1、 STD-ITU-R RECMN SmL340-ENGL 1777 4855232 0530725 450 Rec. ITU-R S.1340 1 RECOMMENDATION ITU-R S.1340* SHARING BETWEEN FEEDER LINKS FOR THE MOBILE-SATELLITE SERVICE AND THE AERONAUTICAL RADIONAVIGATION SERVICE IN THE EARTH-TO-SPACE DIRECTION IN THE BAND 15.4-15.7 GHz (Question ITU-R 243/4) (1 997) T
2、he ITU Radiocommunication Assembly, considering a that Resolution 117 of the World Administrative Radio Conference (Geneva, 1995) (WARC-95) calls for studies by the ITU-R of the sharing situation between feeder links (Earth-to-space) for the mobile-satellite service (MSS) and the aeronautical radion
3、avigation service in the band 15.45-15.65 GHz; b) that the band 15.4-15.7 GHz is allocated to the aeronautical radionavigation service on a primary basis and that No. 953 (S4.10) of the Radio Regulations (RR) applies; cl that the WRC-95 has added an allocation to the fixed-satellite service (FSS) in
4、 the band 15.45-15.65 GHz for feeder links of non-geostationary (non-GSO) satellite networks in the MSS in the Earth-to-space direction; d) that the requirements for feeder links (Earth-to-space) of non-GSO satellite systems in the MSS need to be accommodated in this band; e) that emissions from sta
5、tions in the aeronautical radionavigation service can cause unacceptable interference to satellites; 9 that administrations operating stations in the aeronautical radionavigation service are urged to limit the average e.i.r.p. to 42 dBW in order to limit interference to non-GSO satellites; this valu
6、e is subject to review and study by the ITU-R (see RRNo. S5.511C); s) that coordination of emissions from aeronautical radionavigation stations with feeder-link space stations is not considered practical; h) that emissions from feeder-link earth stations propagated along the Earths surface can cause
7、 harmful interference to aeronautical radionavigation stations; j) that certain limitations have been placed on the fixed-satellite service for the protection of the aeronautical radionavigation service in accordance with RR No. S5.51 IC; k) that there is fairly extensive use of this band by the aer
8、onautical radionavigation service for airborne, land and ocean based stations; 1) that aircraft stations are not permitted to transmit in the band 15.45-16.45 GHz in accordance with RR No. S5.511B; m well known; n 0) earth stations and aeronautical radionavigation stations in order to protect the ae
9、ronautical radionavigation stations; P) that the technical and operational characteristics of the aeronautical radionavigation stations are reasonably that the technical and operational characteristics of feeder links are not well defined; that methods are needed to determine the coordination and se
10、paration distances required between feeder-link that studies have been made with respect to the preceding considerings, * This Recommendation should be drawn to the attention of Radiocommunication Study Group 8. STD-ITU-R RECMN S-13qO-ENGL 1777 Li855212 053072b 377 9 2 Rec. ITU-R S.1340 recommends 1
11、 2 exceed the following: that feeder links for the MSS should be limited to the band 15.43-15.63 GHz (see Note 1); that the emissions expressed as effective e.i.r.p. (Ee,) from aeronautical radionavigation stations should not 2.1 for aircraft landing systems and for feeder-link bandwidths greater th
12、an 3 MHz: 53 dBW for 01p8 53 - 0.833 (p - 8) dBW for 8 I cp 14 48 dBW for 14 I cp 32 48 - 9 (9 -32) dBW for 32 5 cp 34 30 dBW for 34 I cp 40 30 - 0.2 (9 - 40) dBW for 40 I cp I 90 2.2 for general purpose aircraft radars and for feeder-link bandwidths greater than 1 MHz: 62 dBW for O I cp 20 62 - 0.5
13、6(cp-20)2 dBW for 20 I p 25 Eef = 48 dBW for 25 I cp 29 71.86 - 25 log(cp - 20) dBW for 29 I cp 68 dBW for 68 I p I 90 I 29.8 where: Eef = Ep - 15 log (1 + 5/PW) dBW Ee: e.i.r.p. which causes the same level of interference to a phase modulated signal as a continuous noise like interferer E, : P W: c
14、p : peak pulse e.i.r.p. (dBW) of the aeronautical radionavigation station pulse duration (ps) of the aeronautical radionavigation station angle of elevation (degrees) above the local horizontal plane; 3 defined in recommends 2; 4 satellite receiving stations is not required; 5 54 dB(W/MHz) (see Note
15、 2); 6 7 interference from feeder-link earth station emissions are: that feeder links in the Earth-to-space direction should be designed to operate in the interference environment that with recommends 2 and 3 coordination of emissions from aeronautical radionavigation stations with that the e.i.r.p.
