Multi-dimensional domain joint SAR broadband interference suppression method based on low-rank matrix decomposition

Abstract

The invention provides a multi-dimensional domain joint SAR broadband interference suppression method based on low-rank matrix decomposition. Broadband interference signals exist in a plurality of pulses of current echo data. The short-time Fourier transform matrixes of the pulse echo signals are vectorized respectively; RPCA decomposition is performed to obtain a low-rank matrix and a sparse matrix; each row of the decomposed sparse matrix is rearranged into a short-time Fourier matrix form; the rearranged short-time Fourier matrix is subjected to inverse short-time Fourier transform, the reconstructed interference signal is subtracted from the original echo signal to realize broadband interference suppression, and data subjected to interference suppression is imaged by using an existingimaging algorithm to obtain a high-resolution image. According to the method, the problem of useful signal loss caused by time-frequency filtering is avoided, compared with a traditional method basedon energy characteristic difference, useful signal information can be effectively reserved while interference is suppressed, and the image quality after broadband interference suppression can be improved to a large extent.

Description

technical field [0001] The invention relates to the field of signals, in particular to a combined time-frequency-pulse multi-dimensional domain interference suppression method, which is suitable for broadband interference suppression with time-frequency aggregation characteristics in a time-frequency plane. Background technique [0002] Since Synthetic Aperture Radar (SAR) has the characteristics of all-day, all-weather work and wide-area surveillance, its application in battlefield reconnaissance and resource exploration has received more and more attention. In recent years, the rapid development of jamming technology poses a huge threat to SAR precise remote sensing technology. According to the bandwidth of the interference signal, the interference can be divided into narrow-band interference (Narrow-Band Interference, NBI) and wide-band interference (Wide-Band Interference, WBI). [0003] At present, narrowband interference suppression methods are relatively mature, such...

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Problems solved by technology

In order to overcome the existing problem of energy loss of useful signals based on short-time Fourier transform, the present invention transforms each pulse-echo data into the short-time Fourier transform domain. For useful signals, several adjacent pulses In the echo, the echo signal is constant or slowly changing, so it can be considered that the time-frequency distribution of the useful signal satisfies the low-rank characteristic in multiple pulses; and for the broadband interference signal, the interference signal transmits pulse repetition period In general, it will not be strictly consistent with the useful signal transmission cycle, which means that within the pulse repetition cycle of the useful signal, parameters such as the starting frequency, modulation frequency, modulation index, and initial phase will change relatively greatly. Within the pulse repetition period of , the interference signal does not have low-rank characteristics, as shown in 1

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