1、 Recommendation ITU-R RS.2105-0 (07/2017) Typical technical and operational characteristics of Earth exploration-satellite service (active) systems using allocations between 432 MHz and 238 GHz RS Series Remote sensing systems ii Rec. ITU-R RS.2105-0 Foreword The role of the Radiocommunication Secto
2、r is to ensure the rational, equitable, efficient 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 f
3、unctions of the Radiocommunication Sector are 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 r
4、eferenced in Annex 1 of Resolution ITU-R 1. 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 t
5、he ITU-R patent information database can also 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 Broadcastin
6、g service (television) F Fixed service M Mobile, 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-satelli
7、te and fixed service systems SM Spectrum management 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 Gene
8、va, 2017 ITU 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R RS.2105-0 1 RECOMMENDATION ITU-R RS.2105-0 Typical technical and operational characteristics of Earth exploration-satellite service (active) sy
9、stems using allocations between 432 MHz and 238 GHz (2017) Scope This Recommendation provides technical and operational characteristics of Earth exploration-satellite service (active) systems using allocations between 432 MHz and 238 GHz for utilisation in sharing and compatibility studies. Keywords
10、 EESS (active), Earth exploration-satellite service, remote sensing, synthetic aperture radar, altimeters, precipitation radar, scatterometers, cloud profile radar The ITU Radiocommunication Assembly, considering a) that Earth exploration-satellite service (EESS) (active) observations may receive em
11、issions from active services; b) that EESS (active) is co-allocated with active services in certain bands; c) that studies considering protection for and from EESS (active) systems are taking place within ITU-R; d) that in order to perform compatibility and sharing studies with EESS (active) systems
12、, the technical and operational characteristics of those systems must be known, recognizing a) that Recommendation ITU-R RS.577 provides information on the bandwidths of active sensor systems envisaged to operate in the allocated bands between 432 MHz and 238 GHz; b) that several ITU-R Recommendatio
13、ns and Reports provide information on the current and future characteristics of EESS (active) systems operating in several frequency bands (see Annex, Table 2), recommends that the technical and operational parameters presented in the Annex of this Recommendation should be taken into account in stud
14、ies considering EESS (active) systems using allocations between 432 MHz and 238 GHz. 2 Rec. ITU-R RS.2105-0 Annex Technical and operational parameters of EESS (active) systems using allocations between 432 MHz and 238 GHz 1 Introduction Active sensors are used in the remote sensing of the Earth and
15、its atmosphere by Earth exploration and meteorological satellites in certain frequency bands allocated to the Earth exploration-satellite service (EESS) (active). The products of these active sensor operations are used extensively in meteorology, climatology, and other disciplines for operational an
16、d scientific purposes. The technical and operational parameters presented in this Recommendation shall be used in studies considering EESS (active) systems using allocations between 432 MHz and 238 GHz. However, it should be noted that some of the EESS (active) systems are under development and the
17、typical values for certain parameters provided should be considered preliminary as these still may change. 2 Active sensor types and typical characteristics There are five active spaceborne sensor types addressed in this Recommendation: Type 1: Synthetic aperture radars (SAR) Sensors looking to one
18、side of the nadir track, collecting a phase and time history of the coherent radar echo from which a radar image of the Earths surface from the returned echo or topography from interferometric returns can be produced. Type 2: Altimeters Sensors looking at nadir, measuring the precise time between a
19、transmit event and receive event, to extract the precise altitude of the Earths ocean surface. Type 3: Scatterometers Sensors pointing at various look angles relative to the sides of the nadir track, using the measurement of the return echo power variation with aspect angle to determine the roughnes
