a broad range of GPS receivers
covering safety and non-safety applications.

Further work is planned for the next WP8D meeting.

[PRELIMINARY VIEW]{.underline}: Based on present and future requirements
of the radionavigation satellite services and in particular civil
aviation, there is a need to retain the 1559-1610 MHz band for exclusive
use by ARNS and the RNSS. Accordingly, the United States opposes any
proposed MSS allocation in the 1559-1610 MHz band, and recommends
suppression of Res. 220. **(19Jan99)**