1、 Rec. ITU-R RS.1260-1 1 RECOMMENDATION ITU-R RS.1260-1*, *Feasibility of sharing between active spaceborne sensors and other services in the range 420-470 MHz (Question ITU-R 218/7) (1997-2003) The ITU Radiocommunication Assembly, considering a) that synthetic aperture radars (SARs) can measure soil
2、 moisture, forest biomass, can detect buried geologic structures such as faults, fractures, synclines and anticlines, and can map and measure the depth of Antarctic ice, and hydrogeological properties of arid and semiarid regions; b) that experimental SARs mounted on aircraft have demonstrated the p
3、otential for making these measurements; c) that these spaceborne SARs must operate at frequencies below 500 MHz in order to penetrate dense vegetation and the Earths surface on a worldwide repetitive basis; d) that the need for monitoring forests was emphasized at the United Nations Conference on En
4、vironment and Development (UNCED) in Rio de Janeiro, 1992; e) that Resolution 727 (Rev.WRC-2000) seeks provision of up to 6 MHz of frequency spectrum to the Earth exploration-satellite service (active) in the frequency range 420-470 MHz in order to meet the Earth exploration-satellite service (activ
5、e) requirements; f) that frequency bands between 420-470 MHz are currently allocated to the radiolocation, fixed, amateur, space operations and mobile services; g) that within the amateur service weak-signal operations (including Earth-Moon-Earth) are conducted centred around 432 MHz, and amateur-sa
6、tellite operations (both uplink and downlink) are conducted in the band 435-438 MHz; *NOTE The following Administrations Saudi Arabia, Djibouti, Egypt, United Arab Emirates, Jordan, Kuwait, Morocco, Mauritania, Syrian Arab Republic, Tunisia and Yemen object to the approval of this Recommendation. Fo
7、r more details, please refer to the appropriate Summary Record of RA-03. *Radiocommunication Study Group 7 made editorial amendments to this Recommendation. 2 Rec. ITU-R RS.1260-1 h) that other uses are made of portions of these bands including: wind profilers in the range 440-450 MHz, and in case o
8、f incompatibility between wind profiler radars and other applications, in the bands 420-435 MHz and 438-440 MHz (Resolution 217 (WRC-97); launch vehicle range safety command destruct receivers in the band 449.75-450.25 MHz (No. 5.286 of the Radio Regulations (RR), as well as around 421.0, 425.0, 427
9、.0, 440.0 and 445.0 MHz in the United States of America and Brazil and, in the French Overseas Departments in Region 2 and India, the band 433.75-434.25 MHz (RR No. 5.281); j) that certain spaceborne SARs could produce pfds at the Earths surface in excess of the pfd levels that may be required to pr
10、otect the fixed service and the land mobile service allocated in this frequency range; k) that co-frequency sharing with wind profilers is likely to be unfeasible due to interference to the spaceborne active sensor; l) that SARs and the amateur service (primary in Region 1 and secondary in Regions 2
11、 and 3, except as in RR No. 5.278) can coexist in the band 430-440 MHz, by taking appropriate technical and operational measures defined in Annex 1 to this Recommendation; m) that in addition, the provisions of RR Nos. 5.274, 5.275, 5.276, 5.277, 5.278, 5.281 and 5.283 list countries that have defin
12、ed portions of the band between 430 and 440 MHz as having primary status for the fixed, mobile, space operation and/or the amateur services; n) that some sharing studies have indicated that co-frequency sharing between the amateur services and some proposed SARs in the Earth exploration-satellite se
13、rvice (EESS) is possible for some amateur modes of transmission such as FM and time division multiple access (TDMA), but would be difficult with continuous wave and single sideband modes of operation; o) that Recommendation ITU-R M.1462 contains the technical and operational characteristics of, and
14、protection criteria for, radars (airborne, shipborne, and space object tracking) operating in the radiolocation service operating in the band 420-450 MHz; p) that there is a potential for unacceptable interference from some spaceborne SARs to terrestrial space object tracking radars operating in the
15、 band 420-450 MHz if the spaceborne SAR radar is within the view of the terrestrial radars (i.e. above the radars visible horizon); q) that some spaceborne SARs will be tracked by terrestrial space object tracking radars, and that the resultant unwanted received power level at a spaceborne SAR can a
16、pproach its maximum power-handling capability; Rec. ITU-R RS.1260-1 3 r) that there is a potential for unacceptable interference from some spaceborne SARs to airborne and shipborne radars operating in 420-450 MHz, the probability and severity of which is highly dependent upon the characteristics of
17、the SARs; s) that any harmful interference, even for very short periods, by SARs into launch vehicle command destruct receivers could impede the safety of life and property; t) that given the complexity of the EESS (active) instruments implementation in these low frequencies, very few such platforms
