Combined acoustic array for multi-beam synthetic aperture sonar

Abstract

The invention provides a combined acoustic array for a multi-beam synthetic aperture sonar. The combined acoustic array mainly comprises a long linear transmitting transducer, an azimuth direction receiving linear array and a distance direction receiving linear array, wherein the receiving linear arrays consist of a group of uniformly spaced sensors; the azimuth direction receiving linear array and the distance direction receiving linear array are vertical to each other; the long linear transmitting transducer is vertical to the distance direction receiving linear array; and the distance direction receiving linear array is used for forming multi-beams, forming beams at a plurality of angles by processing beam forming of echo signals thereof, and removing azimuth ambiguity caused by space undersampling by performing synthetic aperture treatment on the echo signal of each array element of the azimuth direction receiving array under the conditions of definite pulse transmitting frequency and the increasing navigation speed of a mother ship. The azimuth ambiguity caused by the space undersampling is removed by the azimuth direction receiving linear array so as to increase the surveying and mapping speed of the multi-beam synthetic aperture sonar; and the combined acoustic array has a simple process and low cost.

Description

technical field [0001] The invention relates to a combined acoustic array. Background technique [0002] Multi-beam bathymetric sonar is one of the most important equipment currently used for seabed topography mapping. It can achieve large-scale full-coverage measurement, and has the ability to quickly and accurately obtain underwater topography, find targets, and identify seabed types. The working principle of multi-beam sounding sonar is to use the acoustic base array to transmit and receive ultrasonic detection pulse signals, form beams in several beam pre-angled directions through beamforming technology, and then use signal processing methods to estimate the corresponding position of each beam point. depth, so as to obtain the topography and even landform information of the seabed. Resolution is one of the main performance indicators of multi-beam bathymetric sonar, which determines the clarity of terrain and landform images, and is also related to whether the structura...

AI Technical Summary

Problems solved by technology

The acoustic array structure of the multi-beam synthetic aperture sonar system adopts the Mills cross structure of the traditional multi-beam bathymetric sonar, which has disadvantages when the array structure is used for multi-beam synthetic aperture sonar: when the pulse transmission frequency is constant, When the sonar advances too fast, it will lead to spatial undersampling, which will cause azimuth ambiguity in the reconstructed image, that is to say, this matrix structure limits the surveying rate

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