System and method for suppressing close clutter in a radar system

• US 7,969,349 B2
• Filed: 04/06/2009
• Issued: 06/28/2011
• Est. Priority Date: 04/06/2009
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Holzheimer, Timothy R., Goodman, Vernon R.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Brainard; Timothy A
• Application Number:
  US12/418,958
• Publication Number:
  US 20100253573A1
• Time in Patent Office: 813 Days
• Field of Search: 342 27- 28, 342/176
• US Class Current: 342/176
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93273 on the top of the vehicles
• CPC Class Codes: G01S 2013/93275 in the bumper area
• CPC Class Codes: G01S 7/40 Means for monitoring or calibrating
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter

Abstract

A system for processing electromagnetic waves in a radar system is disclosed. The system includes a transmitter operable to transmit operating waves and calibration waves, one or more receivers operable to receive reflected calibration waves and operating waves, and a system controller operable to process the received calibration waves and operating waves. The system controller may process the received waves by generating a threshold signal based on the calibration waves, and comparing the threshold signal to the operating waves. The system controller may also process operating waves and calibration waves in accordance with one or more signal conditioning algorithms. Additionally, the system controller may display an image representing a target on a display by comparing received operating waves with the generated threshold signal.

Claims

1. A method for processing radio frequency signals, comprising:

transmitting a first transmitted calibration radio frequency (RF) signal into a background environment in which no targets are present;

receiving a first received calibration (RF) signal associated with the first transmitted calibration RF signal, the first received calibration RF signal reflected from the background environment and indicative of the environment in which no targets are present;

generating a first threshold signal based at least in part on the first received calibration RF signal;

transmitting a second transmitted operation RF signal;

receiving a second received operation RF signal associated with the second transmitted RF signal; and

generating a display based on, at least in part, the first threshold signal and the second received operation RF signal.

2. The method of claim 1, wherein generating a display comprises generating a display based on subtracting the first threshold signal from the second received RF signal.

3. The method of claim 1, wherein receiving a first received RF signal comprises receiving the first received RF signal during a predetermined length of time, and wherein generating a first threshold signal comprises generating the first threshold signal corresponding to the predetermined length of time, and wherein receiving a second received RF signal comprises receiving the second received RF signal during the predetermined length of time.

4. The method of claim 1, further comprising:

transmitting a third transmitted RF signal;

receiving a third received RF signal associated with the third transmitted RF signal; and

generating a second threshold signal based, at least in part, on the third received RF signal.

5. The method of claim 4, wherein generating the second threshold signal comprises combining the first received RF signal and the third received RF signal.

6. The method of claim 4, wherein generating the second threshold signal comprises averaging the first received RF signal and the third received RF signal.

7. The method of claim 1, wherein generating the first threshold signal comprises:

modifying the phase of the first received RF signal;

modifying the amplitude of the first received RF signal; and

generating the first threshold signal based on the modified first received RF signal.

8. The method of claim 1, wherein generating the display comprises:

receiving the first received RF signal comprises receiving, at each of a plurality of receivers, a received RF signal associated with the first transmitted RF signal;

generating the threshold signal comprises generating a plurality of threshold signals, wherein each threshold signal is generated based at least in part on one of the received RF signals associated with the first transmitted RF signal;

receiving the second received RF signal comprises receiving, at each of the plurality of receivers, a received RF signal associated with the second transmitted RF signal; and

generating the display comprises generating a multi-dimensional display based at least in part on the received RF signals associated with the second transmitted RF signal and the threshold signals.

9. A radio frequency signal processing system comprising:

a transmitter operable to;

transmit a first transmitted calibration radio frequency (RF) signal into a background environment in which no targets are present; and

transmit a second transmitted operation RF signal;

a first receiver operable to;

receive a first received calibration RF signal associated with the first transmitted calibration RF signal, the first received calibration RF signal reflected from the background environment and indicative of the background environment in which no targets are present; and

receive a second received operation RF signal associated with the second transmitted RF signal; and

a processor operable to;

generate a first threshold signal based, at least in part, on the first received calibration RF signal; and

generate a display based on, at least in part, the second received operation RF signal and the first threshold signal.

10. The system of claim 9, wherein the processor is operable to generate a display by generating a display based on subtracting the first threshold signal from the second received RF signal.

11. The system of claim 9, wherein the receiver is operable to:

receive the first received RF signal by receiving the first received RF signal during a predetermined length of time; and

receive the second received RF signal by receiving the second received RF signal during the predetermined length of time; and

wherein the processor is operable to generate the first threshold signal by generating the first threshold signal corresponding to the predetermined length of time.

