ITU-R SA 1810-1-2017 System design guidelines for Earth exploration-satellites operating in the band 8 025-8 400 MHz.pdf

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1、 Recommendation ITU-R SA.1810-1 (07/2017) System design guidelines for Earth exploration-satellites operating in the band 8 025-8 400 MHz SA Series Space applications and meteorology ii Rec. ITU-R SA.1810-1 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, effi

2、cient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector ar

3、e performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1.

4、Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can als

5、o be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mob

6、ile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum man

7、agement SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2017 ITU 2017 All rights reserved. No pa

8、rt of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R SA.1810-1 1 RECOMMENDATION ITU-R SA.1810-1 System design guidelines for Earth exploration-satellites operating in the band 8 025-8 400 MHz (Question ITU-R 139/7) (2007-2017) Scope The use

9、 of the 8 025-8 400 MHz band by Earth exploration-satellite service (EESS) satellites operated by various entities for data downlink operations is increasing and could result in harmful interference between these operators. Potential difficulties in sharing the heavily occupied 8 GHz spectrum may be

10、 avoided, if EESS satellite designers carefully select which of the mitigation methods are appropriate for the satellites intended operations. In addition to improving the sharing conditions for EESS satellites, many of the mitigation methods can also be beneficial in reducing or eliminating potenti

11、al coordination with the extremely sensitive space research service (deep space) operating in the adjacent 8 400-8 450 MHz band. This Recommendation provides guidance in the form of a list of possible mitigation methods, shown in recommends, for consideration to reduce the potential for interference

12、 by and to EESS satellites given the growing interest in the use of the 8 025-8 400 MHz band by the EESS. Keywords Earth Exploration-Satellite Service, system design Related Recommendations and Reports Recommendation ITU-R SA.1157 The ITU Radiocommunication Assembly, considering a) that Earth explor

13、ation-satellite service (EESS) satellites are an increasingly important tool for acquiring information about the Earth and its environment; b) that use of the band by EESS operated by commercial interests, governmental organizations and space agencies is increasing and could result in harmful interf

14、erence among EESS systems; c) that proper selection of orbital parameters for sun-synchronous satellites can be a very effective interference mitigation technique which in general requires coordination at an early stage of system development; d) that homogeneity among a set of technical parameters,

15、and in particular power flux-density (pfd) levels, will lead to a more efficient use of the orbit/spectrum resource by the EESS; e) that high-gain antennas on EESS satellites typically radiate power only towards a limited portion of the Earths surface but the higher obtained e.i.r.p. may be a disadv

16、antage for co-located stations; f) that isoflux antennas have a more uniform pfd distribution across the surface of the Earth as compared to omnidirectional antennas; g) that broadcast modes generally cause higher levels of interference due to continuous transmissions and relatively high power spect

17、ral densities but have typically lower bandwidth requirements; 2 Rec. ITU-R SA.1810-1 h) that more than 90% of all EESS satellites operate at pfd levels below 147dB(W/m2 4 kHz) for high angles of arrival at the surface of the Earth; i) that the interference risk is more significant in high latitude

18、areas since most of Earth exploration-satellites use polar orbits; j) that tropospheric propagation effects in high latitude areas are generally limited; k) that proper selection of bandwidth/power efficient modulation and coding techniques could result in smaller occupied bandwidths and lower adjac

19、ent channel interference; l) that higher order advanced modulation schemes, such as 16 PSK and above, need less bandwidth than currently used QPSK and 8-PSK but generally require higher pfds; m) that a number of other interference mitigation techniques such as polarization discrimination, earth stat

20、ion separation and earth station antenna discrimination may also result in lower interference levels; n) that receiving earth stations in the space research service (SRS) (deep-space), operated in the adjacent 8 400-8 450 MHz band, are extremely sensitive and potentially susceptible to interference

21、from out-of-band emissions of EESS (space-to-Earth) satellite transmissions in the 8 025-8 400 MHz band; o) that time-critical events occur in both SRS (deep-space) and EESS operations; p) that most of the mitigation techniques proposed to reduce interference between EESS data transmission links als

22、o reduce out-of-band emissions received by SRS (deep-space) stations in the adjacent 8 400-8 450 MHz band, recognizing a) that the increasing possibility of congestion in the 8 025-8 400 MHz band and requirements for higher data rates will lead to increasing levels of interference; b) that guideline

23、s for EESS (space-to-Earth) operations in the 8 025-8 400 MHz band are desirable to maximize the capacity of the band and to minimize harmful interference; c) that different mitigation methods may be required to resolve potential difficulties in the sharing of the band 8 025-8 400 MHz by different c

24、ombinations of EESS systems, recommends that the following guidelines should be considered when designing EESS systems operating in the 8 025-8 400 MHz band: 1 that EESS satellites operating in a non-broadcasting mode should radiate only when transmitting data to one or more earth stations; 2 that p

25、hasing of the orbital parameters for sun-synchronous satellites with existing and planned satellites should be considered; 3 that, whenever practicable, low side-lobe, high-gain satellite antennas should be used and if not practicable, isoflux antennas should be considered instead of omnidirectional

26、 antennas; 4 that broadcast modes should be avoided whenever practicable or, if unavoidable, the use of a portion of the lower half of the band 8 025-8 400 MHz be considered; 5 that bandwidth efficient modulation and coding techniques should be used to the extent practicable, to reduce the potential

27、 for adjacent channel interference by simultaneously limiting pfd, out-of-band emissions and occupied bandwidth; Rec. ITU-R SA.1810-1 3 6 that, to reduce the possibility of intersystem interference, due consideration should also be given to other interference mitigation techniques such as polarizati

28、on discrimination, geographical separation of earth stations and large earth station antennas with off-axis gains that do not exceed 32-25 log dBi for 1 48; 7 that EESS spacecraft using directional antennas be designed to limit the power flux-density on the Earths surface in all areas with latitudes

29、 above 55 or below 55 to less than 145 dB(W/m2) for a reference bandwidth equal to 4 kHz; 8 that EESS spacecraft using isoflux antennas be designed to limit the power flux-density on the Earths surface to less than 150 dB(W/m2) for a reference bandwidth equal to 4 kHz; 9 that EESS spacecraft not usi

30、ng directional or isoflux antennas should be designed to limit the power flux density on the Earths surface to less than 147 dB(W/m2) for a reference bandwidth equal to 4 kHz; 10 that, in order to minimize the need for operational coordination, EESS satellites should utilize appropriate techniques t

31、o prevent, to the extent possible, unwanted emissions exceeding the ITU-R space research service (deep-space) protection criterion1 in the band 8 400-8 450 MHz, including one or more of the applicable techniques given in recommends 1 through 8, on-board filtering, large geographical separation betwe

32、en EESS and space research service (deep-space) earth stations and/or low-sideband modulations; 11 that the use of the 25.5-27 GHz band by Earth exploration-satellites should be considered in particular if the techniques given in recommends 1 through 10 cannot adequately resolve potential spectrum-sharing and/or unwanted emission issues. 1 See relevant SA-series of ITU-R Recommendations.