Study Of Digital ADCP Signal Processing System Based On Software Radio

The task of this thesis is developing the digital Acoustic Doppler Current Profiler(ADCP), which is a part of the project, a small multi-parameter marine environment detection buoy under China national 863 programs. The digital Acoustic Doppler Current Profiler signal processing system is developed based on Software Radio(SR) which is the core of the whole device.At present, ADCP technique is qualified for the advantages of multi-function, low consuming, small bulk, cheap material and so on, which are difficult to realize. The whole digital method proposed in the project with the import of SR idea is to improve the flexibility and adaptation.The instrument we have developed will open a new situation for our nation, which can be applied for the observation of water current velocity, silt concentration and ice thickness. The translation to standardization of this technique will break the situation of foreign monopolization and reduce the examination cost greatly.This dissertation achieves the following innovative points:1. The complete digital solution of ADCP is realized with the induction of SR idea. Then the difficult matching problems of traditional analog system are solved. Correspondingly the processing speed and flexibility are enhanced greatly.2. The application of Direct Digital Synthesis(DDS) technique in the system can send different acoustic waves with DSP and CPLD controls, which enriches the multi-function capability. The hardware program for the ADCP signal processing flat is designed with ASIC technique that contains flexible logic control, space partition for IO, data and program, hardware watchdog, translation of serial port to parallel port and generation of PN sequence.3. A novel Enhanced Least Mean Square(ELMS) algorithm is proposed in the thesis. Both the ELMS and the classical coding Pulse-to-Pulse algorithm are integrated in the hardware system, which improves the adaptability. The DSP software program is completed with Object-Oriented, circular order method. This scheme can make the user of ADCP pay more attention to the external junction than the inner details. The function of changing different modes for different purposesimplies the multi-parameter advantage.4. The prototype has passed the board testing, flume trial, comparing measure in the sea and calibration in Wuxi city, Jiangsu province. The testing results show that the instrument runs fine.