12. The system of claim 9, wherein the transmitter is further operable to transmit a third transmitted RF signal;

and

wherein the receiver is further operable to receive a third received RF signal associated with the third transmitted RF signal; and

wherein the processor is further operable to generate a second threshold signal based, at least in part, on the third received RF signal.

13. The system of claim 12, wherein the processor is operable to generate the second threshold signal by combining the first received RF signal and the third received RF signal.

14. The system of claim 12, wherein the processor is operable to generate the second threshold signal by averaging the first received RF signal and the third received RF signal.

15. The system of claim 9, wherein the processor is operable to generate the first threshold signal by:

modifying the phase of the first received RF signal;

modifying the amplitude of the first received RF signal; and

generating the first threshold signal based on the modified first received RF signal.

16. The system of claim 9, wherein:

the first receiver comprises one of a plurality of receivers; and

the processor is operable to;

receive the first received RF signal by receiving, at each of the plurality of receivers, a received RF signal associated with the first transmitted RF signal;

generate the threshold signal by generating a plurality of threshold signals, wherein each threshold signal is generated based at least in part on one of the received RF signals associated with the first transmitted RF signal;

receive the second received RF signal by receiving, at each of the plurality of receivers, a received RF signal associated with the second transmitted RF signal; and

generate the display by generating a multi-dimensional display based at least in part on the received RF signals associated with the second transmitted RF signal and the threshold signals.

17. Logic for processing radio frequency signals, the logic encoded on tangible media and operable, when executed on a processor to:

transmit a first received calibration radio frequency (RF) signal into a background environment in which no targets are present;

receive a first received calibration RF signal associated with the first transmitted calibration RF signal, the first received calibration RF signal reflected from the background environment and indicative of the environment in which no targets are present;

generate a first threshold signal based at least in part on the first received calibration RF signal;

transmit a second transmitted operation RF signal;

receive a second received operation RF signal associated with the second transmitted RF signal; and

generate a display based on, at least in part, the second received RF signal and the first threshold signal.

18. The logic of claim 17, wherein the logic is operable to generate a display by generating a display based on subtracting the first threshold signal from the second received RF signal.

19. The logic of claim 17, wherein the logic is operable to:

receive a first received RF signal by receiving the first received RF signal during a predetermined length of time;

generate a first threshold signal by generating the first threshold signal corresponding to the predetermined length of time; and

receive a second received RF signal by receiving the second received RF signal during the predetermined length of time.

20. The logic of claim 17, wherein the logic is further operable to:

transmit a third transmitted RF signal;

receive a third received RF signal associated with the third transmitted RF signal; and

generate a second threshold signal based, at least in part, on the third received RF signal.

21. The logic of claim 20, wherein the logic is operable to generate the second threshold signal by combining the first received RF signal and the third received RF signal.

22. The logic of claim 20, wherein the logic is operable to generate the second threshold signal by averaging the first received RF signal and the third received RF signal.

23. The logic of claim 17, wherein the logic is operable to generate the first threshold signal by:

modifying the phase of the first received RF signal;

modifying the amplitude of the first received RF signal; and

generating the first threshold signal based on the modified first received RF signal.

24. The logic of claim 17, wherein the logic is operable to:

receive the first received RF signal by receiving, at each of a plurality of receivers, a received RF signal associated with the first transmitted RF signal;

generate the threshold signal by generating a plurality of threshold signals, wherein each threshold signal is generated based at least in part on one of the received RF signals associated with the first transmitted RF signal;

receive the second received RF signal by receiving, at each of the plurality of receivers, a received RF signal associated with the second transmitted RF signal; and

generate the display by generating a multi-dimensional display based at least in part on the received RF signals associated with the second transmitted RF signal and the threshold signals.

25. A system for processing radio-frequency signals, comprising:

means for transmitting a first transmitted calibration RF signal into a background environment in which no targets are present;

means for receiving a first received calibration RF signal associated with the first transmitted calibration RF signal, the first received calibration RF signal reflected from the background environment and indicative of the environment in which no targets are present;

means for generating a first threshold signal based at least in part on the first received calibration RF signal;

means for transmitting a second transmitted operation RF signal;

means for receiving a second received operation RF signal associated with the second transmitted RF signal; and

means for generating a display based on, at least in part, the second received operation RF signal and the first threshold signal.