System and method for reducing a radar interference signal

• US 20060125682A1
• Filed: 12/15/2004
• Published: 06/15/2006
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: Valeo Radar Systems, Inc. (Valeo SE)
• Original Assignee: Valeo Radar Systems, Inc. (Valeo SE)
• Inventors: Kelly, Thomas M. Jr., Aeder, R. Gregory, Woodington, Walter Gordon
• Granted Patent: US 7,403,153 B2
• Time in Patent Office: Days
• US Class Current: 342/159
• CPC Class Codes: G01S 13/931 of land vehicles
• 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
• CPC Class Codes: G01S 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing

Abstract

A system and method are provided to reduce an interfering signal in a radar return signal for a frequency modulated continuous wave (FMCW) radar. Once the interfering signal is detected, an extent of the interfering signal is determined and the interfering signal is removed from the radar return signal. This allows the radar to detect a target in the presence of the interfering signal. The system and method can benefit any FMCW radar that is within the range of an interfering radar source (e.g. another FMCW radar, a police radar gun, a pulse radar, etc.) operating in the same frequency band as the FMCW radar.

Claims

1. A method of processing a radar return signal, comprising:

generating time samples associated with the radar return signal; and

processing the time samples to detect an interfering signal in the time samples.

2. The method of claim 1, further including:

determining an extent of the interfering signal; and

removing the interfering signal from the time samples.

3. The method of claim 2, wherein the processing the time samples to detect an interfering signal comprises:

generating an array having array values associated with the time samples;

generating at least one threshold associated with the array values;

comparing the array values with the at least one threshold; and

detecting that the interfering signal exists if at least a selected number of array values exceed the at least one threshold.

4. The method of claim 3, wherein array values comprise a selected one of slope values, higher order derivative values, time sample absolute values, and power values associated with the time samples.

5. The method of claim 3, wherein the generating at least one threshold comprises generating at least one of a first threshold related to a maximum expected array value and second threshold related to a mean value of the array values.

6. The method of claim 5, wherein the comparing the array values with the at least one threshold comprises comparing the array values with at least one of the first threshold and the second threshold.

7. The method of claim 5, wherein the detecting that the interfering signal exists comprises identifying if at least the selected number of array values exceed at least one of the first threshold and the second threshold.

8. The method of claim 3, wherein the determining an extent of the interfering signal comprises:

identifying a lower array sample limit associated with a selected one of the selected number of array values exceeding the at least one threshold;

identifying an upper array sample limit associated with another selected one of the selected number of array values exceeding the at least one threshold;

selecting a first sample guard band value;

selecting a second sample guard band value;

subtracting the first sample guard band value from the lower array sample limit to provide an interfering signal lower array sample extent;

adding the second sample guard band value to the upper array sample limit to provide an interfering signal upper array sample extent; and

identifying at least one of an interfering signal lower time sample extent and an interfering signal upper time sample extent in accordance with the interfering signal lower array sample extent and the interfering signal upper array sample extent, respectively.

9. The method of claim 8, wherein the removing the interfering signal from the time samples comprises selecting a group of contiguous time samples excluding time samples between the interfering signal lower time sample extent and the interfering signal upper time sample extent.

10. The method of claim 9, wherein the removing the interfering signal from the time samples further includes padding the group of contiguous time samples.

11. The method of claim 8, wherein the removing the interfering signal from the time samples comprises:

generating a weighting function in accordance with the interfering signal lower time sample extent and the interfering signal upper time sample extent; and

applying the weighting function to the time samples.

12. A method of detecting an interfering signal in a radar return signal, the method comprising:

generating time samples associated with the radar return signal;

generating an array having array values associated with the time samples;

generating at least one threshold associated with the array values;

comparing the array values with the at least one threshold; and

detecting that the interfering signal exists if at least a selected number of array values exceed the at least one threshold.

13. The method of claim 12, wherein array values comprise a selected one of slope values, higher order derivative values, time sample absolute values, and power values associated with the time samples.

14. The method of claim 12, wherein the generating at least one threshold comprises generating at least one of a first threshold related to a maximum expected array value;

and a second threshold related to a mean value of the array values.

15. System to process a radar return signal, comprising:

a radar receiving module to provide a downconverted signal;

a radar signal sampling module coupled to the radar receiving module to provide time samples associated with the downconverted signal; and

an interference detector coupled to receive the time samples and to detect an interfering signal in the time samples.

16. The system of claim 15, further including:

an interference extent processor coupled to the interference detector to determine an extent of the interfering signal; and

an interference removal processor coupled to the interference extent processor to remove the interfering signal from the time samples.

17. The system of claim 15, wherein the interference detector includes an array processor to generate an array having array values associated with the time samples, to generate at least one threshold associated with the array values, to compare the array values with the at least one threshold, and to determine the interfering signal exists in response to at least the selected number of array values exceeding the at least one threshold.

18. The system of claim 17, wherein array values comprise a selected one of slope values, higher order derivative values, time sample absolute values, and power values associated with the time samples.

19. The system of claim 17, wherein the at least one threshold includes:

a first threshold related to a maximum expected array value; and

a second threshold related to a mean of the array values, wherein the interference detector is to compare the array values with at least one of the first threshold and the second threshold.

20. The system of claim 19, wherein the interference detector includes a threshold processor to detect that the interfering signal exists if at least a selected number of array values exceed at least one of the first threshold and the second threshold.

21. The system of claim 17, wherein the interference extent processor includes a limit processor to identify a lower array sample limit associated with a selected one of the selected number of array values exceeding the at least one threshold, to identify an upper array sample limit associated with another selected one of the selected number of array values exceeding the at least one threshold, to select a first sample guard band value, to select a second sample guard band value, to subtract the first sample guard band value from the lower array sample limit to provide an interfering signal lower array sample extent, to add the second sample guard band value to the upper array sample limit to provide an interfering signal upper array sample extent, and to identify at least one of an interfering signal lower time sample extent and an interfering signal upper time sample extent in accordance with the interfering signal lower array sample extent and the interfering signal upper array sample extent, respectively.

22. The system of claim 21, wherein the interference removal processor includes a selection processor to select a group of contiguous time samples excluding time samples between the interfering signal lower time sample extent and the interfering signal upper time sample extent.

23. The system of claim 21, wherein the interference removal processor includes a weighting processor to generate a weighting function in accordance with the interfering signal lower time sample extent and the interfering signal upper time sample extent and to apply the weighting function to the time samples.