WORLD METEOROLOGICAL
ORGANIZATION
CBS/SG-RFC 2001/Doc. 2.2(7)
(27.II.2001)
_____________
_______
COMMISSION FOR BASIC SYSTEMS
STEERING GROUP ON RADIO FREQUENCY
COORDINATION
ITEM 2.2
GENEVA, 3-8 MAY 2001
ENGLISH only
WORKING DOCUMENT- ANALYSIS OF POSSIBLE SHARING OF THE BAND 16831690 MHZ BETWEEN METEOROLOGICAL SATELLITE (GVAR) GROUND
STATIONS AND MOBILE STATIONS OPERATING IN THE MOBILE
SATELLITE SERVICE (GSO) IN THE UNITED STATES
(Submitted By David Franc, National Weather Service)
Summary and Purpose of Document
This document, prepared by the United States has been submitted to the May 2001 meeting of ITU Working Party
7C. The document is provided to the WMO SG-RFC for information purposes.
Action Proposed
Members of the SG-RFC are invited to review and comment on the document prior to its formal presentation at
the May 2001 meeting of Working Party 7C.
INTERNATIONAL TELECOMMUNICATION UNION
RADIOCOMMUNICATION
STUDY GROUPS
Document 7C/XX-E
8D/YY-E
XX May 2001
English only
United States of America
WORKING DOCUMENT- ANALYSIS OF POSSIBLE SHARING OF THE BAND 16831690 MHZ BETWEEN METEOROLOGICAL SATELLITE (GVAR) GROUND STATIONS
AND MOBILE STATIONS OPERATING IN THE MOBILE SATELLITE SERVICE (GSO)
IN THE UNITED STATES
1.0 Introduction. Resolution 227 calls for the completion of technical studies within the ITU-R
regarding sharing between the Mobile-Satellite Service (MSS) and the Meteorological Satellite
Service (Metsat) GVAR and S-VISSR Earth Stations. The GVAR stations, deployed with ITU
Region 2, are used for user-reception of meteorological satellite processed data within the GOES
footprints. S-VISSR is a similar system deployed in ITU Region 3 and meteorological data is
received from the Japanese GMS meteorological satellite. This study investigates the feasibility of
the GSO MSS sharing spectrum within the band 1683-1690 MHz with the Government operated
Metsat GVAR receive stations within the United States. It has been determined that there a many
more non-Government GVAR stations operated within the U.S. However, identification of those
stations for inclusion in this analysis proved to difficult in the time frame available for completion
of this document.
2.0 Deployment of GVAR Stations within The United States. The GVAR signal is received by
many locations within the United States from both GOES East and GOES West. Users of the data
include the government agencies, commercial weather services, universities, research institutions,
and other government facilities. Operators of GVAR receiving stations are not required to register
their stations. As a result, identification of the non-government stations proved to be extremely
difficult and ultimately could not be accomplished. Identification of the systems operated in
support of the U.S. Government operations was accomplished for this study. The stations listed in
this document are all the stations known, to date, to be operated in support of U.S. Government
operations. Table 1 is a list of stations where sufficient data could be obtained in a timely manner
to accomplish the development of example exclusion zones. Example exclusion zones are provided
since the GSO MSS MES characteristics and deployment may be slightly different that what was
used in this study, resulting in exclusion zones that could be slightly different size. Table 2 is a list
of additional stations where sufficient data could not be obtained to accomplish a thorough analysis
of required exclusion zones. The information in these lists does not preclude the identification of
additional existing or new GVAR stations at a later time.
