Bi-static communication relay architecture

• US 6,931,232 B1
• Filed: 07/01/1997
• Issued: 08/16/2005
• Est. Priority Date: 07/01/1997
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Wolcott, James L.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US08/886,329
• Time in Patent Office: 2,968 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/427, 455/428, 455/1, 455/63, 370/316, 370/317, 342/352, 342/353, 342/357.01, 342/357.16, 342/367, 342/357.1
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18502 Airborne stations
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04H 20/02 Arrangements for relaying broadcast information

Abstract

A bi-static communication relay includes a receiver and transmitter carried by different platforms. In particular, the transmitter may be carried by a geosynchronous satellite forming a broadcast platform. The receiver is hidden on a low observable platform, such as an airborne or even a ground based platform forming a hidden platform. The location of the low observable platform is known only to legitimate users of the system. Communications between the hidden platform and broadcast platform are by way of a secure narrow beam uplink to reduce the risk of jamming. Physical separation of the receiver and transmitter essentially defeats the jammer'"'"'s high power amplifier advantage since the receiver platform is hidden from the jammer. This forces the jammer to use a low gain antenna in order to cover as much sky as possible. System users, on the other hand, can use the gain advantage of a directional antenna, since they alone have knowledge of the hidden platform'"'"'s location.

Claims

1. A bi-static satellite communication (SATCOM) relay for enabling communications between various communication terminals comprising:

a hidden platform which includes a receiver and means for enabling communications with said communications terminals for receiving data from said communication terminals and a transmitter and means for transmitting data to a broadcast platform defining an uplink;

a broadcast platform separated from said hidden platform having a receiver and means for receiving data from said hidden platform and a transmitter and means for transmitting data to said communication terminals; and

means for determining the position of said hidden platform and means for transmitting said position to said broadcast platform.

2. The bi-static SATCOM relay recited in claim 1, wherein said hidden platform is an airborne platform.

3. The bi-static SATCOM relay as recited in claim 2, wherein said airborne platform is a low observable platform.

4. The bi-static SATCOM relay as recited in claim 1, wherein said hidden platform is a ground based platform.

5. The bi-static communications relay as recited in claim 1, wherein said means for determining the position of said hidden platform is disposed on said hidden platform.

6. The bi-static communication relay as recited in claim 1, wherein said determining means includes means for determining the velocity of said hidden platform.

8. A bi-static communication relay as recited in claim 1, wherein said uplink is an optical uplink.

9. The bi-static communication relay as recited in claim 1, wherein said uplink is an RF signal.

10. The bi-static communications relay as cited in claim 1, further including means for utilizing spread spectrum techniques for said uplink to increase its resistance to jamming.

7. A bi-static satellite communication SATCOM relay, for enabling communications between various communication terminals comprising:

a hidden platform which includes a receiver and a receive antenna for enabling communications with said communication terminals for receiving data from said communication terminals and a transmitter and a transmit antenna for transmitting data to a broadcast platform defining an uplink; and

a broadcast platform having a receiver and a receive antenna for receiving data from said hidden platform and a transmitter and a transmit antenna for transmitting data to said communications terminals, wherein said hidden platform includes means for determining the position of said hidden platform defining position data and wherein said hidden platform includes means for encrypting said position data and transmitting said position data to said broadcast platform.

11. A bi-static satellite communication (SATCOM) relay for enabling communications with various communications terminals comprising:

a hidden receiver platform for receiving data from said communications terminals comprising;

a receive antenna and a receiver for receiving signals from said communication terminals;

a demodulator for demodulating said signals received by said receiving antenna defining demodulated signals;

means for providing a signal representative of the position of said hidden receiver platform defining position signals, means for encrypting said signals defining encrypted signals, a transmitter and a transmit antenna for transmitting said demodulated signals and said encrypted signals to a broadcast platform defining an uplink; and

a broadcast platform for transmitting downlinks to said communication terminals comprising;

a receive antenna and receiver and means for receiving signals from said hidden receiver platform; and

a transmit antenna and transmitter and means for transmitting said signals received from said hidden receiver platform to said communication terminals.

12. The SATCOM relay as recited in claim 11, wherein said hidden receiver platform is a low observable airborne platform.

13. The SATCOM relay as recited in claim 11, wherein said broadcast platform includes a beacon for facilitating alignment of said transmit and receive antennas on said hidden and broadcast platforms, respectively.

14. The SATCOM relay as recited in claim 11, wherein said providing means includes means for providing the attitude of said hidden receiver platform.

15. The SATCOM relay as recited in claim 14, wherein said providing means includes a global positioning system (GPS) receiver and antenna.

16. The SATCOM relay as recited in claim 14, wherein said providing means also includes an inertial unit.

17. The SATCOM relay as recited in claim 11, wherein said broadcast platform includes means to assist said communications terminals in calibrating their transmit antennas.

27. The bi-static satellite (SATCOM) relay as recited in claim 11, wherein said providing means includes means for providing a signal representative of the velocity of said hidden receiver platform and said encrypted signals also include encrypted velocity signals.

18. A communications terminal for use with a satellite communication (SATCOM) system which includes a hidden receiver platform and a separate broadcast platform, said broadcast platform adapted to transmit data and positional information regarding said hidden receiver platform to said communications terminal, said hidden receiver platform configured to receive data from said communications terminal and transmit the data to said broadcast platform, the communications terminal comprising:

means for transmitting data to said hidden receiver platform;

means for pointing said transmitting means toward said hidden receiver platform, said pointing means including means for pointing said transmitting means toward said hidden receiver platform as a function of the position data of said hidden receiver platform received from said broadcast platform; and

means for receiving data from said broadcast platform.

19. The communications terminal as recited in claim 18, wherein said communications terminal is a mobile terminal.

20. The communications terminal as recited in claim 18, wherein said communications terminal is a transportable terminal.

21. The communications terminal as recited in claim 18, wherein said communications terminal is a fixed terminal.

22. The communications terminal as recited in claim 18, wherein said communications terminal is a receive only terminal.

23. The communications terminal as recited in claim 18, wherein said pointing means includes means for providing signals representative of the position of said communications terminal.

24. The communications terminal as recited in claim 23, wherein said pointing means further includes means for providing signals representative of the attitude of said communications terminal.

25. The communications terminal as recited in claim 23, wherein said pointing means includes an inertial reference unit.

26. The communications terminal as recited in claim 18, wherein said transmitting means includes a transmit antenna and said communications terminal includes means to assist in calibrating its transmit antenna.