Velocity Profile Data Processing And Error Control In ADCP

Acoustic Doppler Current Profiler (ADCP) is sonar equipment, which works based on the principle of acoustic Doppler. By transmitting and receiving multiple beams at the same time, it can be used to measure the river flow velocity and flow rate quickly and with good precision. As an instrument of velocity measurement, ADCP has been applied more and more to modern hydrology test and the research on technology of ADCP arouse people’s attention for increasingly. The quality of velocity data will be influenced by complex water environment and error in operation in ADCP. Therefore, the research on how to obtain accurate velocity and flow data is essential. The major work of this paper is to improve the precision and quality of the velocity data and flow by analyzing all kinds of error sources and researching error correction algorithm in ADCP. The specific research contents are as follows:First of all, the process of data processing is described in velocity data processing module of ADCP. The complete data processing from the Doppler frequency shift to flow is given, and all the parameters needed in the process are analyzed in detail.Secondly, the error sources and factors that affect the accuracy and stability of data in the process of measurement are analyzed. The systematic error mainly involves the radial velocity error introduced by the velocity calculation, the error introduced by the carrier swing, ADCP transducer installation errors, blind and side beam, random error includes external auxiliary equipment (temperature sensor, pressure sensor, attitude sensor, GPS) random error itself. The influence of various errors on the performance of flow measurement is discussed in detail.Then, for a variety of system error, the reasonable correction algorithm is proposed. The simulation results show that, the algorithm can effectively reduce the system error introduced by error source, so that the flow measurement accuracy is improved significantly. Based on the above algorithm, a set of general error calibration is designed to correct various errors, and the velocity data are averaged to reduce the impact of random error.Finally, on the basis of theoretical research, the whole process of velocity profile data processing and error calibration algorithm are implemented in the actual system development board. Focus on the software design and debugging process of the temperature sensor and the attitude sensor. Due to the progress of experimental conditions and constraints of the project, error correction algorithm is verified partially.