United States of America

DRAFT PROPOSAL FOR THE WORK OF THE CONFERENCE

Agenda item 1.38: to consider provision of up to 6 MHz of frequency
spectrum to the Earth exploration-satellite service (active) in the
frequency band 420-470 MHz, in accordance with Resolution 727
(Rev.WRC-2000);

**Background Information**: A similar agenda item was debated at WRC-97
resulting in a decision not to adopt proposed allocations for EESS
(active) in the band 420-470 MHz. The need for forest monitoring was
emphasized at the United Nations Conference on Economic Development
(UNCED) (Buenos Aires - 1992). Since that Conference, Recommendation
ITU-R SA.577 established requirements for the operation of spaceborne
synthetic aperture radars (SAR) at a frequency near 400 MHz to measure
soil moisture, tropical biomass, Antarctic ice thickness, and for
documentation of geological history and climate change. Studies
performed by the EESS community have identified a minimum bandwidth
requirement of up to 6 MHz to satisfy mission objectives.

As a result of studies prior to WRC-97, consideration of the potential
use of the band 410-470 MHz by active spaceborne sensors was limited to
430-440 MHz due to sharing considerations with other services. Studies
since WRC-97 have examined the range 420-470 MHz, and the conclusions
regarding sharing with other services have been updated accordingly. A
number of studies were conducted by various administrations leading to a
draft revision of Draft Revised Recommendation ITU-R SA.1260, sharing
criteria between active spaceborne sensors and other services in the
range 420-470 MHz.

**Sharing with the amateur and amateur-satellite services**

In the band 430-440 MHz, amateur services have allocations on a
co-primary basis in Region 1 and on a secondary basis in Regions 2 and 3
(except in countries listed in No. **5.278**, where it is primary).
Further, in accordance with No. **5.282** the amateur-satellite service
may operate in part of this band (435-438 MHz) subject to not causing
harmful interference to other services operating in accordance with the
Radio Regulations.

Studies leading to the draft revision of Recommendation ITU-R SA.1260
determined that there would likely be periods where SAR transmissions
would have some impact on reception by amateur services. One study
indicates that there may be the potential for significant interference
during periods of visibility of some high power SAR satellites to
amateur and amateur-satellite services. Another study of a low power,
low sidelobe SAR indicates that for a low sensitivity, low-resolution
mode the average pfd could be lower than acceptable pfd levels in the
amateur services.

It appears that the SARs and the amateur services could coexist if, and
only if, the technical and operational constraints given in Draft
Revised Recommendation ITU-R SA.1260 are met by EESS (active). Until the
characteristics of EESS SARs are more clearly defined, the amateur
community remains concerned about the potential for interference to
amateur operations in the band 430-440 MHz and especially in the portion
of the band 435-438 MHz.

**Sharing with radiolocation service**

Airborne, shipborne, and land-based radars operate in the frequency band
420-450 MHz. Studies prior to WRC-97 concentrated on the very large
aperture antenna radar systems used for space object tracking in the
band 420-450 MHz. Studies since WRC-97 have included consideration of
the compatibility of spaceborne SARs with the other types of radars
operating in the band 420‑450 MHz.

The ITU-R has determined that there is a potential for unacceptable
interference from spaceborne SARs to a limited number (around ten
worldwide) of terrestrial space object tracking radars operating in the
frequency band 420‑450 MHz if a SAR is within line-of-sight of these
radars. It has been determined that the degree of compatibility is
highly dependent upon the characteristics (and associated mission) of
the spaceborne SARs, and that a spaceborne SAR intended for certain
missions can be designed such that the compatibility situation is
considerably improved. Field-testing would be required on a
case-by-case-basis to confirm compatibility with specific systems.

The ITU-R has concluded that, taking into account the SAR processing
gain; the interference to SARs caused by terrestrial radars is
acceptable.

Operation by geographical separation (that is, spaceborne SAR operation
beyond line-of-sight to the terrestrial radars) has been studied.
Observation of significant portions of the landmass in the northern
hemisphere will be denied to the spaceborne sensors under such a
restriction. However, it does appear that if the SARs are limited to
operations beyond line-of-sight of terrestrial radars an appreciable
portion of the tropical forests or Antarctic ice sheets can still be
observed, which are primary missions for active sensors at these
frequencies.

