Characteristics of data relay satellite systems




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Rec. ITU-R SA.1414

RECOMMENDATION ITU-R SA.1414

CHARACTERISTICS OF DATA RELAY SATELLITE SYSTEMS

(Questions ITU-R 117/7, ITU-R 118/7 and ITU-R 135/7)


(1999)
Rec. ITU-R SA.1414

The ITU Radiocommunication Assembly,



considering

a) that data relay satellite (DRS) systems operate as described in Recommendation ITU-R SA.1018 – Hypothetical reference system for systems comprising data relay satellites in the geostationary orbit and user spacecraft in low-Earth orbits;

b) that there is an increase in mission requirements and in space research activity conducted particularly in low-Earth orbit;

c) that DRS provide support to many programmes/missions in the space research service and are vital to supporting both manned and unmanned space research telecommunications;

d) that it is necessary to establish relevant criteria for sharing between DRS systems and other services operating in co-frequency bands;

e) that the technical characteristics of representative DRS systems need to be considered in order to derive relevant sharing criteria,



recommends

1 that the characteristics of DRS systems, as described in Annex 1, may be used in interference sharing studies;

2 that the information provided in Annex 1 also be used as a guidance for deriving sharing criteria and coordination thresholds as appropriate for DRS systems.

ANNEX 1


TABLE 1

Forward Earth-to-DRS feeder link characteristics

Transmitting earth station

Network

Russia

United States of America

Europe

Japan

Location

Russia

United States of America(1)

Europe

Japan

Frequency range (GHz)

14.5-15.34 selectable

14.5-15.34
selectable

28.6-29.8
selectable

29.5-31
selectable

Link description

Composite(2)

Composite(2)

Decentralized(3)

Decentralized(3), (4)

Transmission rate

 256 kbit/s

 51Mbit/s

 10 Mbit/s

 50 Mbit/s

Modulation

FM(TV), PSK

PSK

PSK

Polarization

Circular

Linear

Linear

Circular

Antenna size (m)

16

18.3

3 and 9

5, 9.2 and 13

Tx antenna gain (dBi)

62

66.4

57.6 and 67.6

63, 68.2 and 71.4

Tx antenna radiation pattern

RR Appendix S7

Necessary bandwidth (MHz)

 50.5

650 (composite)

 100

 978 (composite)

Maximum power density (dB(W/Hz))

–56

–58

–38

–32.5

Maximum e.i.r.p. density (dB(W/Hz))

4

8.4

19.6

38.9

Receiving DRS

Orbital locations

Rec. ITU-R SA.1275 or Rec. ITU-R SA.1276

Antenna size (m)

1.6

2.2

0.4

2.0

Rx antenna gain (dBi)

43

47

40.2

53

Rx antenna radiation pattern

Rec. ITU-R S.672

System noise temperature (K)

1 500

2 537

1 305

890 and 579

Link availability (%)

99.99

99.9

99.9

Interference criterion

Rec. ITU-R SA.1155

(1) The earth station for the United States of America network is located in White Sands (New Mexico). The coordinates of the station are: 32.5N, 106.60 W.

(2) The composite link for the Russian network comprises one TV analogue channel and four sub-carriers to transmit digitally, a voice channel, a ranging channel and two data channels. The composite link for the United States of America network is composed of seven channels: One DRS command and ranging channel, one DRS pilot tone signal, one S-band (2 GHz) multiple access (S MA) link, two S band single access (S-SA) links and two Ku-band (14/11 GHz and 30/20 GHz) single access (K-SA) links.

(3) The European DRS ground system consists of 12 earth stations, including the TT&C earth station, located in different countries within Europe. The earth station communicates with the DRS through its European coverage antenna.

(4) The Japanese network employs a decentralized link concept that permits independent forward feeder links from different earth stations

TABLE 2


Forward DRS-to-spacecraft link characteristics


Transmitting DRS

Network

United States of America

Europe

Japan

United States of America

Russia

United States of America

Europe

Japan

United States of America

Orbital locations

Rec. ITU-R SA.1275 or Rec. ITU-R SA.1276

Frequency range (GHz)

2 ~ 2.1

2.025-2.11(1)

13.4-13.8

22.55-23.55

Link description

Multiple access
(S-MA) link

Single access (S-SA) link

Single Access (Ku-SA) link

Single Access (Ka-SA) link

Transmission rate (bit/s)

 300 kbit/s

 1 Mbit/s

 6 Mbit/s

 300 kbit/s

 256 kbit/s

 25 Mbit/s (US)

 10 Mbit/s

 50 Mbit/s

 25 Mbit/s

Modulation

SQPN/PSK(2)

FM(TV), PSK

PSK

Polarization

Circular

Antenna size (m)

Phased array

2.8

3.6

4.9

3

4.9

2.8

3.6

4.9

Tx antenna gain (dBi)

23

34

36.4

36.6

49

53.8

53.4

57.4

58.9

Tx antenna radiation pattern




Rec. ITU-R S.672

Necessary bandwidth (MHz)

 6

 6

30

20

 50.5

50

60

 150

50

Maximum power density (dB(W/Hz))

–54

–54.7

– 44.5

– 64

– 67

– 67.7

– 65.1

– 49.5

– 64.5

Maximum e.i.r.p. density (dB(W/Hz))

–31 (US)

–20.7

– 8.1

–24.7

–18

–13.9

–11.7

–7.9

–5.6

TABLE 2 (continued)




