February 26, 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
preliminary view documents.

The first preliminary view drafted by the FCC addresses the use of High
Frequency (HF) bands by the aeronautical mobile (R) and maritime
service. Our changes are shown with strikeout and underline markings.

The second preliminary view is concerned with the identification of
frequencies to support the Radionavigation-Satellite Service (RNSS).
Recently two additional frequencies were selected to support RNSS
systems. This revised preliminary view now includes the new candidate
frequencies along with a brief explanation of their intended use.

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

Enclosures

**United States Preliminary View**

**WRC-2000 AGENDA ITEM 1.7:** *review of the use of the HF bands by the
aeronautical mobile (R) and maritime mobile services with a view to
protecting operational, distress and safety communications, taking into
account Resolution* ***346 (WRC-97)**;*

[ISSUE:]{.underline} Use of High Frequency (HF) Bands by Aeronautical
Mobile (R) and Maritime Service

[BACKGROUND:]{.underline} The HF bands allocated for the distress and
safety communications of the maritime and aeronautical mobile (R)
services have been subjected to harmful interference caused by
unauthorized use. This unauthorized use of safety related HF frequencies
has increased in recent years and is resulting in considerable worldwide
interference to the operational distress and safety communications
spectrum utilized by the maritime and aeronautical communities. Radio is
the sole means of communications for the aeronautical and maritime
mobile services and the frequencies in the bands allocated to these
services are reserved or used for distress and safety purposes and that
the aeronautical mobile (R) service is a safety service. It is essential
for the safety of life and property that distress and safety channels of
the maritime mobile service and the allocations to the aeronautical
mobile (R) service be kept free from unauthorized use and harmful
interference.

The protection of maritime HF distress and safety frequencies, in
particular the frequencies 12,290 kHz and 16, 420 kHz, is addressed in
Resolution **346 (WRC-97)**. The problem of interference to distress
traffic on these frequencies is due to their use as calling frequencies.
Resolution **346** calls for administrations to minimize the use of
these frequencies for non-safety calling purposes by coast and ship
stations.

The interference to HF frequencies allocated to the aeronautical mobile
(R) service between 2850 kHz and 22,000 kHz appears to be the result of
unauthorized non-aviation use of aeronautical mobile (R) frequencies. In
some parts of the world the aeronautical mobile (R) HF frequencies are
being used for land mobile, broadcast, fixed point to point
communications and unlicensed applications to support fishing fleets.
These unauthorized applications have diminished the spectrum available
for the aeronautical mobile (R) safety of life applications.

**U.S. PRELIMINARY VIEW:** The United States will work to ensure these
safety services are protected. Administrations should ensure that
stations of services other than the aeronautical mobile (R) and maritime
mobile service abstain from using frequencies in the distress and safety
channels and their guard bands and in the bands allocated exclusively to
either the aeronautical mobile (R) or the maritime mobile service. That
Administrations make every effort to identify and located the source of
any unauthorized emission capable of endangering human life and property
and the safe and regular conduct of aircraft operations, and to take
necessary measures to prevent stations from operating in contravention
of ITU radio regulations.

**United States Preliminary View for WRC-2000**

**WRC-2000 Agenda Item 1.15.1**: *to consider new allocations to the
radionavigation- satellite service in the range from 1 to 6 GHz required
to support developments;*

