Underwater control point positioning method considering surface acoustic velocity and coordinate prior information

Abstract

The invention provides an underwater control point positioning method considering surface acoustic velocity and the coordinate prior information and belongs to the technical field of underwater positioning. According to the method, surface acoustic velocity and coordinate prior information are considered, acoustic velocity errors of a circular sailing method and acquisition of control point planecoordinate prior information are analyzed, control point coordinates and a water depth value measured by a pressure sensor are regarded as random quantities, and a water depth observation value is endowed with a first empirical variance which is 0.1% of the water depth according to experience; and finally, coordinates of the control points are solved by adopting a generalized least square principle. Simulation of 50m and 1500m water depth positioning experiments proves that under the condition of not using a sound velocity profile, only surface sound velocity and coordinate prior information are considered, a high-precision positioning result can also be obtained, the ship hour can be effectively saved, and operation efficiency is improved. The method is high in practicability, stable andreliable in result and high in efficiency, and is mainly used for transmitting the absolute coordinate reference of the underwater control network.

Description

technical field [0001] The invention belongs to the field of underwater positioning, and in particular relates to an underwater control point positioning method in consideration of surface sound velocity and coordinate prior information. Background technique [0002] The seabed control network is the basis of ocean geodesy, which is of great significance for detecting and monitoring ocean plate movement and crustal deformation. In the process of absolute position calibration of control points, the traditional method is to use ship-borne GPS and underwater ranging equipment to intersect to determine the coordinates of seabed control points. But there are disadvantages: the ranging accuracy is greatly affected by the sound velocity error, and a small sound velocity error will cause a sharp drop in positioning accuracy, especially in deep sea positioning, the positioning error caused by the sound velocity error cannot be ignored. In order to weaken the influence of the sound v...

AI Technical Summary

Problems solved by technology

But there are shortcomings: the distance measurement accuracy is greatly affected by the sound velocity error, and a small sound velocity error will cause a significant drop in positioning accuracy, especially in deep sea positioning, the positioning error caused by the sound velocity error cannot be ignored

In order to weaken the influence of the sound velocity error and improve the positioning accuracy and operation efficiency, some scholars have proposed the circular navigation method. Due to the symmetry of the survey ship trajectory, the influence of the sound velocity error can be effectively weakened when the least squares is used to solve the control point coordinates. However, this method has the problem of low accuracy of vertical solution and instability

[0003] The accuracy of the vertical solution of control points depends on accurate distance measurement, and accurate sound velocity profile is the key to accurate distance measurement, however, the sound velocity profile is related to water temperature, salinity and pressure, and changes irregularly with time and space , so it is difficult and time-consuming to obtain an accurate sound velocity profile

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