20、s of land surface or to determine the wind direction and speed on the Earths ocean surface. Type 4: Precipitation radars Sensors scanning perpendicular to nadir track which measure the radar echo from rainfall in order to determine the rainfall rate over the Earths surface and the three-dimensional
21、structure of rainfall. Type 5: Cloud profile radars Sensors looking at nadir which measure the radar echo return from clouds in order to determine the cloud reflectivity profile over the Earths surface. Some typical characteristics of spaceborne active sensors are shown below in Table 1. The actual
22、characteristic values of the systems operating in the various frequency bands provided in 7 of this Recommendation may vary considerably from these typical characteristic values reflected in Table 1. Rec. ITU-R RS.2105-0 3 TABLE 1 Typical characteristics of active spaceborne sensors Characteristic S
23、ensor type SAR Altimeter Scatterometer Precipitation radars Cloud profile radars Service area Land/coastal/ ocean Ocean/ice/coastal/ Inland water Ocean/ice/land/coastal Land/ocean Land/ocean Antenna beam Fan beam Pencil beam Fan beams Pencil beams Pencil beam Pencil beam Viewing geometry Side-lookin
24、g at 10-55 off nadir Nadir-looking Multi incidence looking Three/six fan beams in azimuth One or more conically scanning beams Scanning across-track around Nadir Nadir-looking Footprint/dynamics Fixed to one side ScanSAR Spotlight Fixed at nadir Multi incidence looking Fixed in azimuth Multiple coni
25、cally scanning beams Scanning across nadir track Fixed at nadir RF Bandwidth 20- 1 200 MHz 320-500 MHz 5-80 kHz (ocean) or 1-4 MHz (land) 14 MHz 300 kHz Transmit peak power (W) 1 500-7 600 20 100-5 000 600 1 000-1 500 Waveform Linear FM pulses Linear FM pulses Interrupted CW or short pulses (ocean)
26、or linear FM pulses (land) Short pulses Short pulses Transmit duty cycle (%) 1-30 46 31 (ocean) or 10 (land) 0.9 1-14 3 Typical orbits EESS (active) systems operate in non-geostationary satellite orbit (non-GSO). Orbits are typically circular with an altitude between 350 and 1 400 km. Some EESS (act
27、ive) systems operate in a sun-synchronous orbit. Some sensors make measurements over the same area on the Earth every day, while others will repeat observations only after a longer (often more than two weeks) repeat period. In certain circumstances, multiple satellites operate in formation. Formatio
28、n flying EESS satellites allow the capability to measure different Earth system characteristics (land, ocean, atmosphere, cryosphere and solid Earth) using both multiple instruments and orientations. Measurements from multiple spacecraft will be separated within an amount of time shorter than the ti
29、me constant of the phenomena being measured. Nominally, this separation is on the order of 5 to 15 min, but can be as little as a few seconds. 4 Active sensors interference and performance criteria The criteria for performance, interference and data availability are provided in Recommendation ITU-R
30、RS.1166 for the various types of active spaceborne sensors. Performance criteria for active spaceborne sensors are needed in order to develop interference criteria. Interference criteria, in turn, can be used to assess the compatibility of other active services and active sensors operating in common
31、 frequency bands. 4 Rec. ITU-R RS.2105-0 5 Sharing considerations for active sensors 5.1 Existing ITU-R Recommendations and Reports The sharing considerations for sharing between spaceborne active sensors in the EESS (active) and other services are provided in the ITU-R Recommendations and Reports l
32、isted in Table 2. These Recommendations and Reports are concerned with specific frequency bands or ranges of frequencies and the other services operating in those bands. The sharing considerations for spaceborne active sensors include the level of the power flux-density (pfd) and received interferen
33、ce power at the Earths surface, the type of transmitted RF signal, the dynamics of the antenna coupling with systems of other services, and the types of systems in the other services. TABLE 2 List of ITU-R Recommendations with sharing considerations for active sensors ITU-R RS.1260 Feasibility of sh
34、aring between active spaceborne sensors and other services in the range 420-470 MHz ITU-R RS.1261 Feasibility of sharing between spaceborne cloud radars and other services in the range of 92-95 GHz ITU-R RS.1280 Selection of active spaceborne sensor emission characteristics to mitigate the potential
35、 for interference to terrestrial radars operating in frequency bands 1-10 GHz 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 ITU-R RS.1282 Feasibility of sharing between wind profiler radars and active spaceb