**ISSUE**: Identification of a new civil frequency for RNSS

**BACKGROUND**: Additional Radionavigation-Satellite Service (RNSS)
signals will greatly enhance the accuracy, reliability and robustness of
the civil Global Positioning System (GPS) by enabling more effective
corrections to be made for the time delay effects of the ionosphere on
the signals from space. GPS currently provides signals that are used for
radionavigation on two frequencies, one of which is available for civil
applications. Additional civil signals, that are widely separated in
frequency, will allow receivers to measure the time of arrival for two
signals that have passed through the ionosphere and correct for the
delay introduced by passage from space to earth. This will result in
improved accuracy in the navigation solution. Improved location accuracy
allows safety-critical users requiring dynamic, reliable capability to
use RNSS; improves the overall accuracy of the system for the average
user; and allows high-accuracy users (aeronautical, surveying, geodesy,
weather forecasters, and others) to determine their data in a faster,
more reliable manner. In addition, the protected civil signal will
provide increased signal robustness that will help protect
safety-critical users from the effects of radio frequency interference.
The International Civil Aviation Organization (ICAO) has stated the
requirement for an additional civil signal on GPS to support Global
Navigation Satellite System (GNSS) requirements and for space-based
augmentation systems. A requirement for aeronautical users is having the
protected signal operate within radio spectrum allocated to the
Aeronautical Radionavigation Service (ARNS), which would also include
the possibility of terrestrial augmentation systems.

The United States has identified a second new civil signal at 1227.6 MHz
and a third signal at 1176.45 MHz to support GNSS developments. The
third signal is proposed to be an international civil aviation
safety-of-life service signal with a required bandwidth on the order of
24 MHz. The U.S. will be working in the ITU-R and ICAO on the
requirements and characteristics of these signals. Technical studies
tentatively show compatibility between existing operational ARNS systems
and the proposed GPS signal at 1176.45 MHz.

**PRELIMINARY VIEW**: The United States plans to seek a new RNSS
frequency allocation on a worldwide basis within the 960-1215 MHz
Aeronautical Radionavigation Service band. This allocation would be used
in conjunction with the ARNS/RNSS allocation at 1559-1610 MHz for
aeronautical safety services as well as other applications.

*This is a copy of the current preliminary view with the strikeout and
underline markings shown.*

**United States Preliminary View for WRC-2000**

**WRC-2000 Agenda Item 1.15.1**: *to consider new allocations to the
radionavigation-satellite service in the range from 1 to 6 GHz required
to support developments;* [ISSUE]{.underline}: Identification of a new
civil frequency for RNSS

[BACKGROUND]{.underline}: Additional Radionavigation-Satellite Service
(RNSS) signals will greatly enhance the accuracy, reliability and
robustness of civil Global Positioning System (GPS) by enabling more
effective corrections to be made for the time delay effects of the
ionosphere on the signals from space. GPS currently provides signals
that are used for radionavigation on two frequencies, one of which is
available for civil applications. Additional civil signals that are
widely separated in frequency, will allow receivers to measure the time
of arrival for two signals that have passed through the ionosphere and
correct for the delay introduced by passage from space to earth. This
will result in improved accuracy in the navigation solution. Improved
location accuracy allows safety-critical users requiring dynamic,
reliable capability to use RNSS; improves the overall accuracy of the
system for the average user; and allows the high-accuracy users
(aeronautical, surveying, geodesy, weather forecasters, and others) to
determine their data in a faster, more reliable manner. In addition, the
protected civil signal will provide increased signal robustness that
will help protect safety-critical users from the effects of radio
frequency interference.. The International Civil Aviation Organization
(ICAO) has stated the requirement for an additional civil signal on GPS
to support Global Navigation Satellite System (GNSS) requirements and
for space-based augmentation systems. A requirement for aeronautical
users is having the protected signal operate within radio spectrum
allocated to the Aeronautical Radionavigation Service (ARNS), which
would also include the possibility of terrestrial augmentation systems.

The United States has identified a second new civil signal at 1227.6 MHz
and a third signal at 1176.45 MHz to support GNSS developments. The
third signal is proposed to be an civil aviation safety-of-life service
signal with a required bandwidth on the order of 24 MHz. The U.S. will
be working in the ITU-R and ICAO on the requirements and characteristics
of these signals. Technical studies tentatively show compatibility
between existing operational ARNS systems and the proposed GPS signal at
1176.45 MHz. [PRELIMINARY VIEW]{.underline}: The United States plans to
seek a new RNSS frequency allocation on a worldwide basis within the
960-1215 MHz Aeronautical Radionavigation Service band. This allocation
would be used in conjunction with the ARNS/RNSS allocation at 1559-1610
MHz for aeronautical safety services as well as other applications.
**(22February99)**