Sound Velocity Correction Method Of Deep-water Multibeam And Its Application

The ocean is rich in natural resources.With the improvement of human living standards,land resources are becoming increasingly tense.The development and utilization of marine resources,especially deep-sea resources,will be an inevitable choice.In the process of scientific investigation,development,utilization and engineering construction of the ocean,a deep understanding of the complex seabed topography is the premise of the above work.The multi beam measurement system is one of the main equipments for acquiring the seabed topography,and the sound velocity correction is one of the main factors affecting the measurement accuracy of multi beam system.At present,many companies in China have successively equipped a variety of types of deep-water multi beam system,so it is necessary to discuss and study the problems existing in the application of sound velocity profile during the use of deep-water multi beam system.There are two problems in deep-water multi beam field data acquisition:one is the acquisition of full depth sound velocity profile,which can be divided into two parts:the acquisition of full depth sound velocity profile in the operation area and the acquisition of full depth sound velocity profile during navigation;the second is how to simplify the sound velocity profile while preserving the characteristics of the sound velocity profile,so as to meet the requirements of multi beam on the size of the sound velocity profile file.The main contents of this paper are summarized as follows:(1)This paper introduces the composition and principle of multi beam measurement system,summarizes the main errors that affect the accuracy of multi beam measurement,analyzes the main factors that affect the data quality of field acquisition of deep-water multi beam,introduces two common methods of sound line tracking,and analyzes the influence of different sound velocity errors on the accuracy of sounding by using the measured sound velocity profile data.(2)In order to solve the problem that the depth of the data of velocity profile is shallow when the velocity correction of multi beam in deep water is carried out in the operation area,the simple fitting method and EOF method are used to extend the sound velocity profile respectively,and the extended velocity profile is used to correct the velocity and analyze its accuracy.(3)In order to solve the problem that the sound velocity profile cannot be obtained quickly and effectively to correct the sound velocity in the course of navigation,this paper puts forward the method of sound velocity correction based on the earth system model FIO-ESM and the field XBT data developed by the first Institute of Oceanography,Ministry of natural resources,analyzes the accuracy of sound velocity correction,and proves its feasibility.(4)In order to solve the problem that the limiting of the sound velocity profile file size during deep-water multi beam field data acquisition,the method of streamlining the sound velocity profile is studied,and the D-P algorithm can effectively streamlining the sound velocity profile;the traditional D-P algorithm is improved,and the accuracy of the sound velocity correction of the simplified sound velocity profile is analyzed.The results show that the simplified sound velocity profile can effectively correct the sound velocity and improve work efficiency.