TABLE 1- Locations of Government Fixed GVAR Stations Operated in the
United States- Sufficient Data Available to Perform Analysis of Required
Exclusion Zones
Site or User
NWS Tropical
Prediction Center
NWS Severe Storms
Prediction Center
NWS Specialized
Center for Aviation
NWS Southern Region
Headquarters
NOAA Office of
Atmospheric
Research- CSU
CIMSS University of
Wisconsin
NWS National
Operational
Hydrologic Remote
Sensing Center
NESDIS, Suitland
NESDIS Wallops
Island CDA
National Data Buoy
Center
Goddard Space Flight
Center Site #1
Goddard Space Flight
Center Site #2
Goddard Space Flight
Center Site #3
NASA Langley
Research Center
Federal Aviation
Administration
NASA Johnson Space
Center
Latitude
25 45’ 14” N
Longitude
80 23’ 2” W
35 14’ 0.48” N
97 27’ 40.2” W
39 16’ 37.62” N
94 39’ 48.96”W
32 45’ 3.9” N
97 19’ 57.6” W
40 34’ 41.7” N
105 4’ 51.96” W
43 4’ 50.94” N
89 25’ 55.86” W
44 51’ 35.64” N
93 31’ 38.58” W
38 50’ 59.36” N
37 56’ 48” N
76 55’ 51.9” W
75 27’ 33” W
30 21’ 18” N
89 36’ 46” W
39 00’ 2” N
76 50’ 30.5” W
38 59’ 48” N
76 50’ 58.2” W
38 59’ 33.6” N
76 50’ 22.8” W
37 5’ 40” N
76 20’ 31” W
28 5’ 27.06” N
80 38’ 17.82” W
29 33’ 36” N
95 5’ 9.6” W
TABLE 2- Government Fixed GVAR Stations Operated in the
United States – Insufficient Data Available For Exclusion Zone
Analysis (1)
Location
Approximate
Latitude
38 35’ N
34 56’ N
42 29’ N
41 8’ N
35 6’ N
30 11’ N
21 20’ N
21 22’ N
36 36’ N
38 35’ N
32 23’ N
36 56’ N
41 7’ N
33 54’ N
30 29’ N
Approximate
Longitude
89 54’ W
117 56’ W
71 16’ W
95 53’ W
79 14’ W
89 36’ W
157 56’ W
158 W
121 53’W
121 30’ W
106 28’ W
76 18’ W
111 58’ W
117 16’ W
86 32’ W
Scott AFB, O’Fallon, IL
Edwards AFB, Edwards, CA
Hanscom AFB, Bedford, MA
Offutt AFB, Bellevue, NE
Ft. Bragg, Fayetteville, NC
Stennis AFB, MS
Hickam AFB, Oahu, HI
Pearl Harbor, Oahu, HI
Navy FNMOC, Monterey, CA
McClellan, AFB, Sacramento, CA
White Sands Missile Range, NM
Norfolk Navy Base, Norfolk, VA
Hill AFB, Ogden, UT
March AFB, Riverside, CA
Eglin AFB, Okaloosa, FL
Point Magu, CA
Robins AFB, GA
32 38’ N
83 35’ W
Tinker AFB, OK
35 25’ N
97 23’ W
Peterson AFB, CO
38 49’ N
104 42’ W
Keesler AFB, Biloxi, MS
30 24’ N
88 56’ W
USAF Valley Forge, PA
40 5’ N
75 28’ W
Jacksonville, FL
30 20’ N
81 39’ W
Whidbey Island, WA
48 21’ N
122 39’ W
Roosevelt Roads, PR
Coronado NAS, San Diego, CA
32 42’ N
117 2’ W
Nellis AFB, Las Vegas, NV
36 14’ N
115 2’ W
Pensacola, FL
30 28’ N
87 12’ W
Davis-Monthan AFB, AZ
32 10’ N
110 53’ W
Anderson AFB, Guam
Elmendorf AFB, Anchorage, AK
61 15 N
149 49’ W
Notes:
(1)- Additional work is required to collect data and perform exclusion zone analysis.
TABLE 3- GOVERNMENT MOBILE AND TRANSPORTABLE GVAR STATIONS
OPERATED BY THE UNITED STATES IN ITU REGION 2
At least 50 Mobile/Transportable StationsOperated within the GOES East and GOES West
Defense and Disaster Response Operations
Footprints
3.0 Analysis.
3.1 Fixed GVAR Station Locations. Sharing between the GSO MSS and fixed GVAR stations may
be feasible if exclusion zones can be established and enforced around the GVAR receivers and the
number of GVAR receivers is relatively low. Sharing would become infeasible if the number of
GVAR stations is large so exclusion zones would prevent MSS operation in large geographic areas.
Development of example exclusion zones was performed using the propagation model in ITU-R
Recommendation P.452-8, with terrain data. In addition, site conditions such as antenna heights
were considered. ITU-R Recommendation P-452-8 is designed for analysis of interference between
systems, operated above 0.7 GHz, on the Earth’s surface. It considers all propagation mechanisms
that contribute significantly to the propagation of interfering signals, including diffraction, ducting,
and troposcatter. The model was configured for use of the Metsat long-term interference criteria
and as a result, a time percentage of 20% was used in the model. The resulting contours show the
areas where MSS operation would exceed the long-term criteria for more than 20 % of the time. In
most cases GVAR receive stations operate two antennas for reception from both GOES East and
GOES West.
3.1.1 MSS Mobile Earth Station (MES) Characteristics. Primary interest in the band 1683-1690
MHz is to satisfy the spectrum requirements of the GSO MSS. This analysis will use the
characteristics of newer generation GSO MSS systems identified in Recommendation ITU-R
M.1184-1. The characteristics used in Recommendation ITU-R SA.1158-2 are no longer valid for
future systems. The GSO MSS characteristics necessary for the analysis are summarized below in
Table 4. The antenna gains of the newer generation GSO MSS MES’s vary, but are typically lower
gain than older MES’s. An antenna gain of 4 dBi, directed towards the horizon was selected for the
analysis. The height of the MES antenna above terrain is not a value specified in M.1184-1.
