Radar interference mitigation

Patent metadata

Field	Value
Publication number	US-9952312-B2
Application number	US-201514791751-A
Country	US
Kind code	B2
Filing date	Jul 6, 2015
Priority date	Jul 6, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

Various implementations described herein are directed to a method for mitigating radar interference. The method may include receiving time domain signals from a radar device and transforming the time domain signals to time-frequency domain signals. The method may include comparing each time-frequency domain signal with one or more surrounding time-frequency domain signals to determine which of the time-frequency domain signals have interference. The method may include repairing the time-frequency domain signals having interference.

First claim

What is claimed is:

1. A method comprising:
receiving time domain signals from a radar device, wherein each of the time domain signals is obtained during a sweep of the radar device;
transforming, using a processor, the time domain signals to time-frequency domain signals;
comparing, using the processor, each time-frequency domain signal with one or more previous or subsequent time-frequency domain signals to determine which of the time-frequency domain signals have interference;
repairing, using the processor, the time-frequency domain signals having interference by:
determining a median magnitude of cell values for multiple sweeps of the radar device,
determining an average vector difference between the multiple sweeps, and
replacing a magnitude for each sweep having interference with an interpolated magnitude based on the median magnitude of cell values and the average vector difference; and

detecting, using the processor, a target using the repaired time-frequency domain signals.

2. The method of claim 1 , wherein the radar device comprises a frequency-modulated continuous-wave (FMCW) radar or a pulse compression radar.

3. The method of claim 1 , wherein the time domain signals comprise radar related waveforms in time domain, and wherein the time-frequency domain signals comprise radar related waveforms in time-frequency domain.

4. The method of claim 1 , wherein transforming the time domain signals to time-frequency domain signals involves using a short-time Fourier transform to generate the time-frequency domain signals from the time domain signals.

5. The method of claim 1 , further comprising storing the time-frequency domain signals for multiple sweeps of the radar device, wherein each sweep comprises a rotation interval of the radar device over a period of time.

6. The method of claim 1 , wherein determining which of the time-frequency domain signals have interference, comprises:
storing the time-frequency domain signals for multiple sweeps of the radar device,
determining a median magnitude of cell values for the multiple sweeps, for each sweep, if a magnitude of cell values of the sweep is greater than the median magnitude of cell values for the multiple sweeps plus a threshold, then the sweep is identified as having interference, and
for each sweep, if the magnitude of cell values of the sweep is less than the median magnitude of cell values for the multiple sweeps, then the sweep is identified as not having interference.

7. The method of claim 1 , wherein determining which of the time-frequency domain signals have interference, comprises:
storing the time-frequency domain signals for multiple sweeps of the radar device,
determining a mean magnitude of cell values for the multiple sweeps,
for each sweep, if a magnitude of cell values of the sweep is greater than the mean magnitude of cell values for the multiple sweeps plus a threshold, then the sweep is identified as having interference, and
for each sweep, if the magnitude of cell values of the sweep is less than the mean magnitude for the multiple sweeps, then the sweep is identified as not having interference.

8. The method of claim 1 , wherein determining which of the time-frequency domain signals have interference, comprises:
storing the time-frequency domain signals for multiple sweeps of the radar device,
determining a lower bounded magnitude of cell values for the multiple sweeps,
for each sweep, if a magnitude of cell values of the sweep is greater than the lower bounded magnitude plus a threshold, then the sweep is identified as having interference, and
for each sweep, if the magnitude of cell values of the sweep is less than the lower bounded magnitude, then the sweep is identified as not having interference.

9. The method of claim 1 , further comprising transforming each of the time-frequency domain signals into time domain signals.

10. A non-transitory computer-readable medium having stored thereon a plurality of computer-executable instructions which, when executed by a computer, cause the computer to:
receive time domain waveforms for multiple sweeps of a radar device, wherein each of the time domain waveforms is obtained during a sweep of the radar device;
transform the time domain waveforms for the multiple sweeps to time-frequency domain waveforms for the multiple sweeps;
determine which of the time-frequency domain waveforms have interference by comparing a magnitude of cell values of each time-frequency domain waveform for each sweep to a first pre-determined magnitude calculated based on magnitudes of cell values of previous or subsequent time-frequency domain waveforms of previous or subsequent sweeps; and
repairing, using the processor, the time-frequency domain signals having interference by:
determining a median magnitude of cell values for multiple sweeps of the radar device,
determining an average vector difference between the multiple sweeps, and
replacing a magnitude for each sweep having interference with an interpolated magnitude based on the median magnitude of cell values and the average vector difference.

11. The non-transitory computer-readable medium of claim 10 , further comprising instructions that cause the computer to:
store the time-frequency domain waveforms for the multiple sweeps; and
transform each of the time-frequency domain waveforms into time domain waveforms.

12. The non-transitory computer-readable medium of claim 10 , wherein the first pre-determined magnitude comprises a median magnitude of cell values of the multiple sweeps, a mean magnitude of cell values of the multiple sweeps, or a lower bounded magnitude of cell values of the multiple sweeps.

13. The non-transitory computer-readable medium of claim 10 , wherein the second pre-determined magnitude comprises a zero magnitude, a median magnitude of cell values of the multiple sweeps, or an interpolated magnitude based on the median magnitude of cell values of the multiple sweeps and an average vector difference between the multiple sweeps.

14. A method comprising:
receiving signals in time domain for multiple sweeps of a radar device, wherein each of the time domain signals is obtained during a sweep of the radar device;
performing, using a processor, a time-frequency transform on the received signals;
examining, using the processor, each signal for each sweep in comparison with previous or subsequent signals for previous or subsequent sweeps to determine which of the signals have interference;
repairing, using the processor, the signals in time-frequency domain having interference by:
determining a median magnitude of cell values for multiple sweeps of the radar device,
determining an average vector difference between the multiple sweeps, and
replacing a magnitude for each sweep having interference with an interpolated magnitude based on the median magnitude of cell values and the average vector difference;

performing, using the processor, a reverse time-frequency transform on each of the signals in time-frequency domain including the repaired signals in time-frequency domain, thereby providing repaired time domain signals, and
detecting, using a processor, a target based on the repaired time domain signals.

15. The method of claim 14 , further comprising storing the time-frequency domain signals for the multiple sweeps of the radar device, wherein determining which of the time-frequency domain signals have interference comprises:
comparing a magnitude of cell values of each time-frequency domain signal for each sweep to a first pre-determined magnitude calculated based on magnitudes of cell valu

Assignees

• Navico Holding As

Inventors

• Corbett Andrew

Classifications

• G01S7/354

  Extracting wanted echo-signals (Doppler systems G01S13/50) · CPC title

• G01S7/023 Primary

  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 title