18、 are expected to be in orbit at the same time, recommends 1 that active spaceborne sensors operating in the bands used by the amateur service, the amateur satellite service, the fixed, radiolocation, space operation, mobile services and the MSS in the range 420-470 MHz, respect the technical and ope
19、rational constraints provided in Annex 1 to this Recommendation; 2 that spaceborne active sensors operating in the range 420-450 MHz not be put into operation within view of the terrestrial space object tracking radars listed in Table 2, unless detailed analysis, on a case-by-case basis, to include
20、consideration of the effects of the radars receiver processing upon unwanted SAR signals, and possibly field testing have been performed to confirm compatibility with the mutual agreement of the affected administrations; 3 that a spaceborne SAR intended for operation in the 420-450 MHz band be desig
21、ned to tolerate the unwanted signal power levels that will result from being tracked by terrestrial space object tracking radars; 4 that sufficient frequency and geographical separation between spaceborne SARs and wind profilers operating in the ranges 420-432 MHz and 438-450 MHz may need to be prov
22、ided; 5 that spaceborne active sensor frequency bands be selected in such a way as not to overlap with launch vehicle range safety command destruct receive frequency bands listed in considering h); 6 that in cases where recommends 5 becomes difficult to implement, spaceborne active sensors operating
23、 in the frequency ranges allocated for launch vehicle range safety command destruct receive frequency bands should not be put into operation within the specific distance of locations where launch vehicle commands are used, in order to avoid interference from spaceborne active sensors into launch veh
24、icle receivers. 4 Rec. ITU-R RS.1260-1 Annex 1 Technical and operational constraints for EESS (active) operating in the range 420-470 MHz For the purposes of protecting stations operating in the existing services, SAR transmissions from stations in the EESS (active) operating in the frequency range
25、420-470 MHz are subject to the technical and operational constraints specified in this Annex. The following constraints are based on ITU-R studies. Annex 2 provides information on the feasibility of sharing between active spaceborne sensors and other services in the range of 420-470 MHz. 1 Technical
26、 constraints TABLE 1 Technical constraints for EESS (active) instruments in the range 420-470 MHz 2 Operational constraints EESS (active) operating in the band 420-450 MHz shall not transmit within view of the terrestrial space object tracking radars listed in Table 2, unless detailed analysis, to i
27、nclude consideration of the effects of the radars receiver processing upon unwanted SAR signals, and possibly field testing, have been performed to confirm compatibility. As a consequence of the above constraints, EESS (active) instruments shall be designed in such a way as to allow programmable tur
28、ning off of all RF emissions over geographical areas or countries where ITU regulations or national regulations do not allow their operations. The EESS (active) instruments operation profile shall be campaign-oriented, targeted to specific geographical areas and shall limit the instrument active tim
29、e to the minimum required to achieve the campaign objectives. Thus, the measurements carried out by the instrument do not require continuous operation of the instrument, and intervals of months between successive measurements on the same area can be expected. The operational duty cycle in campaign-m
30、ode will be 15% maximum (typically 10%). While not in campaign-mode, the instrument will be switched off. Parameter Value Peak pfd on Earths surface from antenna main lobe 140 dB(W/(m2 Hz) Maximum mean pfd on Earths surface from antenna main lobe 150 dB(W/(m2 Hz) Maximum mean pfd on Earths surface f
31、rom 1st antenna side lobe 170 dB(W/(m2 Hz) Rec. ITU-R RS.1260-1 5 1260-01160 140 120 100 80 60 40 20 0 20 40 60 80 100 120 140 16002040608020406080FIGURE 1Example of exclusion zone around space object tracking radars for a SAR in a 550 km orbitTABLE 2 Space object tracking radars operating in 430-44
32、0 MHz Radar location Latitude Longitude Massachusetts (United States of America) 41.8 N 70.5 W Texas (United States of America) 31.0 N 100.6 W California (United States of America) 39.1 N 121.5 W Georgia (United States of America) 32.6 N 83.6 W Florida (United States of America) 30.6 N 86.2 W North
33、Dakota (United States of America) 48.7 N 97.9 W Alaska (United States of America) 64.3 N 149.2 W Thule (Greenland) 76.6 N 68.3 W Fylingdales Moor (United Kingdom) 54.5 N 0.4 W Pirinclik (Turkey) 37.9 N 40.0 E 6 Rec. ITU-R RS.1260-1 3 Protection criteria for existing services in the frequency range 4
