Multistage sub-array focusing MVDR wave beam forming method

Abstract

The invention relates to a multistage sub-array focusing MVDR wave beam forming method. According to the multistage sub-array focusing MVDR wave beam forming method, a common rapid frequency-domain broadband wave beam forming algorithm and a sub-array focusing MVDR algorithm are combined, a target orientation is firstly and roughly measured through the rapid frequency-domain broadband wave beam forming algorithm, then sub-arrays are divided, finally the target orientation is accurately measured through the sub-array focusing MVDR algorithm, and rapid and high-accuracy wave beam forming is achieved. The multistage sub-array focusing MVDR wave beam forming method includes the steps of 1, firstly completing rapid frequency-domain broadband wave beam forming on data received by a linear array sonar device through one-time time-domain FFT and airspace phase compensation, and completing initial estimation of the target orientation; 2, then carrying out peak detection on a common wave beam forming curve, after a target is found, carrying out sub-array dividing on a frequency-domain array signal, carrying out sub-array focusing MVDR wave beam forming on the orientation nearby the target, carrying out secondary orientation detection, and obtaining the more accurate target orientation. By means of the multistage sub-array focusing MVDR wave beam forming method, the performance of a whole sonar positioning system is improved, and meanwhile the requirements for the real-time performance, the high resolution and the tolerance are met.

Description

technical field [0001] The invention belongs to the field of sonar digital signal processing, in particular to a hierarchical sub-array focusing MVDR (Minimum Variance Distortionless Response, minimum variance distortion-free response algorithm) beamforming method, which can be applied to various line array sonar systems to achieve fast and high-precision Beamforming. Background technique [0002] Limited by the Rayleigh limit, for a small-aperture array, it is difficult to distinguish two or more targets that are close in azimuth by using the traditional wave of arrival estimation algorithm. The MVDR algorithm proposed by Capon in the document "High-resolution frequency-wavenumber spectrum analysis" in 1969 is a wave of arrival estimation algorithm with high-resolution performance in theory, but the operation process will involve high-dimensional matrix inversion, and the complexity is very high. High, and the algorithm requires a relatively high signal-to-noise ratio, and...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the limited resolution faced by conventional beamforming, the inability to achieve high-precision direction finding of targets, and the problems of high computational complexity and poor stability faced by adaptive high-resolution beamforming methods such as MVDR, thus proposing A hierarchical sub-array focused MVDR beamforming method to simultaneously meet the requirements of sonar system beamforming in terms of real-time performance, high-resolution capability and tolerance

[0005] The present invention considers the huge advantages of the ordinary beam frequency-domain broadband beamforming method in terms of real-time and tolerance. In order to solve the problem of high-precision passive direction finding of the small-aperture horizontal array, the present invention proposes a hierarchical beamforming idea: Combining ordinary fast frequency-domain broadband beamforming with sub-array focusing MVDR algorithm, the fast frequency-domain broadband beamforming algorithm completes the rough measurement of the target azimuth, and then the sub-array focusing MVDR algorithm completes the precise measurement of the target azimuth, thereby improving the overall acoustics The performance of the nano-orientation system, while meeting the needs of real-time, high resolution and tolerance

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