Multi-antenna joint optimization clutter suppression method based on fractional time delay estimation

Abstract

The present invention relates to a multi-antenna joint optimization clutter suppression method based on fractional time delay estimation. A receiving end monitoring channel receives a signal by using a uniform linear array, and a signal array model is established; the self-correlation matrix of an array model matrix is subjected to feature decomposition, a MUSIC spectrum is constructed, and the time delay estimation of a direct wave and a multipath clutter is obtained; the time delay signal after time delay is subjected to SINC function interpolation, and a corresponding clutter matrix is constructed; through constructing a cost function, an optimal time-domain weighting matrix WT_opt is obtained; the output of the array is weighted by using a least squares-constant modulus algorithm, a spatial weighting vector ws is solved, and the signal combination and output are carried out. According to the method, the time domain and spatial domain information of the signal are fully dug, the correlation of the signals in different array elements is monitored by using a receiving end, through the least squares-constant modulus algorithm, the noise and residual clutter outside a target echo coming direction are subjected to attenuation, the clutter rejection ratio of the output signal is raised, and the detection performance of a weak object can be improved at the same time.

Description

technical field [0001] The invention relates to the field of clutter suppression, in particular to a multi-antenna joint optimization clutter suppression method based on fractional time delay estimation. Background technique [0002] Passive radar uses an external non-cooperative radiation source as a signal source to detect and locate the detection target. Because it does not emit electromagnetic waves, it has good concealment and anti-reconnaissance performance; at the same time, it does not need emitting equipment, which saves manufacturing costs. In view of the above advantages, the research of passive radar system has been widely concerned by scholars at home and abroad in recent years. The external radiation sources used generally include FM broadcast signals, mobile communication signals, TV broadcast signals and satellite signals. Generally, there are two channels at the receiving end of the passive radar, the monitoring channel and the reference channel. Since th...

AI Technical Summary

Problems solved by technology

The method of adaptive interference cancellation is to use the correlation between the clutter signal in the echo channel and the direct wave signal in the reference channel, and through an adaptive method, the weighted reference signal and the mixed clutter signal are approximated, and finally To achieve the purpose of clutter suppression, this kind of algorithm has the problem of convergence speed, and the clutter suppression performance is general; the method of extended cancellation is actually to project the monitoring channel signal containing the target echo to the orthogonal complement of the clutter subspace Space, so as to effectively suppress clutter, this type of algorithm has no convergence problem, and the suppression performance is better, but the computational complexity is high

However, whether it is adaptive beamforming or interference cancellation, most of these methods are carried out in a single domain, and the information of the signal in multiple domains is not fully exploited, so the improvement of clutter suppression performance is limited.

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