System and method to determine burst transmission timing for data communications using radar

• US 7,538,713 B1
• Filed: 11/03/2006
• Issued: 05/26/2009
• 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:
  US11/592,377
• Time in Patent Office: 935 Days
• Field of Search: 342/57, 342/58, 342/60
• 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 method for transmitting bursts of data from a communications terminal to a mobile radar transceiver having inter-burst periods is disclosed. The method includes determining a propagation time between the communications terminal and mobile radar transceiver. A length of inter-burst periods of the mobile radar transceiver having an inter-burst timing can be determined. Bursts of data having a communication burst period that is less than the inter-burst period can be formed. The bursts of data from the communications terminal can be transmitted at a transmission time based on the inter-burst timing and the propagation time to enable each burst of data to be received by the mobile radar transceiver during one of the inter-burst periods.

Claims

1. A method of transmitting bursts of data from a communications terminal to a mobile radar transceiver having inter-burst periods, comprising:

determining a propagation time between the communications terminal and the mobile radar transceiver;

establishing a length of inter-burst periods of the mobile radar transceiver having an inter-burst timing;

forming bursts of data having a communication burst period that is less than the inter-burst period;

transmitting the bursts of data from the communications terminal at a transmission time based on the inter-burst timing and the propagation time to enable each burst of data to be received by the mobile radar transceiver during one of the inter-burst periods;

receiving at the mobile radar transceiver during one of the inter-burst periods a burst of data from the communications terminal; and

receiving at the mobile radar transceiver during a different one of the inter-burst periods a reflection of a radar pulse transmitted from the mobile radar transceiver.

2. A method as in claim 1, wherein determining the propagation time further comprises transmitting a position and trajectory of the mobile radar transceiver to the communications terminal using the mobile radar transceiver.

3. A method as in claim 1, wherein determining the propagation time further comprises transmitting a change in at least one of trajectory and speed of the mobile radar transceiver to the communications terminal.

4. A method as in claim 1, wherein determining the propagation time further comprises transmitting a position and trajectory of the mobile radar transceiver to the communications terminal using a location transmitter.

5. A method as in claim 1, wherein determining the propagation time further comprises measuring the propagation time between the communications terminal and the mobile radar transceiver using a separate radar located about the communications terminal.

6. A method as in claim 1, wherein establishing the inter-burst period timing further comprises transmitting at least two radar bursts from the mobile radar transceiver to the communications terminal, wherein the at least two radar bursts are separated by the inter-burst period to enable the communications terminal to determine a start time for the inter-burst period.

7. A method as in claim 6, wherein transmitting the at least two radar bursts further comprises transmitting at least two radar bursts, wherein the radar bursts include data modulated onto the radar bursts to form modulated radar burst signals.

8. A method as in claim 1, wherein establishing the inter-burst period timing further comprises transmitting a radar clock signal from the mobile radar transceiver to the communications terminal, wherein the radar clock signal is used to determine a start time for the inter-burst periods.

9. A method as in claim 1, wherein establishing the inter-burst period timing further comprises using a common clock reference for the communications terminal and the mobile radar receiver to enable the communications terminal to determine a start time for the inter-burst periods.

10. A method as in claim 9, wherein the common clock reference is a clock reference received from a plurality of global positioning satellites.

11. A method as in claim 1, wherein forming bursts of data further comprises forming bursts of data having a communication burst period that is substantially equal to the inter-burst period.

12. A method as in claim 11, further comprising adding a guard period to at least one of a beginning and an end of the communication burst period.

13. A method as in claim 1, wherein forming bursts of data further comprises forming bursts of data having a communication burst period length that is greater than half of the inter-burst period.

14. A method as in claim 1, wherein transmitting the bursts of data further comprises relaying the bursts of data by re-transmitting the bursts of data with the mobile radar transceiver to an additional receiver.

15. A method as in claim 1, further comprising adding a sync word to the burst of data transmitted from the communications terminal to enable a clock reference at the mobile radar transceiver to be substantially synchronized with the burst of data.

16. A method as in claim 1, wherein transmitting the bursts of data further comprises transmitting the bursts of data having burst lengths less than 500 microseconds.

17. A method as in claim 1, wherein transmitting the bursts of data further comprises transmitting the bursts of data having burst lengths less than 25 microseconds.

18. A method as in claim 1, wherein transmitting the bursts of data further comprises transmitting the bursts of data having at least 1500 symbols modulated onto each burst of data.

19. A method as in claim 1, wherein transmitting the bursts of data further comprises transmitting the bursts of data having at least 300 symbols modulated onto each burst of data.

20. A system for transmitting bursts of data from a communications terminal to a mobile radar transceiver, comprising:

a propagation delay device to determine a propagation time between the mobile burst radar and a communications terminal;

an inter-burst timing device to establish timing and length of inter-burst periods of the mobile burst radar;

a transmitter disposed in the communications terminal and coupled to the propagation delay device and the inter-burst timing device to enable the transmitter to transmit a burst of data to be received by the mobile burst radar during the inter-burst period; and

a receiver disposed in the mobile radar transceiver and configured to receive during different inter-burst periods reflections of radar bursts transmitted from the mobile radar transceiver and receive data transmitted from the communications terminal.

21. A means for transmitting bursts of data from a communications terminal to a mobile radar transceiver having inter-burst periods, comprising:

a determining means for determining a propagation time between the communications terminal and mobile radar transceiver;

a timing means for establishing a length of inter-burst periods of the mobile radar transceiver having an inter-burst timing;

a transmission means disposed within the communications terminal for transmitting bursts of data having a length less than or equal to the length of the inter-burst periods from the communications terminal at a transmission time based on the inter-burst timing and the propagation time to enable each burst of data to be received by the mobile radar transceiver during one of the inter-burst periods; and

a reception means disposed within the mobile radar transceiver for receiving reflections of radar bursts transmitted from the mobile radar transceiver and receiving the burst of data from the communications terminal during different inter-burst periods.