Structure-based adaptive radar processing for joint interference cancellation and signal estimation
The present application provides techniques for reducing noise in sensor-based systems, such as radar systems. In particular, techniques referred to background supplemental cancellation (BaSC) and background supplemental loading (BaSL) are disclosed and facilitate improved detection of moving targets in certain types of radar systems, such as radar systems based on Reiterative minimum-mean square error (RMMSE) estimation formulations. The BaSC technique may utilize a hard cancellation, where clutter cancellation is performed prior to estimation, while the BaSL technique may utilize a “soft” cancellation technique whereby clutter cancellation is performed jointly with estimation. The clutter cancellation provided via the BaSC and BaSL techniques improves the accuracy of the radar system with respect to performing target detection.
1 . A method for processing radar signals, the method comprising:
transmitting, by a radar system, a radar waveform;
receiving, by the radar system, a radar waveform return corresponding to the transmitted radar waveform;
separating, by the radar system, the radar waveform return into a first component comprising clutter associated with stationary signal components and a second component comprising remaining radar waveform return associated with one or more moving targets;
generating, by the radar system, a filter bank based on the separated first component and the second component, wherein the filter bank is a reiterative minimum-mean square error (RMMSE) based adaptive filter bank;
processing, by the radar system, the radar waveform return based on the filter bank, wherein the processing comprises cancelling clutter based on the first component and performing spectral estimation of the radar waveform return; and
outputting, by the radar system, information derived from the radar waveform return based on the processing, the information indicating detection of the one or more moving targets, wherein cancelling clutter and performing spectral estimation comprises:
cancelling clutter associated with the stationary signal components prior to performing spectral estimation of the remaining radar waveform return associated with the one or more moving targets when the one or more moving targets have a first speed; and
jointly cancelling clutter associated with the stationary signal components and performing spectral estimation of the radar waveform return associated with the one or more moving targets when the one or more moving targets have a second speed less than the first speed.
2 . The method of claim 1 , wherein the remainder of the corresponding radar waveform return excludes noise.
3 . The method of claim 1 , wherein the clutter is cancelled by projecting the first component onto an orthogonal complement of a clutter subspace.
4 . The method of claim 3 , further comprising generating a cancellation matrix based on the first component, wherein projecting the first component onto the orthogonal complement of the clutter subspace comprises applying the cancellation matrix to a covariance matrix generated based on the radar waveform return.
5 . The method of claim 1 , wherein the clutter component is incorporated into the filter bank.
6 . The method of claim 1 , comprising updating the filter bank based on subsequent iterations of radar waveform returns, wherein the clutter is canceled based on the subsequent iterations of the radar waveform returns.
7 . A system for processing radar signals, the system comprising:
a memory;
a receiver configured to receive radar signals;
a transmitter configured to transmit radar signals;
one or more processors communicatively coupled to the memory, the transmitter, and the receiver, the one or more processors configured to:
generate radar waveforms for transmission by the transmitter;
process radar waveform returns corresponding to the transmitted radar waveforms, the radar waveform returns received by the receiver, the processing comprising:
separate the radar waveform returns into a first component comprising clutter associated with stationary signal components and a second component comprising remaining radar waveform return associated with one or more moving targets;
generate, for each radar waveform return, a filter bank based on the separated first component and the second component, wherein the filter bank is a reiterative minimum-mean square error (RMMSE) based adaptive filter bank;
cancel clutter based on the first component; and
perform spectral estimation of the radar waveform returns; and
output, by the system, information derived from the radar waveform return based on the processing, the information indicating detection of the one or more moving targets, wherein to cancel clutter and perform spectral estimation comprises:
cancel clutter associated with the stationary signal components prior to performing spectral estimation of the remaining radar waveform return associated with the one or more moving targets when the one or more moving targets have a first speed; and
jointly cancel clutter associated with the stationary signal components and perform spectral estimation of the radar waveform return associated with the one or more moving targets have a second speed less than the first speed.
8 . The system of claim 7 , wherein the remainder of the corresponding radar waveform return excludes noise.
9 . The system of claim 7 , wherein the clutter is cancelled by projecting the first component onto an orthogonal complement of a clutter subspace.
10 . The system of claim 9 , the one or more processors configured to generate a cancellation matrix based on the first component, wherein the one or more processors project the first component onto the orthogonal complement of the clutter subspace by applying the cancellation matrix to a covariance matrix generated based on the radar waveform return.
11 . The system of claim 7 , wherein the clutter component is incorporated into the filter bank.
12 . The system of claim 7 , the one or more processors configured to update the filter bank based on subsequent iterations of radar waveform returns, wherein the clutter is canceled based on the subsequent iterations of the radar waveform returns.