The Optimization And Research Of ADCP System’s DSP Algorithms

Acoustic Doppler Current Profiler (ADCP) is a kind of highly efficient hydrographic survey equipment, which estimates the water flow rate by figure out the Doppler shifts in the water scattering echo signal. ADCP can measure the flow rate in real time of the aqueous layer of different depths, it is widely used in water quality monitoring, ocean observations, underwater navigation, etc. Based on the previous, original broadband ADCP system is debugged and improved. System measuring algorithms is optimized and function is featured. Combined with field experiments, the actual measurement data is analyzed, laid the foundation for further research.This paper introduces the Doppler flow measurement technology development process at home and abroad. Doppler flow measurement technology principles and methods is researched, and Echo Modeling and complex autocorrelation frequency estimation methods were studied and simulated. On this basis, the author conducted ADCP system software design, debugging and improvement on OMAP-L138 hardware signal processing platform.This paper focused on the selection of the measurement signal, the measurement content optimization algorithms, data storage and transmission and so on. In the measurement signal selection, the author selected the form and length of flow measurement signal and studied the algorithms of automatically adjust the length of the bottom tracking signal. Based on the theory analysis, the author developed a thickness selection strategy, selected 16 kinds of alternative transmission signal, and designed control process to automatically adjust the length of the signal. In terms of measurement optimization algorithm, the author made the theoretical analysis and simulation analysis of the influence to flow measurement caused by the bias in echo signal, and designed offset removal algorithm to improve the stability of flow measurement results. Two kinds of fast algorithms to measure water depth were designed and implemented. Experimental tests show that both algorithms can be the premise of ensuring high accuracy and make sounding Processed reduced to about 1.7% of the original. An improved bottom tracking algorithm were designed and implemented, simulation and experimental tests show that the algorithm can greatly improve the stability and accuracy of bottom tracking measurements. The author also proposed and implemented a method that can greatly improve the data output rate. In addition, the author implemented SD card data storage and USB data transfer functions, laid the foundation to self-contained measurement. Finally, the process of the flow measurement experiments was described, and the measurement results of experiments were analyzed to verify the reliability and feasibility of the system hardware and software.