A Method for Effectively Improving the Measurement Accuracy of Acoustic Doppler Velocity Profiler Flow Direction

Abstract

A method for effectively improving the flow direction measurement accuracy of an acoustic Doppler current profiler relates to the acoustic Doppler current profiler. Firstly, by establishing a mathematical model, analyzing the relationship between the change of the magnetic north angle and the change of the final flow direction, it is concluded that when only the change of the magnetic north angle exists, the change of the angle is equal to the change of the flow direction. On this basis, the least square method was used to fit the error of the flow direction affected by the magnetic field, and the fitting coefficient was used to compensate the ADCP measured flow direction output. Compared with the standard flow direction, the root mean square value of the error caused by the magnetic influence of the flow direction can be finally reduced by about 70%. It can effectively compensate the flow direction error caused by the internal magnetic compass of ADCP under the interference of the environmental magnetic field within the azimuth range of [0,360°), so that the flow direction measurement accuracy can be greatly improved in all directions. It has engineering guiding value for long-term fixed-point current measurement in ocean observation.

Description

technical field [0001] The invention relates to an Acoustic Doppler Current Profiler (Acoustic Doppler Current Profiler, ADCP), which belongs to the technical field of marine observation instruments, and in particular relates to a method for effectively improving the flow direction measurement of an Acoustic Doppler Current Profiler for correcting the actual flow direction error of the ADCP. method of precision. Background technique [0002] ADCP is an instrument that uses the principle of acoustic Doppler to measure the velocity and flow of water flow. Using the offset between the echo frequency received by the ADCP transducer and the transmission frequency, the velocity of the particles in the water can be calculated to obtain the movement velocity of the water flow, and then the flow of water flowing through the section within a certain period of time can be known. [1] . ADCP has become an important flow measuring instrument in oceans, rivers and other water bodies. ...

AI Technical Summary

Problems solved by technology

[0005] Among the analysis of many error sources and countermeasures, there is little discussion on the magnetic north angle output error caused by the internal magnetic compass of ADCP affected by various magnetic fields in the environment—the flow direction error caused by the error

For the suppression of flow direction error caused by misalignment, the general method is to solve it by connecting an external compass or GPS [10,11] , there is no relevant report on the mathematical analysis and mathematical correction of the ADCP flow direction output affected by the differential

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