Calibration Of Underwater Acoustic Target Positioning System

More and more attention is paid to the underwater acoustic positioning technology due to the fast development of ocean exploitation. The underwater acoustic positioning system manufacturer, especially the named consignee needs to calibrate the system accuracy in order to check and accept it. Based on practical project and aiming at manufacturing the underwater acoustic positioning calibration system with high precision, the thesis researches the hardware design, positioning accuracy, correlative algorithm, display console software of the calibration system and analyses the results of the land validated experiment at last.In order to give the precise coordinates of the underwater target, the buoy is designed as carrier of the underwater acoustic positioning calibration system, which has high maneuverability compared with ship. The correlative factors influencing accuracy of the calibration system are researched such as bending distortion of underwater columniform lever, heading angle measurement error, pitch and roll angle measurement error, synchronization time error between GPS data and attitude gyro data, hardware installation error and GPS positioning error and so on. The integrated positioning accuracy of the calibration system is also analyzed in the thesis. The received data of GPS belong to WGS-84 coordinate reference frame, which should be transferred to BJ-54 reference frame. The transfer of axes between WGS-84 and BJ-54 and the algorithm of procedure are presented in the thesis. The geodetic coordinates of underwater reference point are resolved using coordinate conversion algorithm matrix, which utilizes both GPS data and attitude gyro data of the calibration system. The display console software is developed by VC++ 6.0 according to the requirement of calibration system, which received GPS and attitude gyro data using two serial ports real-timely and synchronously. The software is able to show the traces of the GPS antenna and underwater target, save data and playback them.In the end, the land validated experiment of the calibration system is done and the error factors of it are researched in detail. The results of the experiment show that the positioning error of the underwater positioning datum mark, which is considered as simulated target, measures up to the standard of the project and is able to provide the position criterion for underwater acoustic positioning system on the sea.