Method for echo direction estimation of sensor array and for multibeam echo depth sounding and bottom detection

Abstract

The invention discloses a method for echo direction estimation of a sensor array and for multibeam echo depth sounding and bottom detection. The method for echo direction estimation of the sensor array comprises the following steps: (1) scanning beams and detecting echoes of data received by the array to obtain a space region corresponding to the echo and select more than three desired angles; (2) acquiring the output beams of each sub-array or each virtual sub-array at each desire angle and obtaining the delay relationship between every two sub-arrays or every two virtual sub-arrays; and (3)estimating the direction of each echo by utilizing a high-resolution signal arrival direction angle estimation algorithm based on the output beams and the delay relationship which are obtained in thestep (2). The method disclosed in the invention is suitable for sensor arrays with irregular shapes, and can break up the restriction of the resolution by the array aperture so as to improve the bottom detection accuracy of edge beams of a multibeam echo detection system. By utilizing the method, the requirement for data while the high-resolution signal arrival direction angle estimation algorithm is conducted is lowered so as to facilitate the engineering application.

Description

technical field [0001] The invention belongs to the field of sensor array signal processing and sonar technology, and particularly relates to a high-resolution detection method for a multi-beam echo sounding system. Background technique [0002] A basic part of multi-beam echo sounding bottom detection processing is the azimuth estimation of echo signals. Usually, the multi-beam echo sounding system performs spatial filtering on the received echo signal through conventional beamforming, and then obtains the distance and direction of arrival estimation of the bottom echo through further bottom detection processing. Under the condition of a certain array aperture, the spatial resolution of conventional beamforming is limited, and the beamwidth of the actual system is usually 1.5° to 3°; for a linear array, the beamwidth of the edge deviates from the normal and transverse direction is larger, close to 6°. The underwater footprint corresponding to the beam expands with the incr...

AI Technical Summary

Problems solved by technology

[0003] When applying the high-resolution processing method in the multi-beam echo sounding system, the following aspects need to be considered: First, the received signal of the multi-beam echo sounding system is the bottom backscatter signal, which needs to meet the requirements of high-resolution processing. The algorithm has requirements for noise characteristics and signal-to-noise ratio; secondly, the transmitted signals of the multi-beam echo sounding system are usually high-frequency and narrow-band, and the number of sampling points in one echo pulse is small, and the continuous distribution of the seabed results in echo signal Non-stationarity in time limits the number of samples that can be used for high-resolution echo azimuth estimation; in addition, in order to improve resolution and coverage width, the receiving array of the system is usually a non-linear array. There is a high demand for applicability

Although the estimation performance of the MUSIC algorithm and related subspace fitting algorithms is good, it involves a large amount of calculation, poor real-time performance, and is very sensitive to the uncertainty of the environment and the error of the array itself.

In addition, with the rapid development of modern signal processing theories, theories such as time-frequency analysis and wavelet analysis are also widely used in underwater target orientation estimation, but these methods either have a large amount of calculation or are not stable enough to be used in Realized in practical application

[0005] In short, considering the particularity of the working environment of the multi-beam echo sounding system (continuously distributed source model, the complexity of channel propagation, the diversity of formations, etc.), the application of the above algorithm in the multi-beam echo sounding system It is still rare, and it is necessary to develop a new high-precision azimuth estimation method suitable for multi-beam echo sounding system settings and signal characteristics, so as to facilitate engineering implementation

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