Background noise spectrum fluctuation characteristic-based wideband array signal processing method

Abstract

The invention relates to a background noise spectrum fluctuation characteristic-based wideband array signal processing method. The processing method includes the following steps that: a frequency domain covariance matrix can be estimated accurately through the accumulation of a plurality of times of snap-shotting, and the frequency domain covariance matrix is also the foundation for obtaining exact solutions of a diagonal load reduction coefficient and a post-positioned weighted coefficient at follow-up stages; eigen-decomposition is performed on the frequency domain covariance matrix, so that the diagonal load reduction coefficient can be solved, and the main diagonal element of the frequency domain covariance matrix is multiplied by the load reduction coefficient, so that a new frequency domain covariance matrix can be obtained; MVDR beam forming is performed on the frequency domain covariance matrix which has been subjected to load reduction, so that the space energy spectra of each frequency point can be obtained; and finally, weighted summation is performed on the space energy spectra of each frequency point through using an optimal band weighted coefficient, so that a final spatial energy spectrum can be obtained. With the background noise spectrum fluctuation characteristic-based wideband array signal processing method of the invention adopted, detection performance for a weak target can be improved, and multi-target distinguishing performance can be improved. Compared with a conventional beam forming device and an MVDR beam forming device, the background noise spectrum fluctuation characteristic-based wideband array signal processing method has better detection performance.

Description

technical field [0001] The invention belongs to the technical field of underwater acoustic passive broadband array signal processing, and in particular relates to a broadband array signal processing method based on background noise spectrum fluctuation characteristics. Background technique [0002] Compared with narrowband signal processing, broadband array signal processing can obtain more target and environmental signals, especially in the environment of underwater acoustic signal processing, where the environmental noise has the characteristics of high noise level, obvious fluctuation of spectrum amplitude and complex spectrum structure, etc. Acoustic broadband array signal processing has become a research hotspot in recent years. In the absence of any array noise and prior information of the target signal, only the equal-weighted summation of the spatial energy spectra of each narrowband MVDR cannot achieve the best processing effect. Therefore, how to suppress marine e...

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Problems solved by technology

However, if the input signal-to-noise ratio is proportional to the frequency below a certain critical frequency, this method will sacrifice certain multi-target resolution performance

However, under the condition of low SNR, adaptive beamforming itself cannot produce ideal nulls in the interference azimuth, so that the interference leaks to the current scanning beam, and correspondingly affects its multi-target resolution performance.

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