The Design And Realization Of Broadband Doppler Velocity Measurement System’s Software

Broadband Doppler Velocity measurement system brings in pseudo-random code and wideband correlation technology on the base of traditional narrowband Doppler meter, its echo signals carries a richer Doppler shift information,which makes the system’s velocity measurement accuracy improved significantly, also the correlation character introduced by pseudo-random code greatly improves reverberation suppression and anti-noise-interference ability of the system, solves some problems exist in narrowband Doppler, improves velocity measurement performance.The main content of the thesis are as follows: determine the design strategies of system’s hardware platform and soft program, conduct the performance simulation of broadband frequency measurement algorithm with Matlab; use quadratic fitting method to improve the reliability of using correlated time delay estimation to solve the broadband velocity measurement ambiguity algorithm; complete the writing and debugging of system’s soft programs on the digital signal processing hardware platform, which uses 3 pieces of DSP doing their own duties; conduct the actual experiment on the Songhua Lake after system testing and debugging, analyse the experiment results, and make improving suggestions to the problems existed in the system.By hybrid programming with C language and assemble language the soft programs are written, in order to perform the function of the system accurately and efficiently. Three pieces DSP work in the mode of one master-two slaves, master DSP decide the work mode, slave DSP complete the calculating and processing of frequency measurement signals. In the progress of signal detection,cam-wide detection method is used to confirm the central position of echo signals; in order to increase the calculate efficiency of the algorithm, FFT instead of Self-Correlation method is accepted to solve the ambiguity of pulse-to-pulse Frequency measurement algorithm’s consequence. The soft of system is a good example of modular design, which can increase the robustness and portability of the soft.The consequences of system experiment testing and actual experiment on the Songhua Lake show that, Broadband Doppler instrument designed in the thesis can complete the velocity and depth measurement of the transporter precisely and steadily, the precision of velocity measurement can meet the technological specification. At the same time it also proves the superiority and feasibility of Broadband Doppler velocity measurement technology,presents the following improvement and reaches the expected targets.