System and Method for Processing Satellite Communication Data

• US 20080287123A1
• Filed: 04/20/2006
• Published: 11/20/2008
• Est. Priority Date: 04/20/2005
• Status: Abandoned Application

• Current Assignee: ELTA Systems Limited (Government of Israel)
• Original Assignee: ELTA Systems Limited (Government of Israel)
• Inventors: Giloh, Benjamin
• Application Number:
  US11/912,065
• Publication Number:
  US 20080287123A1
• Time in Patent Office: Days
• US Class Current: 455/427
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04M 3/2281 Call monitoring, e.g. for law enforcement purposes; Call tracing; Detection or prevention of malicious calls

Abstract

The present invention provides an apparatus and method for intercepting and monitoring communications between target mobiles and a main station of a satellite communication system, wherein communication between the mobiles and a satellite is achieved by using a first-band spot beams, chosen by the mobiles and wherein communication between the satellite and the main station is achieved by using a wideband second-band link, and wherein the satellite is operable to change the mapping scheme of the first-band frequencies to the second-band frequencies, the apparatus comprises: at least one RF second-band and at least one RF first-band receive antenna which transmits the received signals to at least one RF second-band and at least one first-band receiver respectively; an intermediate frequency RF distributor which receives signals from said RF second-band and RF first-band receivers and splits the transmission into groups of frequencies; a plurality of demodulators which are tuned to cover sequentially the first-band frequency spectrum, for extracting identification codes of target mobiles and decryption messages; a wide angle mapping unit which receives the second-band signals from said intermediate frequency distributor, analyses and maps the received frequencies according to their time occurrence, and correlates said frequencies with said first-band frequencies; means for recording and monitoring said communications.

Claims

1. An apparatus for intercepting and monitoring communications between target mobiles and a main station of a satellite communication system, wherein communication between the mobiles and a satellite is achieved by using a first-band spot beams, chosen by the mobiles and wherein communication between the satellite and the main station is achieved by using a wideband second-band link, and wherein the satellite is operable to change the mapping scheme of the first-band frequencies to the second-band frequencies, said apparatus comprises:

at least one RF second-band and at least one RF first-band receive antenna which transmits the received signals to at least one RF second-band and at least one first-band receiver respectively;

an intermediate frequency RF distributor which receives signals from said RF second-band and RF first-band receivers and splits the transmission into groups of frequencies;

a plurality of demodulators which are tuned to cover sequentially the first-band frequency spectrum, for extracting identification codes of target mobiles and decryption messages;

a wide angle mapping unit which receives the second-band signals from said intermediate frequency distributor, analyses and maps the received frequencies according to their time occurrence, and correlates said frequencies with said first-band frequencies;

means for recording and monitoring said communications.

2. The apparatus according to claim 1, wherein said first-bend being L-band and said second-band being C-band.

3. The apparatus according to claim 1, wherein said satellite being the Aces.

4. An apparatus for intercepting and monitoring communications between at least one mobile device and a main station of communication system, wherein communication between the at least one mobile and a satellite is achieved by using L-band spot beams, chosen by the mobiles and wherein communication between the satellite and the main station is achieved by using a wideband Cband link, said apparatus comprises:

at least one RF C-band and at least one RF L-band receive antenna which transmits the received signals to at least one RF C-band and at least one L-band receiver respectively;

a control unit coupled to a coarse mapping unit and a. fine mapping unit;

said control unit is configured to cause said coarse mapping unit to identify substantially simultaneously a subset including at least one C-band frequency from among said C-band frequencies which subset of frequencies prima facie is mapped to an L band frequency, said identifying a subset including analysis of energy detected in said C band frequencies;

said control unit is further configured to cause said fine mapping unit to identify a C-band frequency from among said subset of frequencies which is mapped to said L band frequency.

5. The apparatus according to claim 4, wherein said fine mapping unit being a plurality of demodulators and associated processor which are tuned to cover sequentially the L-band frequency spectrum;

the number of said demodulators is considerably smaller than the number of said C band frequencies.

6. The apparatus according to claim 4, wherein said coarse mapping unit being a wide angle mapping unit and associated processor.

7. The apparatus according to claim 4, wherein said subset of C band frequencies being control frequencies, and wherein said L band frequency and identified C band frequency being control frequencies.

8. The apparatus according to claim 7, wherein said L-band frequency being BCCR and wherein said subset being RACR frequencies, and wherein said fine mapping unit identifying said mapped L band frequency and C band frequency according to identical unique spot beam number (SB_Mask) data 111 the respective control frequencies.

9. The apparatus according to claim 4, wherein said subset of C band frequencies being traffic frequencies, and wherein said L band frequency and identified C band frequency being traffic frequencies.

10. The apparatus according to claim 4, further comprising finding an Access Grant (AGCR) signal in the control channel of said downlink L band and identifying corresponding RACR signal in the control channel in said downlink C band;

said identifying including determining identical request reference signal in said AGCR and RACH signals.

11. The apparatus according to claim 10, further comprising switching to a traffic channel in said L band according to data extracted from an Access Grant (AGCH) signal found in said downlink L band, and identifying corresponding SABM signal in a channel in the downlink C band link according to a predetermined criterion;

the latter channel being the traffic channel in said downlink C band.

12. The apparatus according to claim 4, further comprising a unit for monitoring communications transmitted through said traffic frequencies.

13. The apparatus according to claim 4, wherein said L band frequencies include 1087 frequencies, and wherein said C band frequencies include 7000 frequencies.

14. The apparatus according to claim 4, wherein the number of said modulator is smaller than 100.

15. The apparatus according to claim 4, wherein said satellite being the Aces.