System and method for transmitting high data rate information from a radar system

• US 7,423,577 B1
• Filed: 11/03/2006
• Issued: 09/09/2008
• Est. Priority Date: 11/03/2005
• Status: Active Grant

• Current Assignee: L3 Technologies, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Inventors: Thomson, Larry S., McIntire, William K., Boesch, James J., Robbins, David H.
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/592,536
• Time in Patent Office: 676 Days
• Field of Search: 342/57, 375/145, 375/295
• US Class Current: 342/57
• CPC Class Codes: G01S 13/90 using synthetic aperture techniques , e.g. synthetic aperture radar [SAR] techniques
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence

Abstract

A system and method for transmitting high data rate information from a pulsed radar is disclosed. The method includes collecting information using a mobile radar platform. The information is divided into a plurality of segments. Each segment is configured to fit within a time period less than a radar burst signal time period. Each segment is modulated onto a radar burst signal to form modulated radar burst signals. The modulated radar burst signals are transmitted from the pulsed radar system.

Claims

1. A method for transmitting high data rate information from a pulsed radar system, comprising:

collecting information via radar pulse reflections of unmodulated bursts using a mobile radar platform;

dividing the information into a plurality of segments, wherein each segment is configured to fit within a time period less than a radar burst signal time period;

modulating each segment onto a radar burst signal to form modulated radar burst signals; and

transmitting the modulated radar burst signals from the radar system wherein the modulated radar burst signals are interspersed between the unmodulated bursts to provide substantially simultaneous collection and transmission of the information.

2. A method as in claim 1, further comprising modulating each segment onto the radar burst signal using a modem.

3. A method as in claim 2, wherein the modem is controlled using a gate signal provided by the radar system, wherein the gate signal corresponds to the radar burst signal time period.

4. A method as in claim 3, further comprising modulating each segment onto the radar burst signal when the gate signal is actuated.

5. A method as in claim 1, further comprising modulating each segment onto a radar burst signal during the radar burst signal time period based on a reference clock provided by the radar system.

6. A method as in claim 2, further comprising adding an end guard interval to an end of the gate signal, wherein the end guard interval has a width sufficient to ensure data transmitted during the gate signal is not clipped.

7. A method as in claim 2, further comprising adding a start guard interval to a beginning of the gate signal, wherein the start guard interval has a width sufficient to enable a power amplifier in the radar system to become substantially stable prior to data being modulated onto the radar burst signal.

8. A method as in claim 1, further comprising transmitting a synchronization sequence during the burst signal time period.

9. A method as in claim 8, further comprising transmitting the synchronization sequence to enable a receiver to acquire at least one of burst synchronization, frame synchronization, symbol timing, and file synchronization.

10. A method as in claim 8, further comprising transmitting the synchronization sequence, wherein the synchronization sequence is known to the radar system and a receiver prior to transmission of the modulated radar burst signals.

11. A method as in claim 8, further comprising transmitting the synchronization sequence, wherein the synchronization sequence is configured to be maximized when there is no offset in an autocorrelation and minimized when the autocorrelation is offset.

12. A method as in claim 1, further comprising transmitting at least one acquisition burst configured to enable a receiver to acquire symbol timing.

13. A method as in claim 12, further comprising transmitting the acquisition burst, wherein the acquisition burst comprises an idle sequence configured for rapid acquisition.

27. A method as in claim 1, wherein the collecting information comprises performing synthetic aperture radar image processing.

28. A method as in claim 1, wherein the transmitting the modulated radar burst signals comprises transmitting modulated bursts separated by an unmodulated burst.

29. A method as in claim 1, wherein the transmitting the modulated radar burst signals comprises transmitting the modulated bursts as every nth burst, other bursts being unmodulated, wherein n is a positive integer.

30. A method as in claim 1, wherein the transmitting the modulated radar burst signals comprises transmitting a group of n consecutive modulated bursts separated by at least one unmodulated burst, wherein n is a positive integer.

14. A system for transmitting high data rate information from radar equipment, comprising:

a pulsed radar mounted on a mobile radar platform configured to transmit a plurality of burst radar signals comprising interspersed modulated bursts and unmodulated bursts and to collect radar data based on the burst radar signals;

a modem coupled to the pulsed radar to form the modulated bursts and configured to receive a gate signal from the pulsed radar associated with a radar burst signal time period of the burst radar signal; and

a data source coupled to the modem to provide modulation data to the modem, wherein the modem is configured to divide the modulation data into a plurality of data segments, with each data segment configured to fit within the radar burst signal time period, wherein the modulation data is the radar data collected by the pulsed radar.

15. A system as in claim 14, wherein the modem is configured to modulate the plurality of data segments onto the plurality of radar burst signals to form modulated radar burst signals.

16. A system as in claim 15, wherein a synchronization word is added to every modulated radar burst signal.

17. A system as in claim 16, wherein the synchronization word provides less than 5 percent of the bits modulated onto a radar burst signal.

18. A system as in claim 16, wherein the synchronization word provides less than 20 percent of the bits modulated onto a radar burst signal.

19. A system as in claim 15, wherein a synchronization word is added to every nth modulated radar burst signal, where n is a positive integer.

20. A system as in claim 15, wherein greater than 1,000 symbols are transmitted during the burst signal time period.

21. A system as in claim 20, wherein the burst signal time period is less than 10 microseconds.

22. A system as in claim 20, wherein the burst signal time period is less than 200 microseconds.

23. A system as in claim 14, wherein the modem is configured to modulate the plurality of data segments onto every nth radar burst signal, wherein n is a positive integer.

24. A system as in claim 14, wherein the modem is configured to modulate the plurality of data segments onto a grouping of burst signals, wherein the grouping of burst signals is a plurality of burst signals separated by a plurality of unmodulated burst signals.

25. A system as in claim 14, wherein the pulsed radar has an equivalent isotropic radiated power of greater than 500 kilowatts.

26. A system as in claim 14, wherein the mobile radar platform is selected from the group consisting of aircraft, helicopters, lighter than air ships, ships, and ground based vehicles.

31. A system as in claim 14, wherein the pulse radar comprises a synthetic aperture radar.