Deep sea multibeam sound ray accurate tracking method

Abstract

The invention discloses a deep sea multibeam sound ray accurate tracking method. The method mainly comprises the steps of (1) establishing a spatial and temporal variation ocean temperature and salinity field model on the basis of the comprehensive analysis of influence factors of sea surface temperature and salinity and with the integration of marine satellites and Argo buoy multiple-source marine physical hydrological observation data, (2) calculating each beam initial incident angle through analyzing the influence of a ship instantaneous attitude on a beam initial incident angle and considering a ship attitude, (3) calculating a sound speed and an inversion sound speed based on an empirical orthogonal function through the spatial and temporal temperature and salinity field at a sound speed profile no-measured area, obtaining the average value of sound speeds obtained by two methods at a corresponding point as the sound speed of the point, and thus calculating a three-dimensional sound speed profile model, (4) constructing an efficient constant gradient sound ray accurate tracking model, and (5) providing a sound ray tracking precision evaluation method. According to the method, the influence of the ship attitude on the beam initial incident angle is considered, the precision of beam footprint coordinates can be greatly improved.

Description

technical field [0001] The invention relates to a sound ray precise tracking method, in particular to a deep-sea multi-beam sound ray precise tracking method. Background technique [0002] As we all know, underwater target detection is the basis for investigation and research of seabed resources, marine environment development and marine engineering design, and multi-beam bathymetry, as the main means of high-precision detection of underwater targets, can be used to achieve high-precision detection of seabed topography , Accurate detection and development of seabed resources, layout and observation of underwater reference points, underwater auxiliary navigation, early warning of geological disasters such as submarine landslides and collapses, auxiliary surveys for the construction of cross-sea bridges, etc. At present, the main factors affecting the accuracy of multi-beam sounding are tidal level changes, transducer draft changes, swell changes and sound ray tracking. Among...

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Problems solved by technology

[0013] (1) The current temperature-salt deep-field model has a low resolution and has not been well applied in acoustic ray tracking;

[0014] (2) The calculation of the initial incidence angle of the beam does not take into account the influence of the hull attitude, resulting in low calculation accuracy of the beam footprint coordinates;

[0015] (3) In the process of data processing, the sound velocity profile of the measured point or the sound velocity profile with a large error calculated according to the empirical formula of sound velocity is used to replace the sound velocity profile of the unmeasured point, which often causes deformation of the seabed topography (both sides upturned or downturned). Collapse), the edge water depth value has an error of about 15%, which is unacceptable

[0016] (4) In the calculation of the travel time of each water column, the traditional intralayer constant gradient acoustic ray tracing model replaces the average sound speed on the real arc with the average sound velocity in the vertical direction, resulting in the presence of sound rays in the travel time of each water column Error, which affects the accurate calculation of the entire travel time of the sound ray, and eventually leads to a large error in the homing calculation of the beam

Secondly, in the process of thousands of meters of deep-sea acoustic ray tracking, the water column layer with a small gradient is not filtered and merged, resulting in a long time-consuming acoustic ray tracking, which seriously affects the efficiency of beam homing calculations

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