MIMO array depth sounding method by means of emission subarrays

Abstract

The invention provides an MIMO array depth sounding method by means of emission subarrays. The two subarrays of an emission array are parallel and aligned to each other, the distance between the two subarrays is equal to the result obtained after the number of array elements of a receiving array multiplies the distance of the array elements, emission signals in the subarrays are related, emission signals between the subarrays are independent, self-correlation functions of the emission signals of the two subarrays have identical main lobes and identical low side-lobes, the two subarrays emit pulse signals at the same time and illuminate a single stripe simultaneously, echoes are collected through the receiving array, and matched filtering processing is carried out on the echoes by means of the emission signals of the emission subarrays; multi-beam processing is carried out on output of matched filtering to form multiple receiving beam footprint covering depth measuring stripes; arrival delay of the echoes is estimated, the delay is converted into the coordinate of a receiving beam footprint, and accordingly the disperse depth of each stripe is obtained. According to the method, on the premises that the physical size of a receiving linear array is not increased and emission signal frequency is not increased, the course cross resolution ratio of a multi-beam depth measuring system is multiplied.

Description

technical field [0001] The invention relates to an array imaging method. Background technique [0002] The multi-beam bathymetry system installed on small underwater platforms (such as AUV and ROV) usually adopts Mills cross array, that is, the mutually perpendicular transmitting linear array and receiving linear array (de Moustier C. State of the art in swath bathymetry survey systems.International Hydrographic Review, Monaco, 1988:25-54. Wu Yingzi. Research on Terrain Tracking and Data Processing Technology of Multi-beam Bathymetry System. Doctoral Dissertation of Harbin Engineering University, 2002.). Take the cross array in Mill's cross array as an example, such as figure 1 As shown (where the triangle "Δ" represents the transmitting array element, and the circle "O" represents the receiving array element), in order not to destroy the line shape of the AUV, the physical size of the cross array must not exceed the horizontal and vertical dimensions of the AUV when deploy...

AI Technical Summary

Problems solved by technology

However, as the receive main lobe moves from the central beam to the edge beams, the receive aperture becomes progressively smaller and the beam footprint expands, i.e., the resolution of the edge beams is lower than that of the center beams (see image 3 )

To increase the aperture of the receiving linear array, the traditional method is to increase the size of the array or increase the frequency of the transmitted signal, which in turn faces the problems of AUV internal space limitations and increased absorption loss

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