Research On Resolving Velocity Ambiguity Algorithm Of Acoustic Doppler

Acoustic Doppler Current Profilers(ADCP)is an instrument that uses the doppler shift of echoes reflected by diffuser in fluid to measure the fluid velocity.It has a high measurement accuracy and a wide range of applications.In the same time,its velocity ambiguity problem limits its measurement range.Based on the research of previous researchers,the resolving ambiguity algorithms is improved.The effects of these algorithms are analyzed,and the performance of each method is evaluated.The research progress of doppler measurement techniques at domestic and foreign is described at first,the velocity ambiguity problem of ADCP system is introduced briefly.And the fundamental principles and resolving ambiguity problem of various doppler measurement techniques are researched in depth.Resolving ambiguity algorithms of pulse-coherent and broadband coded-pulse doppler measurement technique are the focus.Several existing resolving ambiguity algorithms is discussed in detail,the shortcomings of various algorithms in the speed-critical region is improved,and the feasibility of these improved algorithms is illustrated theoretically.In this thesis,matlab simulation experiments were carried out on various resolving ambiguity algorithms.The factors influencing the effect of algorithm's effect and the performance of these resolving ambiguity algorithms before and after the improvement are analyzed in detail.Experiments show that these improved resolving ambiguity algorithms have improved speed estimation accuracy in the critical velocity region.At the end of this paper,the half-physical simulation system was used to verify these resolving ambiguity algorithms.Experiments show that these algorithms can improve the speed range of the pulse-coherent and broadband coded-pulse doppler measurement technique,and the deblurring effect is good in the speed range.