Design And Realization Of Signal Processing For Doppler Velocity Log

Doppler Velocity Log is a precise instrument, which is used to measure ship velocity with sound wave in water on the theory of Doppler effect. This kind of Log can measure the ship's absolute velocity relative to the seabed and the velocity relative to the current layer. Its advantage is that better velocity measurement precision can be obtained on the condition of low velocity of ship. In recent years, because of the application of Phased-array technology, Doppler Velocity Log needs not the compensation for sound velocity, so it avoids the error which sound velocity measurement brings.In this thesis, the hardware and software design of signal processing system based on Phased-array Doppler Velocity Log. were researched The main work of this thesis contains three parts of content: Hardware design and interface circuits debug of digital signal processing system; DSP software design and implement; debug and experimentations of the system in lake and sea.On the core module design of digital signal processing system, the whole system's data processing center is three chip of TI's fixed-point DSP TMS320VC5509A, which is master-slave frame; one chip of CPLD take charge of logic control; Serial communication between DSP and PC is realized by universal asynchronous receiver/transmitter TL16C752B; Two chips of Analog-to-Digital converter belong to serial interface mode. In this thesis, the design and function of interface circuit based on digital signal processing system is presented in detail.The signal processing software of system was realized on the hardware platform above. In this thesis, the DSP software is accomplished by mixing C language and Assembly Language. Many central functions are realized in this part of signal processing software, including controlling Transmitter, data collecting, signal detecting, data saving, velocity calculating, communicating with PC through RS422, and so on. This system apply complex correlation algorithm, which the merit consists in its small account and accuracy. After a lot of experimentations in lake and sea, the experiment results show the validity of system scheme and stabilization of hardware circuit are very good And the signal processing software run all right. It is also proved that this system is suitable for different depth and bottom material.