16、 transmitted toward the local horizontal plane by a feeder-link earth station should not exceed that surface based radars as described in Annex 1 should not operate in the 15.43-1 5.63 GHz band; that the coordination distances required to protect the aeronautical radionavigation stations from harmfu
17、l - - - 8 NOTE 1 -The frequency band given in recommends 1 is slightly different to that allocated by the WRC-95. This difference is recommended to facilitate sharing between the non-GSO MSS feeder links and the aeronautical radionavi- gation service. Recommends 1 will be reviewed at a later date in
18、 accordance with the outcome of a future WRC. NOTE 2 - Additional design and operational constraints may be placed on MSS Earth-to-space feeder links in order to take into account the threshold levels for the radio astronomy service given in Recommendation ITU-R RA.769. 5 15 km from the aircraft lan
19、ding surface for aircraft landing systems (ALS); 600 km from aircraft using general purpose radars (MPR); 270 km from the aircraft landing for radar sensing and measurement systems; that additional information is contained in Annexes 1, 2 and 3. STD-ITU-R RECMN SaL340-ENGL 1997 4855212 0530927 223 R
20、ec. ITU-R S. 1340 3 ANNEX 1 Aeronautical radionavigation systems in the 15.4-15.7 GHz band 1 Surface based radars (SBR) The land and ship based SBR are used for the detection, location and movement of aircraft and other vehicles on the surface of airports and other aircraft landing areas. 1.1 Antenn
21、a patterns - Nominal 3 dB beamwidth: 3.5“ vertical, inverted cosecant to -3 1 O 0.35 horizontal Frequency range: 15.65-16.7 GHz Polarization: circular Typical gain: 43 dBi Maximum side-lobe level: 25 dB below peak gain Maximum back-lobe level: 35 dB below peak gain Vertical tilt range: k 1 -5 Maximu
22、m horizontal scan range: 360“. 1.1.1 Antenna elevation envelope pattern Based on measured data and side-lobe level specifications and with the peak gain directed at +1.5“, an elevation envelope gain pattern is defined as follows where cp is the elevation angle (degrees): 43 dBi for Ocp4 43 - S(cp-4)
23、 dBi for 41cp9 G(cp) = 18 dBi for 9 I cp 16 43.2 - 21 logv dBi for 16 I cp 48 dBi for 48 I cp I 90 ! 8 1.1.2 Antenna azimuth envelope pattern Based on measured data and side-lobe level specifications, the azimuth gain pattern is defined as follows where x is the relative azimuth angle (degrees): 43
24、- 110cp2 dBi for O I cp 0.4767 18 dBi for 4.4767 I p 0.72 17.07 - 6.5 log cp dBi for 0.72 I p 48 8 dBi for 48 I cp I 180 1.2 Other characteristics 1.2.1 Transmitting - Peak e.i.r.p.: 86 dBW - - Pulse duration: 0.04 ps - Pulse repetition frequency: 8 i 92 Hz Pulse 3.5 dB bandwidth: 25 MHz. I .2.2 Rec
25、eiving - - Typical antenna gain: 43 dBi Typical noise figure: 6.2-6.9 dB. STD*ITU-R RECMN S-13iU-ENGL 1777 m i855232 0530728 IbT m G(cp) = 4 Rec. ITU-R S.1340 33 dB i for Ocp8 33 - 0.833( -8) dBi for 8 cp 14 28 dBi for 14 5 cp 32 28 - 9(cp-32) dB i for 32 5 cp 34 10 dBi for 34 I p 40 10 - 0.2 (9 - 4
26、0) dBi for 40 I cp I 90 2 Aircraft landing systems (ALS) These ALS are general purpose systems and are used on ships, as portable or permanent land based systems and for shuttle landings. The microwave scanning beam landing system (MSBLS) is one such system. Some of the characteristics vary with the
27、 particular applications. 2.1 Surface based station antenna patterns The antenna patterns are similar for all applications including the MSBLS. The scanning ranges vary with application. The scanning ranges given below cover all applications. The antenna complement of the ALS consists of an elevatio
