CN-122017750-A - Clutter interference suppression method based on sub-banding processing

Abstract

The invention discloses an interference suppression method, in particular to a clutter suppression method based on subband processing, which comprises the following steps of S1 receiving a monitoring signal containing target reflection echo, direct wave and clutter and a relatively pure direct wave reference signal, S2 converting the monitoring signal and the reference signal from time domains to frequency domains respectively, S3 uniformly dividing the converted frequency domain monitoring signal and the converted frequency domain reference signal into a plurality of subbands respectively, S4 carrying out clutter suppression processing on the subband monitoring signal based on the subband reference signal in each subband so as to remove clutter components related to the reference signal and keep a moving target signal, S5 synthesizing all the subband processed signals according to a frequency band sequence to obtain a monitoring signal after full frequency band clutter suppression, and S6 carrying out phase correlation processing on the synthesized monitoring signal and the reference signal to realize target detection and parameter estimation.

Inventors

• WANG HAIBO
• HE LANMAO

Assignees

• 上海银帆信息科技有限公司

Dates

Publication Date

20260512

Application Date

20260401

Claims (5)

1. 1. A clutter interference suppression method based on sub-banding processing is characterized by comprising the following steps: s1, receiving a monitoring signal containing target reflection echoes, direct waves and clutter and a relatively pure direct wave reference signal; S2, respectively converting the monitoring signal and the reference signal from a time domain to a frequency domain; S3, uniformly dividing the converted frequency domain monitoring signal and the frequency domain reference signal into a plurality of sub-bands respectively; S4, in each sub-band, carrying out clutter suppression processing on the sub-band monitoring signals based on the sub-band reference signals so as to remove clutter components related to the reference signals and keep a moving target signal; S5, synthesizing the signals processed by all the sub-bands according to the frequency band sequence to obtain a monitoring signal after full-band clutter suppression; s6, performing coherent processing on the synthesized monitoring signal and the reference signal to realize target detection and parameter estimation.
2. 2. The clutter suppression method based on the subband processing according to claim 1, wherein in step S4, the clutter suppression processing in each subband specifically includes: s41, constructing a clutter subspace based on a reference signal of a current subband; s42, estimating the projection weight of the subband monitoring signal on the clutter subspace; S43, subtracting clutter estimation components formed by the reference signals and the projection weights from the subband monitoring signals.
3. 3. The clutter interference suppression method based on the subband processing according to claim 2, wherein the clutter subspace is composed of reference signal spectrum vectors of the current subband.
4. 4. The clutter suppression method based on the subband processing according to claim 1, wherein in step S3, the number and the width of the subband division are dynamically adjusted according to the total bandwidth of the original signal, the system distance resolution requirement or the environmental clutter intensity.
5. 5. The method of claim 1, further comprising performing an amplitude phase calibration on the subband reference signals to match channel characteristics of the subband monitoring signals prior to performing step S4.

Description

Clutter interference suppression method based on sub-banding processing Technical Field The invention relates to the technical field of signal processing, in particular to a clutter interference suppression method based on subband processing. Background The external radiation source radar utilizes the non-cooperative irradiation source signals of third parties such as broadcasting, communication and the like to detect the target, and has the advantages of good concealment, low cost, rich frequency spectrum resources and the like. However, in real-time signal processing, how to effectively suppress strong clutter interference from direct waves, multipath reflections and environmental stationary objects is always a core technical problem that restricts the detection performance. The existence of strong clutter can seriously mask weak moving target echoes, so that the target detection probability is reduced and the false alarm rate is increased. In order to solve the clutter suppression problem, the prior art mainly expands around two methods, namely, a method based on spatial filtering and forming a beam zero point through an array antenna to align the clutter direction, but the method has high requirement on array calibration and is difficult to cope with clutter with wide distribution range, and a method based on signal processing of time domain/frequency domain, such as an extended cancellation algorithm and an improved algorithm thereof. The algorithm is used for estimating and canceling clutter subspace in a signal domain by constructing a correlation matrix between a reference signal and a monitoring signal, and is the mainstream of the current engineering application. However, as radar signal bandwidth increases and clutter scenes in the real world become more complex, conventional ECA-like approaches face significant challenges. First, the broadband signal means a high distance resolution capability, and also spreads clutter in the distance dimension, with a significant increase in freedom. In order to accurately estimate and suppress such high-degree-of-freedom clutter, a high-dimensional clutter subspace needs to be constructed and complex matrix operation is performed, so that the calculation amount and the storage requirement of an algorithm are increased sharply, and real-time processing requirements are difficult to meet. Secondly, in the dense clutter background, the suppression performance of the traditional method may be reduced due to inaccurate spatial estimation, and the residual clutter still affects target detection. Therefore, a robust clutter suppression technique that can significantly reduce the computational complexity while ensuring the clutter suppression depth and is suitable for wideband signals and complex clutter environments is needed. The present invention has been made in this context. Disclosure of Invention The invention aims to solve the problems in the prior art and provides a clutter interference suppression method based on subband processing so as to solve the existing technical problems. The technical scheme adopted for solving the technical problems is as follows: the invention provides a clutter interference suppression method based on sub-banding processing, which comprises the following steps: s1, receiving a monitoring signal containing target reflection echoes, direct waves and clutter and a relatively pure direct wave reference signal; S2, respectively converting the monitoring signal and the reference signal from a time domain to a frequency domain; S3, uniformly dividing the converted frequency domain monitoring signal and the frequency domain reference signal into a plurality of sub-bands respectively; S4, in each sub-band, carrying out clutter suppression processing on the sub-band monitoring signals based on the sub-band reference signals so as to remove clutter components related to the reference signals and keep a moving target signal; S5, synthesizing the signals processed by all the sub-bands according to the frequency band sequence to obtain a monitoring signal after full-band clutter suppression; s6, performing coherent processing on the synthesized monitoring signal and the reference signal to realize target detection and parameter estimation. Preferably, in step S4, the performing clutter suppression processing in each sub-band specifically includes: s41, constructing a clutter subspace based on a reference signal of a current subband; s42, estimating the projection weight of the subband monitoring signal on the clutter subspace; S43, subtracting clutter estimation components formed by the reference signals and the projection weights from the subband monitoring signals. Preferably, the clutter subspace is formed by reference signal spectrum vectors of the current subband. Preferably, in step S3, the number and width of sub-band divisions are dynamically adjusted according to the total bandwidth of the original signal, the system range resolution r