Radar-based target tracker

1 . A method comprising:

for each frame of a plurality of frames over time, obtaining a combined image by combining a plurality of range-Doppler images each corresponding to a respective receive antenna of a millimeter-wave radar system, wherein the range-Doppler images are representative of a scene;

for each range and Doppler bin in the combined images for the frames over time, accumulating values each associated to a given frame and indicative of whether or not a detection has occurred in the corresponding range and Doppler bin in the combined image of the given frame;

for each range and Doppler bin in the combined images, determining a moving average based on the values accumulated over multiple frames of the plurality of frames for a corresponding range and Doppler bin;

filtering periodically moving objects in the scene in real time, filtering comprising, for a current frame, identifying range and Doppler bins in which repeated detection has occurred over past frames based on the moving averages, and generating an updated combined image for the current frame by suppressing the identified range and Doppler bins; and

detecting motion in the updated combined image, wherein the motion is detected using motion data from range and Doppler bins in the updated combined image that have moving averages below a detection threshold.

2 . The method of claim 1 further comprising:

obtaining the plurality of range-Doppler images using a constant false alarm rate algorithm.

3 . The method of claim 2 further comprising:

receiving a digitized radar signal from an analog-to-digital converter, the analog-to-digital converter coupled to the receiving antennas,

calculating range fast Fourier transform (FFT) data by performing a range fast Fourier transform on the digitized radar signal for a chirp; and

calculating the range-Doppler images by performing a Doppler FFT on the range fast Fourier transform data along multiple chirps.

4 . The method of claim 3 , further comprising obtaining moving target indicator data by applying moving target indicator filtering to raw digital data from the analog-to-digital converter before performing the range FFT on the digitized radar signal, wherein the moving target indicator filtering removes static targets from the digitized radar signal.

5 . The method of claim 1 , wherein suppressing the identified range and Doppler bins comprises setting values of the identified range and Doppler bins to zero.

6 . The method of claim 1 , wherein suppressing each identified range and Doppler bin comprises zeroing values of the combined image for each identified range and Doppler bin.

7 . The method of claim 1 , wherein identifying the range and Doppler bins in which repeated detection has occurred over past frames based on the moving averages comprises comparing the moving average for each corresponding range and Doppler bin to a threshold, wherein the suppressed range and Doppler bins correspond to bins whose moving average exceeds the threshold.

8 . A method comprising:

determining whether motion is detected on a per-bin basis for a sequence of range-Doppler images generated by a millimeter-wave radar sensor, wherein the range-Doppler images are representative of a scene;

summing a number of determined motion detections on a per-bin basis for a first number of range-Doppler images of the sequence of range-Doppler images to produce summed motion detections;

filtering periodically moving objects in the scene in real time comprising:

determining per-bin moving averages for the summed motion detections,

comparing each per-bin moving average of the per-bin moving averages to a threshold, and

suppressing bins in a range-Doppler image of the sequence of range-Doppler images to produce a modified range-Doppler image, the suppressed bins corresponding to bins in the range-Doppler image whose moving average exceeds the threshold; and

detecting motion based on the modified range-Doppler image, wherein the motion is detected using motion data from range and Doppler bins in the modified range-Doppler image that have moving averages below the threshold.

9 . The method of claim 8 , wherein determining whether motion is detected comprises applying a constant false alarm rate algorithm to the sequence of range-Doppler images.

10 . The method of claim 8 , wherein suppressing the bins in the range-Doppler image comprises setting values of the suppressed bins in the modified range-Doppler image to zero.

11 . The method of claim 10 , wherein each range-Doppler image of the sequence of range-Doppler images comprises a combined range-Doppler image based on data received from a plurality of antennas.

12 . The method of claim 8 , further comprising:

receiving a digitized radar signal from the millimeter-wave radar sensor;

performing a range fast Fourier transform (FFT) on the digitized radar signal to produce range FFT data; and

performing a Doppler FFT on the range FFT data to produce the range-Doppler image of the sequence of range-Doppler images.

13 . The method of claim 12 , further comprising applying moving target indicator filtering to the received digitized radar signal before performing the range FFT.

14 . The method of claim 12 , further comprising digitizing a radar signal produced by the millimeter-wave radar sensor using an analog-to-digital converter to produce the digitized radar signal.

15 . A system comprising:

a radar signal processor configured to be coupled to a millimeter-wave radar sensor, the radar signal processor configured to:

receive a radar signal from the millimeter-wave radar sensor,

generate a sequence of range-Doppler images based on the received radar signal, wherein the range-Doppler images are representative of a scene;

determine whether motion is detected on a per-bin basis for the sequence of range-Doppler images,

sum a number of determined motion detections on a per-bin basis for a first number of range-Doppler images of the sequence of range-Doppler images to produce summed motion detections,

filter periodically moving objects in the scene in real time by:

determining per-bin moving averages for the summed motion detections,

comparing each per-bin moving average of the per-bin moving averages to a threshold, and

suppressing bins in a range-Doppler image of the sequence of range-Doppler images to produce a modified range-Doppler image, the suppressed bins corresponding to bins in the range-Doppler image whose moving average exceeds the threshold; and

detect motion based on the modified range-Doppler image, wherein the motion is detected using motion data from range and Doppler bins in the modified range-Doppler image that have moving averages below the threshold.

16 . The system of claim 15 , wherein the radar signal processor is configured to determine whether motion is detected by applying a constant false alarm rate algorithm to the sequence of range-Doppler images.

17 . The system of claim 16 , wherein the radar signal processor is configured to suppress the bins in the range-Doppler image by setting values of the suppressed bins in the modified range-Doppler image to zero.

18 . The system of claim 17 , wherein each range-Doppler image of the sequence of range-Doppler images comprises a combined range-Doppler image based on data received from a plurality of antennas of the millimeter-wave radar sensor.

19 . The system of claim 15 , further comprising the millimeter-wave radar sensor.

20 . The system of claim 14 , wherein:

the radar signal processor is further configured to:

perform a range fast Fourier transform (FFT) on the radar signal to produce range FFT data; and

perform a Doppler FFT on the range FFT data to produce the range-Doppler image of the sequence of range-Doppler images.