36、orne sensors in the vicinity of 1 260 MHz ITU-R RS.1347 Feasibility of sharing between radionavigation-satellite service receivers and the Earth exploration-satellite (active) and space research (active) services in the 1 215-1 260 MHz band ITU-R RS.1628 Feasibility of sharing in the band 35.5-36 GH
37、z between the Earth exploration-satellite service (active) and space research service (active), and other services allocated in this band ITU-R RS.1632 Sharing in the band 5 250-5 350 MHz between the Earth exploration-satellite service (active) and wireless access systems (including radio local area
38、 networks) in the mobile service ITU-R RS.1749 Mitigation technique to facilitate the use of the 1 215-1 300 MHz band by the Earth exploration-satellite service (active) and the space research service (active) ITU-R RS.2043 Characteristics of synthetic aperture radars operating in the Earth explorat
39、ion-satellite service (active) around 9 600 MHz ITU-R RS.2065 Protection of space research service (SRS) space-to-earth links in the 8 400-8 450 MHz and 8 450-8 500 MHz bands from unwanted emissions of synthetic aperture radars operating in the earth exploration-satellite service (active) around 9 6
40、00 MHz ITU-R RS.2066 Protection of the radio astronomy service in the frequency band 10.6-10.7 GHz from unwanted emissions of synthetic aperture radars operating in the Earth exploration-satellite service (active) around 9 600 MHz Rec. ITU-R RS.2105-0 5 TABLE 2 (end) List of ITU-R Reports with shari
41、ng considerations for active sensors ITU-R RS.2068 Current and future use of the band near 13.5 GHz by spaceborne active sensors ITU-R RS.2094 Studies related to the compatibility between Earth exploration-satellite service (active) and the radiodetermination service in the 9 300-9 500 MHz and 9 800
42、-10 000 MHz bands and between Earth exploration-satellite service (active) and the fixed service in the 9 800-10 000 MHz band ITU-R RS.2178 The essential role and global importance of radio spectrum use for Earth observations and for related applications ITU-R RS.2273 Potential interference from EES
43、S (active) scatterometers into ARNS systems in the frequency band 1 215-1 300 MHz ITU-R RS.2274 Spectrum requirements for spaceborne synthetic aperture radar applications planned in an extended allocation to the Earth exploration-satellite service around 9 600 MHz ITU-R RS.2310 Worst-case interferen
44、ce levels from mainlobe-to-mainlobe antenna coupling of systems operating in the radiolocation service into active sensor receivers operating in the Earth exploration-satellite service (active) in the 35.5-36.0 GHz band ITU-R RS.2311 Pulsed radio frequency signal impact measurements and possible mit
45、igation techniques between Earth exploration-satellite service (active) systems and RNSS systems and networks in the band 1 215-1 300 MHz ITU-R RS.2313 Sharing analyses of wideband Earth exploration-satellite service (active) transmissions with stations in the radio determination service operating i
46、n the frequency bands 8 700-9 300 MHz and 9 900-10 500 MHz ITU-R RS.2314 Sharing analyses of wideband EESS SAR transmissions with stations in the fixed, mobile, amateur, and amateur-satellite services operating in the frequency bands 8 700-9 300 MHz and 9 900-10 500 MHz 5.2 Power flux-density levels
47、 due to active spaceborne sensors The characteristics of the various types of active spaceborne sensors as shown in Table 1 indicate that the transmitted peak power and therefore the power levels received at the Earths surface will vary significantly. Table 3 shows the active sensor pfd levels at th
48、e Earths surface for some typical sensor configurations. TABLE 3 Typical pfd levels at Earths surface Parameter Sensor type SAR Altimeter Scatterometer Precipitation radars Cloud profile radars Transmit peak power (W) 1 500 20 100 578 630 Antenna gain (dBi) 36.4 43.3 34 47.7 63.4 Altitude (km) 695 1
49、 344 1 145 350 400 pfd (dB(W/m2) 59.67 77.25 78.17 46.55 31.64 6 Rec. ITU-R RS.2105-0 5.3 Dynamics of antenna coupling with systems of other services The viewing geometry and footprint/dynamics of the active sensors are shown in Table 1. All five types of active sensors are mounted on spacecraft looking down at the Earths surface. The SARs have a look angle, which is the angle between nadir and the beam centre, of 10 degrees to 55 degrees. The scatterometers have a look angle of about 40 degrees from nadir. The altimeters, precipitati