Studies of the compatibility of spaceborne SARs with airborne and
shipborne terrestrial radars have produced results that are quite
similar to those for the land-based radars: a potential for significant
interference (i.e. with regard to the likelihood and duration of
interference events) exists for some of the SARs studied, but that the
potential is highly dependent upon the characteristics of the SARs
(orbits, transmitter power, antenna sidelobe characteristics). SAR
design and operation in compliance with Recommendation ITU-R SA.1260
would greatly improve compatibility.

In addition to the terrestrial radars that operate in the 420-450 MHz
band as addressed in the preceding paragraphs, a radar is located in
Arecibo, Puerto Rico (United States) that is used for important
atmospheric research programmes. It is an upward looking radar and there
is a potential for interference from a spaceborne SAR. Wind profiler
radars operate in the radiolocation service in the range 440-450 MHz
unless compatibility cannot be achieved with existing services, in which
case the bands 420-435 MHz and 438-440 MHz could be considered for use
by wind profiler radars in accordance with Resolution **217 (WRC‑97)**.
Operation in separate frequency bands may be necessary for spaceborne
SARs and wind profiler radars in order to preclude interference to the
SARs.

**Sharing with fixed and mobile services**

The frequency ranges 410-430 MHz and 440-470 MHz are allocated to the
fixed and mobile services on a primary basis in all three Regions. The
frequency range 430-440 MHz is allocated to the fixed service in over 40
countries on a primary basis, by footnotes to the Radio Regulations.

Draft new Recommendation ITU-R F. \[Document 9/47\] gives channel
arrangements for digital radio systems operating in the frequency range
406.1-450 MHz. General guidance on the performance characteristics of FS
systems in the band 420-470 MHz are available in Recommendation ITU-R
\[F.758 (9/131)\].

The fixed service protection criteria to be applied is a Fractional
Degradation of Performance (FDP) of 10% (which is equivalent to I/N =
−10 dB in case of permanent interference) from a primary service, and 1%
FDP (equivalent to I/N = −20 dB in case of permanent interference) from
a secondary service. The pfd derived from this criterion should not be
exceeded. Recommendation ITU-R F.758 provides the receiver thermal noise
as −143 dBW in a 3.5 MHz IF bandwidth.

A design of some low power, low-side lobe, spaceborne SARs has been
considered that may produce power flux-densities at the surface of the
Earth lower than the levels imposed in frequency bands near 400 MHz
allocated to the fixed and mobile services in order to protect fixed and
mobile operations.

In the range 450-470 MHz, interference to land mobile receivers used for
critical purposes is unacceptable if any interruption occurs, even for a
brief period of time, as the interference could impact protection of
life and property. It is essential that the pfd of any interference to
the land mobile service from EESS be less than the level specified in
Table 1 of the annex to the Draft Revised Recommendation ITU-R SA.1260.

The maritime mobile service may use some frequencies within the band
457-467 MHz for on-board communications stations (No. **5.287**).
Receiver characteristics are similar to those of land mobile equipment
listed in Recommendation ITU-R M.1174-1.

**Sharing with Space operation service (range safety command
receivers)**

Range safety command receivers are used to send arm, destruct, and safe
commands to an airborne missile or drone, as well as to launch vehicles.
Terrestrial missile and drone operations are accomplished at all flight
altitudes (from just above ground level up to maximum flight altitudes).
Commands to space launch vehicles may need to be sent from nearly ground
level (just after lift‑off) up or approaching early parking orbit
altitudes of 100 km or so (e.g. to send a final \"safe\" command).

Studies conducted within the ITU-R have demonstrated the potential for
interference from spaceborne SARs operating in the EESS into launch
vehicle range safety command receivers. Considering the safety
implications of interference into range safety command receivers from
SARs operating in the EESS, co-frequency sharing is not feasible during
a launch window. Launch vehicle range safety command destruct receivers
operate in the band 449.75-450.25 MHz (No. **5.286**), as well as at
420-430 MHz and 440-445 MHz with a 600 kHz bandwidth in the United
States, and,* *in the band 433.75-434.25 MHz in India on a primary basis
and certain countries in Region 2 on a secondary basis (No. **5.281**).

