Radar Interference Suppression Using STFT Spectrogram Thresholding
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Solution Overview
Problem
Radar communications are susceptible to interference from other sources, leading to undesirably low signal-to-noise ratio (SNR) and challenges in accurately processing received radar signal reflections, particularly when interfering radar systems have moderately to highly correlated chirps.
Innovation Solution
A radar system processes radar reflections by converting them into a time-frequency domain using Short Time Fourier Transform (STFT), determines suppression thresholds based on MIN-of-MAX values, and generates an interference-suppressed spectrogram by removing or attenuating interference components, followed by inverse STFT to produce interference-suppressed samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional interference mitigation approaches are used, then interference suppression is attempted, but signal-to-noise ratio deteriorates due to sample loss
Solution Approach 1:
The patent transforms the radar signal processing from the time domain to the time-frequency domain using STFT (Short-Time Fourier Transform). This dimensional change allows interference components to be visually identified and selectively removed from the spectrogram while preserving signal components, thereby suppressing interference without the sample loss that plagues conventional time-domain mitigation approaches.
Solution Approach 2:
The patent applies local quality by performing thresholding operations on individual frequency bins and time frames of the spectrogram. Each cell in the spectrogram is evaluated independently against a threshold, allowing selective removal of interference in specific time-frequency regions while preserving signal components in other regions. This localized approach prevents the global sample loss that occurs in conventional methods.
2Adaptability or versatility
If radar communications operate in environments with correlated interfering chirps, then communication functionality is maintained, but processing accuracy deteriorates
Solution Approach 1:
The patent addresses correlated interference by moving to the time-frequency domain where correlated chirps manifest as distinct patterns in the spectrogram. This dimensional transformation enables the differentiation between signal and interference even when they are correlated in the time domain, thereby maintaining processing accuracy while preserving communication functionality.
Solution Approach 2:
The patent uses the visual representation of the spectrogram where different frequency components are displayed as distinct 'colors' or intensity levels across time. This allows correlated interfering chirps to be visually distinguished from legitimate signal components based on their unique time-frequency signatures, enabling accurate identification and selective suppression of interference while preserving signal processing accuracy.
Data Source
AI summary
Aspects of the present disclosure relate to a radar system and method of operation thereof, whereby a spectrogram is generated by processing circuitry of a radar system by converting samples, of reflections of transmitted radar signals reflected by an object in an environment of the radar system, into a time-frequency domain, determining at least one threshold based on at least one MIN-of-MAX value for magnitudes of a frequency signal of the spectrogram, generating an interference-suppressed spectrogram by removing or attenuating interference components from the spectrogram based on the at least one threshold, and generating interference-suppressed samples based on the interference-suppressed spectrogram.