1、 Rec. ITU-R RS.1281 1 RECOMMENDATION ITU-R RS.1281*, *PROTECTION OF STATIONS IN THE RADIOLOCATION SERVICE FROM EMISSIONS FROM ACTIVE SPACEBORNE SENSORS IN THE BAND 13.4-13.75 GHz (Questions ITU-R 213/7 and ITU-R 204/8) (1997) Rec. ITU-R RS.1281 The ITU Radiocommunication Assembly, considering a) tha
2、t Resolution 712 (Rev.WRC-95) of the World Radiocommunication Conference (Geneva, 1995) calls for studies of the compatibility of the use of existing allocations for space-based active sensors operating in the Earth exploration-satellite and space research services in frequency bands shared with the
3、 radiolocation or radionavigation services, between 1 and 25 GHz, with a view to the possibility of establishing common worldwide primary allocations; b) that the band 13.4-14.0 GHz is allocated to the radiolocation service on a primary basis, with additional allocations to the radionavigation servi
4、ce in several countries on a primary basis; c) that currently the band 13.4-14.0 GHz is allocated for spaceborne radiolocation stations (active spaceborne sensors) on a secondary basis; d) that these studies have shown that existing and planned terrestrial radars and active spaceborne sensors in the
5、 13.4-13.75 GHz band are operationally compatible; e) that to insure future operational compatibility, restrictions need to be placed on spaceborne active sensor emissions; f) that performance degradations that spaceborne sensors could cause to terrestrial radars are of two major types: desensitizat
6、ion of detection and tracking of valid targets; the introduction of false-target effects; g) that terrestrial-radar desensitization is acceptable if its frequency of occurrence is sufficiently low and does not compromise the radars mission requirements; h) that analyses have shown that desensitizati
7、on induced by representative spaceborne sensors is acceptably infrequent; j) that constraints on spaceborne-sensor designs are not required to prevent unacceptable desensitization; k) that the nature of radar missions in this band makes certain false-target responses unacceptable even if they were t
8、o occur quite rarely; l) that tests have resulted in interference exposure limits that protect the radar systems against unacceptable false-target responses; m) that avoidance of unacceptable false-target responses requires that these exposure limits be imposed without regard to their frequency of o
9、ccurrence; n) that expression of these limits in terms of W/(m2 MHz) could expose wideband radar receiver front ends to excessive interference powers, while expression in terms of W/m2without regard to emission bandwidth can provide the needed protection, _ *This Recommendation was jointly developed
10、 by Radiocommunication Study Groups 7 and 8, and future revisions should be undertaken jointly. *Radiocommunication Study Group 7 made editorial amendments to this Recommendation. 2 Rec. ITU-R RS.1281 recommends 1 that the power density produced at any given point on the Earths surface by emissions
11、from spaceborne active sensors operating in the Earth exploration-satellite and space research services in the band 13.4-13.75 GHz for all methods of modulation should not exceed: 71 dB(W/m2) for 0 6 71 + ( 6)/3 dB(W/m2) for 6 0.4 s (fails recommends 2.2)C: look-away time 0.1 sFIGURE 41281-04 = xx cm
