Three-dimensional forward looking audio-visual sonar system and method for small underwater vehicles

Abstract

The invention discloses a three-dimensional forward-looking acoustic-image sonar system for a small underwater carrier, comprising: a transmitting sonar array 1 for short-distance detection, which is composed of a plurality of primitives, and the distance between the primitives is half a wavelength; Sonar array 2, used for long-distance detection, is composed of multiple rows of sonar arrays, arranged in a circular arc in the horizontal direction, and arranged in a half-wavelength interval in the vertical direction; the receiving sonar array is composed of receiving transducers with a spacing of half a wavelength The units form a planar array, the central primitives are used for receiving, and the edge primitives are dummy. The system uses conventional beamforming technology to form multiple beams in the horizontal direction; within the beam, the phase method is used to obtain the incident angle in the horizontal direction; The incident angle; and use the echo arrival time to calculate the position of the scattering point in the three-dimensional space to obtain the acoustic image. It can realize front target detection with small front area, high resolution, long distance and wide coverage.

Description

technical field [0001] The present invention relates to three-dimensional forward-looking acoustic-image sonar technology, and more particularly, the present invention relates to a three-dimensional forward-looking acoustic-image sonar system and method based on direction-of-arrival estimation for small underwater vehicles. Background technique [0002] Underwater vehicles (such as autonomous underwater robots, cable-controlled underwater robots, etc.) need to use three-dimensional forward-looking audio-visual sonar to detect obstacles and targets in the three-dimensional space in front of the carrier and obtain three-dimensional audio images. Due to the speed requirements of underwater vehicles , Space and power consumption constraints require the three-dimensional forward-looking audio-visual sonar to have the characteristics of small size, light weight and low power consumption. [0003] The existing forward-looking imaging sonar mainly adopts the following two schemes to...

AI Technical Summary

Problems solved by technology

However, due to the use of planar arrays, the number of array elements is large and the system is complex, it is limited when installed on underwater vehicles, especially not suitable for small underwater vehicles, and its resolution in the vertical direction is limited by Fourier transform, so the resolution is low

[0005] At present, the development of three-dimensional forward-looking sonar has been serialized, and the technological level is very high, but the resolution of the developed sonar is limited by the conventional beamforming, that is, the beam angle width Δθ~λ / L, λ is the wavelength of the center frequency, and L is Sonar array length

Generally, the size of the three-dimensional forward-looking sonar is large, and it is not suitable for installation on small underwater vehicles such as small autonomous underwater vehicles (AUV). Currently, the first multi-beam forward-looking imaging is mainly installed on small AUVs. Sonar, cannot directly give three-dimensional information of the target

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