Receiving spacecraft

Network

United States of America

Europe

Japan

United States of America

Russia

United States of America

Europe

Japan

United States of America

Orbital locations

Mainly low-Earth orbit

Frequency range (GHz)

2 ~ 2.1

2.025-2.11(1)

13.4-13.8

22.55-23.55

Antenna size (m)

Omnidirectional, arrays

Omnidirectional, arrays, parabolic   1.5

 1.5

 1.3




 1.3

Rx antenna gain (dBi)

 1.5

 27.3

 27.1

 27.3

 44

 47

 48.9

 47

Rx antenna radiation pattern




Rec. ITU-R S.672 for high gain antenna

Rec. ITU-R S.672

System noise temperature (K)









 

 



 

Required Eb/N0 (dB)

~10

9.5

10.5

9.5

9.5

9.5

10.8

9.5

Required BER

1  10–5

1  10–6

Link reliability (%)

99.99

99.9

99.99

99.9

99.99

Interference criterion

Rec. ITU-R SA.1155

SQPN: Staggered quadriphase pseudo-random noise

(1) Transmit frequency is selectable in 5 MHz steps.

(2) Signals with low data rate transmissions will be spread by a pseudo-random noise code so as to meet pfd limits.

TABLE 3


Return spacecraft-to-DRS link characteristics


Transmitting spacecraft

Network

United States of America

Europe

Japan

United States of America

Russia

United States of America

Europe

Japan

United States of America

Orbital locations

Mainly low-Earth orbit

Frequency range (GHz)

2.285-2.290

2.200-2.290(1)

14.76-15.34

25.25-27.50

Link description

Multiple access
(S-MA) link

Single access (S-SA) link

Single access (Ku-SA) link

Single access (Ka-SA) link

Transmission rate

 3 Mbit/s

 1 Mbit/s

 12 Mbit/s

 6 Mbit/s

 512 kbit/s

 300 Mbit/s

150 Mbit/s

 300 Mbit/s

 800 Mbit/s

Modulation

SQPN/PSK(2)

FM, PSK

PSK

Polarization

Circular

Antenna size (m)

Omnidirectional, arrays

Omnidirectional, arrays, parabolic   1.5

 1.5

 1.9

 1.5

Tx antenna gain (dBi)

 15

 27.3

 27.6

 27.3

 43

 47

 49.7

 47

Tx antenna radiation pattern




Rec. ITU-R S.672 for high gain antenna

Rec. ITU-R S.672

Necessary bandwidth (MHz)

6

 6

20

12

 50.5

 225

 300

 300

 300

Maximum power density (dB(W/Hz))

–34

–51

–55.7

–38.6




–19

– 65.1

–58.8




Maximum e.i.r.p. density (dB(W/Hz))

Compliant with pfd limits







–23

–9.1



TABLE 3 (continued)




Receiving DRS

Network

United States of America

Europe

Japan

United States of America

Russia

United States of America

Europe

Japan

United States of America

Orbital locations

Recs. ITU-R SA.1275 or ITU-R SA.1276

Frequency range (GHz)

2.285-2.290

2.200-2.290(1)

14.76-15.34

25.25-27.50

Antenna size (m)

Phased array

2.8

3.6

4.9

3

4.9

2.8

3.6

4.9

Rx antenna gain (dBi)

29

34.7

37.2

36

49

53.3

53.4

58.8

58

Rx antenna radiation pattern




Rec. ITU-R S.672

System noise temperature (K)









680

907

 






Link reliability (%)

99.99

99.9

99.99

99.9

99.99

Interference criterion

Rec. ITU-R SA.1155

(1) Transmit frequency is selectable in 5 MHz steps, 100 kHz steps for Japanese DRS.

(2) Signals with low data rate transmissions will be spread by a pseudo-random noise code so as to meet pfd limits.

TABLE 4


Return DRS-to-Earth feeder link characteristics

Transmitting DRS

Network

Russia

United States of America

Europe

Japan

Orbital locations

Recs. ITU-R SA.1275 or ITU-R SA.1276

Frequency range (GHz)

10.7-10.95

13.4-14.05

18.1-21.2

19.7-21.2

Link description

Ku-band (14/11 GHz) return feeder

Ka-band (30/20 GHz) return feeder

Transmission rate (kbit/s)

 512







Modulation

FM, PSK

PSK

SQPN/PSK

Polarization

Circular

Linear

Circular

Antenna size (m)

1.6

2

0.4

2.0

Tx antenna gain (dBi)

43

46.1

40.2

49.5

Tx antenna radiation pattern

Rec. ITU-R S.672




Necessary bandwidth (MHz)

 50.5

650 (composite),
225 (dedicated)

 300

839

Maximum power density (dB(W/Hz))

– 66

–57

– 61

– 40.9

Maximum e.i.r.p. density (dB(W/Hz))

–23

–10.9

–20.8

8.6

Receiving earth station

Location

Russia

United States of America

Europe

Japan

Antenna size (m)

16

18.3

3, 9

5, 9.2 and 13

Rx antenna gain (dBi)

62

65.5

54, 63.9

59.5, 67.7

Rx antenna radiation pattern

RR Appendix S7

System noise temperature (K)

160

300

795

200

Link availability (%)

99.99

99.9

Interference criterion

Rec. ITU-R SA.1155

(1) The United States of America DRS transmits a dedicated and a composite link. Transmission rate for the dedicated link is 300 Mbit/s, for the composite link the transmission rate is on the order of 630 Mbit/s.

(2) The European and Japanese networks employ a decentralized link concept that permits independent return feeder links to different earth station.


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