Discussions with GSO MSS users within the U.S. revealed that while many MES’s are operated
while on or very near the ground, they are also operated from rooftops of buildings periodically.
Therefore, an antenna height of 20 meters was used in the analysis. The density of GSO MSS
MES’s that could be expected to operate around a metsat station is not readily available. For this
study, contours were modelled for two cases: 1) a single MES contributing interference to the
GVAR station and 2) 32 MES’s contributing to interference of the GVAR station. For the second
case, the selection of 32 MES’s was to show the effect of aggregate interference from a
significantly large number of stations. It is not intended to imply that this is the number of stations
that could contribute to the interference. The actual value could be higher or lower.
TABLE 4- GSO MSS Mobile Earth Station
Characteristics
Antenna Gain (dBi)
4
MSS MES EIRP (dBW)
16
Modulation Scheme
OQPSK
Channel Spacing (kHz)
10
Antenna Height (m)
20
3.1.2 GVAR Earth station Characteristics. The GVAR stations are receive only and generally use a
7 meter (approximate) parabolic antenna. The sharing criteria specified in Recommendation ITU-R
SA.1161-1 is used in plotting the interference area contours. The full –145.4 dBW per 2.11 MHz is
used for the single MES contour. A value of –160.4 dBW per 2.11 MHz, 15 dB lower, is used to
plot the contour associated with 32 MES’s contributing interference. The locations of GVAR
antennas vary from ground installations to installations on the roofs of tall buildings. For the
analysis, the antenna azimuth and elevation necessary for maintaining a link with the GOES
satellite was considered. Therefore, the antennas were configured to track the GOES satellite and
antennas at higher latitudes have lower elevation angles.
TABLE 5- GVAR Earth Station Typical
Characteristics
Antenna Type
Antenna Size (m)
Modulation Scheme
Bandwidth (MHz)
Appendix 29
7
BPSK
4.22
Criteria, 1 MES (dBW/2.11
MHz)
-145.4
Criteria, per MES, 32
MES’s (dBW/2.11 MHz)
-160.4
Antenna Height (m)
Varies from ground level
to rooftop installations
3.1.3 Analysis Results. The exclusion zone size required to protect the fixed GVAR stations varied
considerably depending on the GVAR station parameters and the local terrain. Annex 1 contains
the individual plots for the required exclusion zones around each of the fixed stations identified in
Table 1. Most stations have two antennas for receiving from both GOES East and GOES West.
Only the plot for the antenna that requires the larger exclusion zone is provided in Annex 1. Figure
1 provides a mosaic of the exclusion zones, based on 1 MES’ circular contours, in the United States
that include the exclusion zone areas that are required to protect the identified fixed Government
GVAR stations. In addition, the map includes identification of those stations where insufficient data
was available to complete an exclusion zone analysis. A standard 100 km radius exclusion zone is
drawn for those stations where insufficient data was available. Circular exclusion zones are the
easiest to implement, requiring the satellite to only calculate a distance from the near-by GVAR
station(s) before allowing the MES to transmit. More complex exclusion zone shapes would reduce
the amount of area that an MES would be prohibited from operating within, but may be too
complex to be feasible. Figure 1 shows the fixed Government GVAR stations identified to date.
Identification of additional stations is possible in the future.
The analysis results indicate several trends worth noting. First, most sites where terrain shielding
was the dominant propagation limitation show that there is little difference in the required exclusion
zone for a single MES and the aggregate effect of 32 MES’s. Annex 1 Figures B, E and F are good
examples. However, there are a few exceptions where interference occurred a high point in the
terrain at a much further distance for the 32 MES case that did not occur in the 1 MES case.
Figures D and K in Annex are examples. A significant number of GVAR stations are operated
along the coast, where ducting is the dominant contributor to the interference. Figures C, I, J, N, O,
and P cases where ducting is the dominant interference contributor. In these cases, the curve for the
32 MES’s is most likely not valid since the probability is very low of many MES’s meeting the
correct geometry for ducting into the GVAR station.
The analysis contained in this study is based on some assumptions of the GSO MSS MES
characteristics and deployment. If exclusion zone implementation was considered feasible a more
thorough analysis using more applicable MES characteristics and deployment scenarios is required.
