Sidelobe Subtraction for Automotive Radar Target Detection
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Solution Overview
Problem
Existing radar signal processing methods for autonomous vehicles suffer from sidelobe artifacts generated by FFT operations, which can bury weaker targets behind stronger ones, leading to performance degradation in target detection and resolution.
Innovation Solution
A method that estimates and subtracts sidelobes from the FFT response of identified targets, iteratively improving sidelobe suppression to enhance the detection of weaker targets, achieving sidelobe suppression by 9 dB or more compared to the original level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FFT processing is used to extract target information, then range, Doppler velocity and angle information can be obtained, but sidelobe artifacts are generated that bury weak targets
Solution Approach 1:
The patent estimates the sidelobe components generated by FFT processing and subtracts them from the original signal. By converting the harmful sidelobe artifacts into estimable and removable components, the method recovers weak targets that were previously buried, transforming the harmful interference into a solvable problem through mathematical estimation and subtraction
Solution Approach 2:
The patent extracts and removes the sidelobe components from the FFT processed signal. By separating the sidelobe artifacts from the main signal and subtracting them, the method isolates and eliminates the harmful components while preserving the useful target information, thereby resolving the contradiction between obtaining target information and avoiding sidelobe interference
2Object-generated harmful factors
If taper window is used to suppress sidelobes, then sidelobe levels are reduced, but mainlobe width broadens and resolution decreases
Solution Approach 1:
Instead of using taper windows that trade resolution for sidelobe suppression, the patent estimates the sidelobe components mathematically and subtracts them directly. This approach suppresses sidelobes to the desired level while preserving the original mainlobe shape and resolution, converting the harmful sidelobes into removable artifacts without sacrificing measurement precision
Solution Approach 2:
The patent changes the approach from modifying the signal window function to directly manipulating the sidelobe parameters through estimation and subtraction. By changing from a windowing approach to a parameter-based subtraction method, the system achieves sidelobe suppression while maintaining the original resolution characteristics of the FFT bins
3Reliability
If sidelobe suppression is applied to improve target detection, then weak targets become detectable, but signal processing complexity increases
Solution Approach 1:
The patent extracts only the necessary sidelobe components for suppression rather than reprocessing the entire signal through complex algorithms. By identifying and removing only the sidelobe portions that interfere with target detection, the method improves reliability while keeping the processing complexity manageable through targeted rather than comprehensive processing
Data Source
AI summary
A method is disclosed for suppressing sidelobes due to artifacts introduced by FFT operations during automotive radar signal processing. Sidelobes of a stronger target from the FFT operations may bury the response from a weaker target when there are multiple targets. The method estimates the sidelobes of an identified target from a measured FFT response and subtracts the estimated sidelobes from the measured FFT response. The identified target may be the strongest target from the measured FFT response. The method estimates the sidelobes to suppress the sidelobes with respect to the peak signal of the identified target. After the estimated sidelobes of the identified target are removed, the updated FFT response may reveal other targets that had been buried. The method may identify additional targets to estimate their sidelobes and may iteratively remove the estimated sidelobes of additional targets from the FFT until a desired sidelobe residual level is achieved.