Research On Simulation Testing Method Of The Doppler Velocity Sonar

Doppler Velocity Sonar measures the frequency shift information of beam-domain echo signal using the Doppler Effect principle,to achieve the measurements of absolute velocity relative to the seafloor and velocity relative to the layer.It is widely used in marine resources development,ocean observation,navigation channel measurement and many other fields.Effective testing is an important link of equipment development,but the traditional sea test and pool test spend too much time and resources.In response to these situations,need to research a method to perform the functional test of the sonar in the terrestrial environment.Based on the envelope statistical analysis of the Doppler Velocity Sonar experimental data,the paper establishes a beam-domain echo signal model of the seafloor and the water layer.Firstly,envelope fitting results of four common distribution models and experimental data are given,and the K-distribution model with the best fitting effect is applied to echo modeling.Then the doppler velocimetry theory and the multipoint scattering theory are described,and the influence factors of the sonar working parameters and the marine environment parameters are synthetically considered,based on these,the model of the echo signal is established.Finally,the simulation echoes are obtained which have the same waveform,spectrum and envelope distribution feature with the experimental echo.The echo model is applied to the simulation testing software which is designed on virtual instrument development platform Labwindows/CVI.The software mainly consists of two parts,echo signal simulation and display of measurement results of the sonar,with the characteristics of the low cost and portability.The NI's PCI6733 D/A card is chosen to realize the real-time simulation of the echo signal according to the parameter setting,as the test signal source of Doppler Velocity Sonar.Comparing the sonar measurements with the parameters of the echo simulation,it can be checked if the sonar device is working properly.Through the software function test and the on-line debugging trial,the system runs well and the state is stable,which achieves the expected goal.