34、20-470 MHz Not all protection criteria mentioned in this section are contained in ITU-R Recommendations. Therefore, some of these protection criteria have been derived from information provided in ITU-R studies. Table 3 reflects the information available at the time of the development of this Recomm
35、endation. It should be noted that any future Recommendation describing the protection criteria for any given service, has preference above the value listed in the table as derived from ITU-R studies. TABLE 3 Protection criteria for services in the range 420-470 MHz Frequency range (MHz) ITU-R servic
36、es The time percentages and criteria in columns 4 and 5 are to be applied only in the following geographical areas Maximum percentage of time that the criteria may be exceeded(1)Interference criteria at receiving stations Sources 430-440 Amateur Within line-of-sight (LoS) of terrestrial amateur stat
37、ions located in regions defined in considering l) 1% pfd = 204 dB(W/(m2 Hz)(2)ITU-R studies 435-438 Amateur satellite Within LoS of satellite amateur earth stations located in regions defined in considering l) 1% pfd = 197 dB(W/(m2 Hz)ITU-R studies 435-438 Amateur satellite Within LoS of receivers o
38、f amateur space stations 1% pfd = 187 dB(W/(m2 Hz) ITU-R studies 420-470(3)Fixed Within LoS of stations of the fixed service including stations located in regions defined in considering m) Not applicable (I/N)MEAN= 20 dB (equivalent to 1% fractional degradation in performance) Recs. ITU-R F.758 and
39、ITU-R F.1108 420-432 and 438-450 Radio-location Within LoS of wind profiler radars (4)(I/N)PEAK= 6 dB Rec. ITU-R M.1462 420-450 Space operation Within LoS of launch vehicle command destruct receivers located in regions defined in considering m) Frequency or geographical separation required ITU-R stu
40、dies Rec. ITU-R RS.1260-1 7 TABLE 3 (end) Annex 2 Methodology for interference assessment and mitigation 1 Introduction A methodology is presented that allows an estimate to be made as to whether or not the unwanted signal received by other services in the band 420-470 MHz from an active spaceborne
41、sensor may cause difficulties if operated in common frequency bands. Much of the content of this Annex has been extracted from Annex 1 of Recommendation ITU-R RS.1280 Selection of active spaceborne sensor emission characteristics to mitigate the potential for interference to terrestrial radars opera
42、ting in frequency bands 1-10 GHz. The calculations highlight a number of parameters of the sensor that can be chosen such that the sharing situation is improved. Frequency range (MHz) ITU-R services The time percentages and criteria in columns 4 and 5 are to be applied only in the following geograph
43、ical areas Maximum percentage of time that the criteria may be exceeded(1)Interference criteria at receiving stations Sources 420-450 Radio-location Within LoS of terrestrial space object tracking radars(5)(4)(I/N)PEAK = 6 dB Rec. ITU-R M.1462 420-450 Radio-location Within LoS of shipborne radars (4
44、)(I/N)PEAK= 6 dB Rec. ITU-R M.1462 420-450 Radio-location Within LoS of airborne radars (4)(I/N)PEAK= 6 dB Rec. ITU-R M.1462 420-470(3)Mobile Within LoS of mobile stations including stations located in Regions defined in considering m) 0.1% pfd = 204 dB(W/(m2 Hz)(2)ITU-R studies (1)Considering all a
45、ctive SARs in this frequency range. (2)The maximum aggregate pfd specified for the band 430-440 MHz has been based on the maximum acceptable interference level received by the average side lobe of an amateur receiving antenna. (3)In the frequency range 430-440 MHz, the fixed and mobile services are
46、allocated only in some countries by footnote. (4)The criterion given in Recommendation ITU-R M.1462 is based on the protection of radiolocation systems from noise-like interference. Sharing may be possible between radiolocation systems and spaceborne active sensors at interference levels greater tha
47、n those given in Recommendation ITU-R M.1462 through the use of signal processing techniques to filter out unwanted pulsed emissions. Recommendation ITU-R M.1372 provides a description of some of these interference suppression techniques. (5)The EESS (active) operating in the band 420-450 MHz shall
48、not transmit within view of the terrestrial space object tracking radars listed in Table 2, unless detailed analysis, on a case-by-case basis, to include consideration of the effects of the radars receiver processing upon unwanted SAR signals, and possibly field testing, have been performed to confi
49、rm compatibility with the mutual agreement of the affected administrations. 8 Rec. ITU-R RS.1260-1 2 Calculation of interference to other services The average interfering signal pfd, Ipfd(dB(W/(m2 Hz) and average interfering signal power level, I (dBW), received by the other services from spaceborne active sensors is calculated from the following: Ipfd= 10 log Pt+ 10 log ( PRF ) + Gt (130.99 + 20 log R + 10 log B) + OTR PG (1a) and I = 10 log Pt+ 10 log ( PRF ) + Gt+ Gr (32.44 + 20 log ( f R ) + OTR