**PROPOSAL**:

**USA/ /1 [NOC]{.underline}**

ARTICLE 5

Frequency allocations

+----------------------+----------------------+-----------------------+
| 410 - 470 MHz        |                      |                       |
+----------------------+----------------------+-----------------------+
| Allocation to        |                      |                       |
| services             |                      |                       |
+----------------------+----------------------+-----------------------+
| Region 1             | Region 2             | Region 3              |
+----------------------+----------------------+-----------------------+
| **420-430** FIXED    |                      |                       |
|                      |                      |                       |
| MOBILE except        |                      |                       |
| aeronautical mobile  |                      |                       |
|                      |                      |                       |
| Radiolocation        |                      |                       |
|                      |                      |                       |
| 5.269 5.270 5.271    |                      |                       |
+----------------------+----------------------+-----------------------+
| **430-440**          | **430-440**          |                       |
|                      |                      |                       |
| AMATEUR              | RADIOLOCATION        |                       |
|                      |                      |                       |
| RADIOLOCATION        | Amateur              |                       |
+----------------------+----------------------+-----------------------+
| 5.138 5.271 5.272    | 5.271 5.276 5.277    |                       |
| 5.273\               | 5.278 5.279 5.281    |                       |
| 5.274 5.275 5.276    | 5.282                |                       |
| 5.277\               |                      |                       |
| 5.280 5.281 5.282    |                      |                       |
| 5.283                |                      |                       |
+----------------------+----------------------+-----------------------+
| **440-450** FIXED    |                      |                       |
|                      |                      |                       |
| MOBILE except        |                      |                       |
| aeronautical mobile  |                      |                       |
|                      |                      |                       |
| Radiolocation        |                      |                       |
|                      |                      |                       |
| 5.269 5.270 5.271    |                      |                       |
| 5.284 5.285 5.286    |                      |                       |
+----------------------+----------------------+-----------------------+
| **450-455** FIXED    |                      |                       |
|                      |                      |                       |
| MOBILE               |                      |                       |
|                      |                      |                       |
| 5.209 5.271 5.286    |                      |                       |
| 5.286A 5.286B 5.286C |                      |                       |
| 5.286D 5.286E        |                      |                       |
+----------------------+----------------------+-----------------------+
| **455-456**          | **455-456**          | **455-456**           |
|                      |                      |                       |
| FIXED                | FIXED                | FIXED                 |
|                      |                      |                       |
| MOBILE               | MOBILE               | MOBILE                |
|                      |                      |                       |
|                      | MOBILE-SATELLITE\    |                       |
|                      | (Earth-to-space)     |                       |
|                      | 5.286A 5.286B 5.286C |                       |
+----------------------+----------------------+-----------------------+
| 5.209 5.271 5.286A   | 5.209                | 5.209 5.271 5.286A    |
| 5.286B\              |                      | 5.286B 5.286C 5.286E  |
| 5.286C 5.286E        |                      |                       |
+----------------------+----------------------+-----------------------+
| **456-459** FIXED    |                      |                       |
|                      |                      |                       |
| MOBILE               |                      |                       |
|                      |                      |                       |
| 5.271 5.287 5.288    |                      |                       |
+----------------------+----------------------+-----------------------+
| **459-460**          | **459-460**          | **459-460**           |
|                      |                      |                       |
| FIXED                | FIXED                | FIXED                 |
|                      |                      |                       |
| MOBILE               | MOBILE               | MOBILE                |
|                      |                      |                       |
|                      | MOBILE-SATELLITE\    |                       |
|                      | (Earth-to-space)     |                       |
|                      | 5.286A 5.286B 5.286C |                       |
+----------------------+----------------------+-----------------------+
| 5.209 5.271 5.286A   | 5.209                | 5.209 5.271 5.286A    |
| 5.286B 5.286C 5.286E |                      | 5.286B 5.286C 5.286E  |
+----------------------+----------------------+-----------------------+
| **460-470** FIXED    |                      |                       |
|                      |                      |                       |
| MOBILE               |                      |                       |
|                      |                      |                       |
| Mete                 |                      |                       |
| orological-Satellite |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| 5.287 5.288 5.289    |                      |                       |
| 5.290                |                      |                       |
+----------------------+----------------------+-----------------------+

**Reasons:** ITU-R studies have not shown compatibility between EESS and
radiolocation, nor between EESS and the amateur service in the bands.

**USA/ /2 SUP**

**Resolution 727 (Rev.WRC-2000)**

**Reasons:** Consequential, Resolution **727** is no longer required.