28、n antenna and an azimuth antenna, The elevation antenna portion of the ALS is used to transmit vertical angle data to the aircraft. - nominal 3 dB beamwidths: 1.3“ vertical 40“ horizontal - frequency range: 15.4-15.7 GHz - polarization: horizontal and vertical - typical gain: 28 dBi - - maximum side
29、-lobe level: 17 dB below peak gain in both planes maximum vertical scan range: O to 30“. The azimuth antenna portion of the ALS is used to transmit azimuth information to the aircraft. nominal 3 dB beamwidths: 2.0“ horizontal 6.5“ vertical the vertical pattern is spoiled to achieve at least a 20 dBi
30、 gain at 20“ above the horizon frequency range: 15.4-15.7 GHz polarization: horizontal and vertical typical gain: 33 dBi maximum side-lobe level: 17 dB below peak gain in both planes maximum horizontal scan range: rt 35“. 2.1.1 Combined antenna elevation envelope pattern A combined vertical envelope
31、 gain pattern based on measured data is defined as follows where cp is the elevation angle (degrees): 2.1.2 Azimuth antenna patterns The azimuth envelope pattern of the elevation antenna is defined as follows where p is the relative azimuth angle (degrees): STD-ITU-R RECMN S*33qU-ENGL L997 4855232 0
32、530929 OTb Rec. ITU-R S.1340 5 The azimuth envelope pattern of the azimuth antenna is defined as follows where cp is the relative azimuth angle (degrees): 33 - 292 dBi for OIcp 3 dBi for 3Icp 5 - 25 logcp dBi for 5 I cp 48 -9.53 dBi for 48 I p I 180 G(0) = 2.2 Other characteristics 2.2.1 Transmittin
33、g - Peak e.i.r.p.: 71 dBW - - Pulse duration: 0.333 ps - Pulse repetition frequency: 3 334 Hz Pulse 3.5 dB bandwidth: 3 MHz. 2.2.2 Receiving - - Typical antenna gain: 8 dBi Typical noise figure: 8 dB. 3 Aircraft multipurpose radars (MPR) The aircraft MPR is a radionavigation, radiolocation and weath
34、er radar. 3.1 Antenna patterns The antenna is a parabola of approximately 0.3 metre diameter which is scanned vertically and horizontally with respect to the heading and attitude of the aircraft: - nominal 3 dB beamwidth: 4.5“ - frequency range: 15.4- 15.7 GHz - polarization: vertical - typical gain
35、: 30 dBi - - The envelope pattern of the antenna is defined as follows where p is the relative azimuth angle (degrees): maximum horizontal scan range: I45“ maximum vertical scan range: k 20. 30 dBi for 0 I cp 20 30 - 0.56(cp - 20)* dBi for 20 5 cp 25 G(cp) = 16 dBi for 25 I cp 29 39.86 - 25 log (9 -
36、20) dBi for 29 I cp 68 dBi for 68 I cp 5 180 I -2 17 3.2 Other characteristics 3.2.1 Transmitting - Peak e.i.r.p.s: 70 dBW - - Pulse duration: 2 ps - Pulse repetition frequency: 800 Hz Pulse 3.5 dB bandwidth: 0.5 MHz. 3.2.2 Receiving - - Typical antenna gain: 30 dBi Typical noise figure: 8 dB. 4 Rad
37、ar sensing and measurement system (RSMS) Measurement techniques using radar technology at 15 GHz are particularly suited to smaller aircraft, including helicopters, offering the benefits of compact, light, equipment with good antenna directivity and more than adequate performance for many operationa
38、l radionavigation applications which are not practicable at lower frequencies due to propagation or other reasons. For use in a height measurement mode this higher frequency band confers system design benefits, such as lower cross coupling and absence of triangulation effects, which are particularly