50N
45N
40N
IDENTIFIED
GVAR
STATIONINSUFFICIENT
DATA FOR
THOROUGH
EXCLUSION
ZONE
ANALYSIS
0
SCALE (km)
200
130W
IDENTIFIED
GVAR
STATIONREQUIRED
EXCLUSION
ZONE
400
120W
110W
100W
90W
80W
70W
FIGURE 1- MAP SHOWING CIRCULAR AREAS THAT ENCOMPASS THE EXCLUSION ZONES WHERE MSS OPERATIONS
WOULD BE PROHIBITED, TO PROTECT EXISTING GOVERNMENT OPERATED GVAR RECEIVING SYSTEMS (STATIONS WHERE
INSUFFICIENT DATA AVAILABLE HAVE 100 KM RADIUS EXCLUSION ZONES INDICATED. LARGER ZONES (UP TO 250 KM
RADIUS) MAY BE REQUIRED WHEN DATA IS MADE AVAILABLE FOR ANALYSIS.
35N
30N
25N
20N
3.2 Mobile/Transportable GVAR Stations. Table 3 indicates the existence of at least 50
Government operated mobile/transportable GVAR systems that are used within the GOES East and
GOES West footprints. Since these stations are mobile/transportable, coordination with the Mobile
Satellite Service is not feasible. There is no manner in which to establish exclusion zones around
these stations. Protection of the mobile/transportable stations is critical as they are used for defense
operations and response to manmade and natural disasters within ITU-Region 2. Operation of these
stations is required in countries within Region 2 other than the United States. Due to the inability of
protecting these stations, use of the band 1683-1690 MHz by the MSS is infeasible.
4.0 Conclusion. Analysis of sharing between the GSO MSS and the GVAR receive stations
operated in the meteorological satellite service indicates that the fixed U.S. Government GVAR
stations could be protected with the establishment of exclusion zones around the stations. Example
analyses are provided to indicate the magnitude of the exclusion zone sizes required. The only
stations identified in detail in this study are for Government operations. Additional nonGovernment stations, numbering in the hundreds have also been identified, but without sufficient
information to include in the analysis. If these additional stations are also included in the stations
that must be protected, MSS operations in this band would be limited in geographic area.
Furthermore, deployment of future GVAR stations will make sharing considerably more difficult
and could require operational changes to the MSS system.
The limitations placed on the MSS for protecting the fixed GVAR stations is not the limiting factor
in the feasibility of MSS use of the band 1683-1690 MHz. The mobile/transportable stations cannot
be protected with the use exclusion zones. Protection of a receive station where the location
changes periodically and is unknown is not possible. The U.S. requires the capability to use these
receive stations within the GOES (East and West) footprints for both defence operations and
humanitarian efforts. As noted in Section 3.2, operation of these mobile/transportable stations is
required within the entire GOES footprints, which encompasses more than ITU Region 2. In
conclusion, MSS use of the band 1683-1690 MHz is not feasible within ITU Region 2.
ANNEX 1PLOTS OF EXCLUSION ZONES FOR
INDIVIDUAL FIXED GVAR STATIONS
FIGURE A- Potential Interference Areas Around the NWS Severe Storms Prediction Center
(Norman, OK) GOES West GVAR Station.
FIGURE B- Potential Interference Areas Around the NWS Aviation Prediction Center
(Kansas City) GOES West GVAR Station.
FIGURE C- Potential Interference Areas Around the NWS Tropical Prediction Center
(Miami, FL) GOES West GVAR Station.
FIGURE D- Potential Interference Areas Around the NWS Southern Region Headquarters
(Ft. Worth, TX) GOES West GVAR Station.
FIGURE E- Potential Interference Areas Around NOAA Office of Atmospheric Research
(Colorado State Univ.) GOES West GVAR Station.
FIGURE F- Potential Interference Areas Around Cooperative Institute for Meteorological
Satellite Studies (CIMSS) (Univ. of Wisconsin) GOES West GVAR Station.
FIGURE G- Potential Interference Areas Around the NWS National Hydrologic Remote
Sensing Center (NOHRSC) (Chanhassen, MN) GOES West GVAR Station.
FIGURE H- Potential Interference Areas Around the NESDIS Headquarters (Suitland, MD)
GOES West GVAR Station.
FIGURE I- Potential Interference Areas Around the NESDIS CDA Station (Wallops Island,
VA) GOES East GVAR Station.
FIGURE J- Potential Interference Areas Around the National Data Buoy Center GOES West
GVAR Station.
FIGURE K- Potential Interference Areas Around the Goddard Space Flight Center GOES
West GVAR Station- Location #1.
FIGURE L- Potential Interference Areas Around the Goddard Space Flight Center GOES
West GVAR Station- Location #2.
FIGURE M- Potential Interference Areas Around the Goddard Space Flight Center GOES
West GVAR Station- Location #3.
FIGURE N- Potential Interference Areas Around the NASA Langley Research Center GOES
West GVAR Station.
FIGURE O- Potential Interference Areas Around the FAA Receive Station (Melbourne, FL)
GOES West GVAR Station.
FIGURE P- Potential Interference Areas Around the NASA Johnson Space Center GOES
West GVAR Station.