Multi-beam and low-glancing-angle beam homing method based on laser-point cloud used as constraint

Abstract

The invention discloses a multi-beam and low-glancing-angle beam homing method based on a laser-point cloud used as a constraint and belongs to the technical field of hydrographic surveying and charting. The multi-beam and low-glancing-angle beam homing method comprises the following steps: firstly, constructing a three-dimensional sound velocity field with a revised shallow layer in a region by using an experience orthogonal function analysis method according to a plurality of sound velocity sections in an offshore region and a surface layer sound velocity value along the near part of a track line, so as to finish the revising of an initial sound velocity of depth measurement data; then, taking a characteristic point extracted by the same-target laser-point cloud as an outermost sound wave beam constraint to obtain coordinate deviation of the characteristic point with the revised initial sound velocity; accordingly calculating an initial rotary angle and an initial amplification coefficient in a low-glancing layer so as to weight and interpolate the rotary angle which corresponds to each residual beam and is more than 60 degrees and the amplification coefficient according to angle linearity; finally, realizing geometrical correction of the beams. With the adoption of the method provided by the invention, the accurate homing of the sound wave beams in shallow-layer seawater is realized, and the problem of seamless splicing of upper and lower point clouds of waterlines is solved.

Description

technical field [0001] The invention relates to the technical field of marine surveying and mapping, in particular to a multi-beam low-grazing angle beam homing method based on laser point clouds as constraints. Background technique [0002] Seabed topography in shallow water areas such as remote islands, reefs, coasts, and tidal flats, and near-shore water topography surveys have always been a hot spot in the field of surveying and mapping at home and abroad. For this reason, sea-land integrated measurement methods represented by ship-borne laser technology and airborne radar technology have emerged one after another at home and abroad. Among them, the airborne radar technology is difficult to be applied in the actual measurement work due to the problems of difficulty in research and development, high price, and rapid energy loss of laser light propagating in seawater. The ship-borne laser technology equipped with multi-beam uses laser and sound waves to measure water and ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the above-mentioned technical problems existing in the prior art, the present invention proposes a multi-beam low-grazing angle beam homing method based on laser point cloud constraints, which is reasonably designed, overcomes the deficiencies of the prior art, and solves the The problem of seamless splicing of online and offline point clouds

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