System and method for detecting and estimating the direction of near-stationary targets in monostatic clutter using phase information

• US 6,750,804 B2
• Filed: 04/04/2002
• Issued: 06/15/2004
• Est. Priority Date: 04/04/2002
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Samuel, Alphonso A., Braunreiter, Dennis C., Chen, Hai-Wai, David, George T., Schmitt, Harry A.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US10/116,438
• Publication Number:
  US 20030189512A1
• Time in Patent Office: 803 Days
• Field of Search: 342/89-103, 342/159-164, 342/175, 342/195, 342/189-194, 342/196, 342/197, 342/25, 342/27, 342/28, 342/61, 342/62, 342/73, 342/74-81, 342/118, 342/134-144, 342/147, 342/149, 342/150, 342/151-154, 356/3, 356/4-1-, 244/3--
• US Class Current: 342/89
• CPC Class Codes: G01S 13/5244 Adaptive clutter cancellation specially adapted for airborne MTI, G01S13/5242
• CPC Class Codes: G01S 13/883 for missile homing, autodirectors missile guidance systems F41G7/22
• CPC Class Codes: G01S 7/2883 using FFT processing
• CPC Class Codes: G01S 7/2886 using I/Q processing

Abstract

A system and method for detecting a target. The inventive method includes the steps of receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component; extracting from the imaginary component information representative of the phase component of the return signal; and utilizing the phase component to detect the target. Specifically, the phase components are those found from the complex range-Doppler map. More specific embodiments further include the steps of determining a power spectral density of the phase component of the return signal; performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray (quadrant channels); and averaging the cross-correlated power spectral density of the low frequency components. In an alternative embodiment, the cross-correlation is performed on the phase component of the range-Doppler map directly. This signal can then be averaged to potentially provide improved detection of targets. The cross-correlations of the power spectral densities derived from the complex valued range-Doppler map are then used to detect the target in the presence of monostatic clutter. An additional teaching relates to a utilization of the phase component to ascertain a direction of the target and thereby effect target tracking as well as target detection.

Claims

1. A system for detecting a target in clutter comprising:

first means for receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component;

second means for extracting from the imaginary component information representative of the phase component of the return signal; and

third means responsive to the phase component for detecting the target.

2. The invention of claim 1 further including means responsive to the phase component for detecting a direction of the target.

3. The invention of claim 1 wherein the first means includes a radar receiver.

4. The invention of claim 3 wherein the second means includes means for providing a phase range-Doppler map.

5. The invention of claim 3 wherein the second means includes means for determining a power spectral density of the phase component of the return signal.

6. The invention of claim 5 wherein the second means includes means for performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray quadrant channels.

7. The invention of claim 6 wherein the second means includes means for averaging the cross-correlated power spectral density of the low frequency components of the return signal.

8. The invention of claim 1 wherein the second means includes means for performing a cross-correlation of the phase component of the return signal between different antenna-subarray quadrant channels.

9. The invention of claim 8 wherein the second means includes means for averaging the cross-correlated power spectral density of the low frequency components of the return signal.

10. The invention of claim 1 wherein the third means includes means for tracking the target.

11. A system for detecting a target in clutter comprising:

a radar receiver adapted to receive a complex return signal of an electromagnetic pulse having a real and an imaginary component;

a signal processor for extracting from the imaginary component information representative of the phase component of the return signal; and

a target detector responsive to the phase component for detecting the target.

12. A method for detecting a target in clutter including the steps of:

receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component;

extracting from the imaginary component information representative of the phase component of the return signal; and

utilizing the phase component to detect the target.

13. The invention of claim 12 further including the step of using the phase component to ascertain a direction of the target.

14. The invention of claim 12 further including the step of providing a phase range-Doppler map.

15. The invention of claim 12 further including the step of determining a power spectral density of the phase component of the return signal.

16. The invention of claim 15 further including the step of performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray quadrant channels.

17. The invention of claim 16 further including the step of averaging the cross-correlated power spectral density of the low frequency components of the return signal.

18. The invention of claim 12 further including the step of performing a cross-correlation of the phase component of the return signal between different antenna-subarray quadrant channels.

19. The invention of claim 18 further including the step of averaging the cross-correlated power spectral density of the low frequency components of the return signal.

20. The invention of claim 12 further including the step of tracking the target.