Study On Method Of Combined Doppler And Error Analysis

Acoustic Doppler technology is a key technology of Acoustic Doppler Current Profiler(ADCP).There are many kinds of velocity measurement technology based on acoustic Doppler,including narrow-band coherent velocity measurement technology,narrow-band non-coherent velocity measurement technology and broadband velocity measurement technology.The techniques of coherent and non-coherent Doppler velocimetry both have their own advantages,but at the same time there are shortcomings and defects.Aiming at the problems,this thesis does the following work:(1)This thesis summarizes the characteristics of two kinds of flow measurement systems,combines the advantages of the two,and puts forward a technical method to solve the above problems.(2)In this method,a deterministic algorithm of integer factor n of the key parameter in velocity fuzzy is proposed,and theoretical error analysis is carried out.(3)In the case of low SNR,the deterministic algorithm of integer factor n is prone to generate large errors,that is,it will form relatively obvious impulse noise.The error probability of integer factor n is reduced by variable transfer and adaptive algorithm.Theoretical error analysis is used to discuss the effect of the algorithm on error reduction.(4)The measurement results of the combined doppler system have small error,more accuracy and no fuzzy velocity by comparing the measured results of various doppler systems under different SNR conditions.The combined doppler system with adaptive algorithm can obviously reduce impulse noise and work in a larger SNR range.(5)The measurement effect of mixed Doppler system is verified by experiment.The experiment is divided into static experiment and dynamic experiment.Only Gaussian white noise exists in the static experiment.In addition to Gaussian white noise,there are other kinds of noises in the dynamic experiment.