39、 important for accurate measurement at very low (metric) separations. For some operational applications they present the only viable technical solution. Systems using these techniques are widely used in certain parts of the world where they make an important contribution to the safety of aircraft op
40、eration. Measurement of height and ground clearance is one of the most critical parameters in the operation of aircraft when used to assist the final stages in a landing. High accuracy and interference free operation are vital to success and the enhancement of safety. RSMS are essentially used in lo
41、w level operations up to a nominal height of around 1500 m. An antenna mounting which transmits and receives vertically downwards would be used in the great majority of applications. Power reduction proportional to height above terrain is employed to reduce scatter and other undesirable effects. 4.1
42、 RSMS characteristics 4.1.1 Transmitter - - Peak power: 30 dBmW - - - - Duty cycle (max.): 3% - Frequency range: 15.63- 15.65 GHz Antenna gain: 13 dBi, back lobes 5 dBi PRF (pulse repetition frequency): 58 kHz Pulse length (max.): 500 ns Pulse 3.5 dB bandwidth: 2 MHz. 4.1.2 Receiver - - Noise figure
43、: 6 dB. Antenna gain: 13 dBi, back lobes 5 dBi ANNEX 2 Emission criteria for the aeronautical radionavigation service and sharing feasibility with feed links for the MSS (Earth-to-space) in the 15.4-15.7 GHz band 1 Introduction A basic method for protecting non-GSO satellites from unacceptable inter
44、ference is to establish maximuin limits on the e.i.r.p. from aeronautical radionavigation stations and minimum e.i.r.p. limits on the emissions from the feeder-link earth stations. Alternatively, only maximum e.i.r.p. limits on the aeronautical radionavigation stations can be established which defin
45、e the interference environment in which the feeder links must be able to operate. This alternative appears more attractive STD*ITU-R RECMN S-1340-ENGL 3977 4855232 0530933 754 = 7 Rec. TU-R S.1340 in that it is simpler and allows maximum freedom for the design and operation of feeder links. This app
46、roach is addressed in the following sections. Either of these methods is an effective way to eliminate the need for coordination. Coordination is not practical for this case. 2 Characteristics of aeronautical radionavigation systems Several systems are identified that operate in this band. These inc
47、lude surface based radars (SR) used on land and ships for the detection, location and movement of aircraft and other vehicles on aircraft landing areas, ALS, MPR and RSMS. The antenna patterns of these systems is an important element in determining the e.i.r.p. as a function of elevation angle. Ante
48、nna envelope gain patterns and other pertinent characteristics are given in Annex 1. 3 Analyses 3.1 Pulsed interference into digital carriers Task Group 4/4 studied the interference from radars into digital carriers. Measurements were made over a wide range of pulse repetition frequencies (PRF), (1-
49、100 kHz) and duty cycles, d, (0.01%-100%) for radar and data rates from 2 MBitIs to 45 MBits for 3/4 rate forward error correction (FEC) coded QPSK digital carriers operating at a bit error rate (BER) of 1 x An empirical equation was developed from the measurement data which can be used to relate the peak pulsed radar e.i.r.p., Ep, to an effective e.i.r.p., Eefi i.e., an e.i.r.p. which would cause the same level of interference (see Recommendation ITU-R S.1068). The actual average e.i.r.p., Eave, is equal to the peak e.i.r.p. times the duty cycle. Under these
