MULTISTATIC TARGET DETECTION AND GEOLOCATION

• US 20120056772A1
• Filed: 03/04/2011
• Published: 03/08/2012
• Est. Priority Date: 05/04/2010
• Status: Active Grant

• Current Assignee: Amin G. Jaffer, David G Miranda
• Original Assignee: Amin G. Jaffer, David G Miranda
• Inventors: Jaffer, Amin G., Miranda, David G.
• Granted Patent: US 8,730,092 B2
• Time in Patent Office: Days
• US Class Current: 342/99
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36

Abstract

Aspects of this invention are directed to the substantially improved detection and geolocation accuracy of targets (stationary or moving) by using the coherent data received at multiple airborne sensors. Further aspects are directed to aligning the (unknown) time-delayed and Doppler-shifted signals received at the multiple sensors relative to an arbitrary reference sensor, which depend on the unknown target position. This results in the target position and velocity vectors being simultaneously estimated and the detection peak enhanced by obtaining near coherent gain. Still further aspects are directed to the coherent generalized likelihood ratio test (GLRT) and the minimum variance distortionless response (MVDR) statistic for multistatic radar systems, conditioned on estimation of certain parameters that render the system coherent. Analytical and computer simulation results are presented to show substantially enhanced detection and geolocation of moving targets in clutter.

Claims

1. A multistatic radar system comprising:

a transmitter for transmitting signals to reflect off a target;

a plurality of spatially separated receivers for receiving the reflected signals from the target; and

a signal processor for fusing the received reflected signals from the receivers,

wherein the fusing of the received reflected signals comprises;

aligning the received reflected signals in time delay and Doppler shift; and

summing the resulting aligned signals to detect or geolocate the target.

2. The multistatic radar system of claim 1, wherein the summing of the resulting aligned signals comprises non-coherently summing the resulting aligned signals.

3. The multistatic radar system of claim 2, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises generating and applying a non-coherent Generalized Likelihood Ratio Test (GLRT) statistic.

4. The multistatic radar system of claim 1, wherein the summing of the resulting aligned signals comprises coherently summing the resulting aligned signals.

5. The multistatic radar system of claim 4, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises generating and applying a coherent Generalized Likelihood Ratio Test (GLRT) statistic.

6. The multistatic radar system of claim 4, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises generating and applying a coherent minimum variance distortionless response (MVDR) statistic.

7. The multistatic radar system of claim 1, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises modeling location and velocity vectors of the target.

8. The multistatic radar system of claim 1, wherein the fusing of the received reflected signals comprises representing a state vector of the target in a centralized Cartesian coordinate system over all receivers.

9. The multistatic radar system of claim 1, wherein the detection or geolocation of the target is decided when the summing of the resulting aligned signals exceeds a threshold.

10. The multistatic radar system of claim 1, wherein the target comprises a moving target in clutter, and the fusing of the received reflected signals comprises detecting or geolocating the target in the clutter.

11. A method of detection and geolocation of a target by a multistatic radar system comprising a transmitter, a plurality of spatially separated receivers, and a signal processor, the method comprising:

transmitting signals from the transmitter to the target, producing reflected signals off the target;

receiving the reflected signals in the receivers; and

fusing the received reflected signals, comprising;

aligning the received reflected signals in time delay and Doppler shift; and

summing the resulting aligned signals to detect or geolocate the target.

12. The method of claim 11, wherein the summing of the resulting aligned signals comprises non-coherently summing the resulting aligned signals.

13. The method of claim 12, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises generating and applying a non-coherent Generalized Likelihood Ratio Test (GLRT) statistic.

14. The method of claim 11, wherein the summing of the resulting aligned signals comprises coherently summing the resulting aligned signals.

15. The method of claim 14, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises generating and applying a coherent Generalized Likelihood Ratio Test (GLRT) statistic.

16. The method of claim 14, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises generating and applying a coherent minimum variance distortionless response (MVDR) statistic.

17. The method of claim 11, wherein the aligning of the received reflected signals in time delay and Doppler shift comprises modeling location and velocity vectors of the target.

18. The method of claim 11, wherein the fusing of the received reflected signals comprises representing a state vector of the target in a centralized Cartesian coordinate system over all receivers.

19. The method of claim 11, wherein the detection or geolocation of the target is decided when the summing of the resulting aligned signals exceeds a threshold.

20. The method of claim 11, wherein the target comprises a moving target in clutter, and the fusing of the received reflected signals comprises detecting or geolocating the target in the clutter.