The Design Of ADCP System Based On OMAPL138 Processor Platform

The ADCP (Acoustic Doppler Current Profiler) system is based on the principle that we can get current profiler by measuring the amount of Doppler frequency of the echo signal corresponding to emission signal of the system. The doppler frequency is produced by the relative motion of the scattering bodies in the water, and the echo is stratified by time gate and being calculated to obtain velocity profile. In this paper, theoretical study about ADCP technology, Matlab simulation, the build of the ADCP system based on OMAPL138 processor platform, software’s development, system prototype debugging and preliminary experimental pond are completed.In this thesis, the basic theories that ADCP system used are detailed analyzed, including the principle of doppler velocity, ADCP beam structure, velocity coordinate transformation theory and so on. We make a detailed analysis about stratification of the water, accomplishing a simulated echo model with Matlab. The thesis finish the methods and algorithms’ research, analysis and comparison of flow measurements, includeing narrowband flow measurement, coherent flow measurement, and broadband flow measurement. To a conclusion that broadband flow measurement can improve the correlation and increase the time-bandwidth product of echo by pseudo random coded. In this paper, the corresponding flow measurement and bathymetric method’s broadband solutions are proposed. The mathematical derivation and demonstration of the phase estimation method which frequency estimation based on are completed, and the feasibility of the algorithm has been verified. Finishing the analysis of the broadband signal’s transmission characteristics and resolution, drawing a conclusion that broadband encoded signal has good time and frequency resolution as well as nice transmission characteristics. Detailed accomplishing process on DSP of broadband bathyme--tric and flow measurement’s algorithm are completed. In order to evaluating bathymetric and flow measurement’s performances, respectively, we do simulation and analysis on multiple aspects by Matlab, accomplishing the comparison and verification about the factors that influence their performances.On the system design aspect, adopting OMAPL138 ARM+DSP dual-core processor to meet with system’s different needs. We design each modle reasonably, completing the debug of each module’s hardware device and the whole system of collaborative modles. We complete software’s development of OMAPL138 processor based on CCS platform, and the DSP algorithm is optimized, so the whole system can be coordinated and in efficient operation. We do an assessment of the performance of DSP software features, as well as, the functions of the mainly DSP algorithm module are verified. The main hardware features of a whole system are tested, and the test results are analyzed and assessed by us. In a conclusion, hardware features and software features of the system have been properly validated. And in the anechoic pool, we made some experiments on assessing bathymetric and flow measurement capabilities.For the project cycle sake, yet, we have no time to do enough experiments for standard comparison of flow measurement. In the final of the paper, this thesis points some of my individual suggestions about the study of the ADCP system in the future to share, hoping that can bring some help to readers and our continuing research project.