SAR time-varying narrow-band interference suppression method based on time-frequency spectrogram decomposition

Abstract

The invention discloses an SAR time-varying narrow-band interference suppression method based on time-frequency spectrogram decomposition. The method comprises the steps of obtaining back wave data; judging whether narrow-band interference exists in the back wave data or not, and if the interference exists, executing a next step; obtaining a composite signal time-frequency spectrogram according to column vectors of the back wave data with the narrow-band interference, conducting singular value decomposition, and obtaining a corresponding signal matrix to be separated; separating the signal matrix to be separated, and obtaining an interference signal matrix; utilizing interference signal components in the interference signal matrix to reconstruct an interference signal time-frequency spectrogram according to the least squares criterion, removing interference signals from the composite signal time-frequency spectrogram to obtain a useful signal time-frequency spectrogram, conducting the inverted short-time Fourier transform on the useful signal time-frequency spectrogram, and obtaining the column vectors of the back wave data after the interference is removed; judging whether traversal of all the column vectors of the back wave data is completed or not, and if the traversal is completed, obtaining the back wave data after the interference is removed. The SAR time-varying narrow-band interference suppression method based on the time-frequency spectrogram decomposition has the advantages of being less in calculation, higher in efficiency and free of data missing.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and in particular relates to a time-varying narrowband interference suppression method for SAR based on time-spectrogram decomposition in the radar signal processing technology. Background technique [0002] Narrowband jamming is one of the main jamming methods for Synthetic Aperture Radar (SAR) systems. The so-called narrow-band interference refers to a signal with a small ratio (eg, 1%) of the bandwidth of the interfering signal to the bandwidth of the signal transmitted by the synthetic aperture radar. Narrowband interference can be divided into two categories: non-human interference and human interference. Non-man-made interference mainly includes communication equipment, TV networks and other low-frequency band radiation equipment in the same frequency band as SAR; common man-made interference mainly includes strong pulse interference and frequency-guided "targeting" interference....

AI Technical Summary

Problems solved by technology

However, this method has the following disadvantages: it uses time smoothing to increase the observation channel, reduces the number of samples, shortens the length of the estimated interference signal, reduces the calculation accuracy of the independence criterion, and makes the separation of the interference signal incomplete, thus affecting the Effect of Separation Inhibition

This method decomposes the signal into a series of eigenmode functions, and fully retains the nonlinear and non-stationary characteristics of the signal itself while suppressing narrow-band interference. False signals will be decomposed, so that the time-frequency characteristics of the interference signal cannot be effectively described, resulting in incomplete separation of the interference signal

Images