Underwater Target Precisely Positioning System

Underwater target precise positioning system comes from National Science and Technology Support Plan Subject-the technology of fast approaching target in emergency on maritime, whose purpose is to locate the submarine ships in distress and other target. And then, the position data is real-time displayed on upper PC so that the client can make specific rescue plans, which improves the efficiency of rescue and reduce economic investment.The system consists of rescue ship and ROV. There are USBL's transceiver, attitude instrument, compass and GPS on rescue ship. USBL's transponder, imaging sonar, attitude instrument, compass and altimeter are installed in ROV. First, use USBL to achieve the location of ROV, whose positioning error is corrected by attitude instrument and compass. And then calculate the latitude and longitude of ROV with the help of rescue ship's GPS. Second, Based on ROV, achieve the location of the target by imaging sonar and other sensors. Finally, conclude the position of the target. When doing general design plan, the writer analyzes the characters of imaging sonar and mechanical scanning sonar from position principle, data real-time and positioning accurary, and determines the instrument model. Then according to the chosen instrument and auxiliary sensors, describes the whole positioning system in detail.Let's come to software realization, the subject achieves the upper PC display and control software based on Visual C++ 6.0 environment. Use serial ports and multithreading technology to capture data of sensors and sonars. Using image processing technology analyze imaging sonar to extracte distance information related. Complete positioning algorithm and error correction, which is the core of the positioning system algorithm. Complede the basic orientation of calculation and related coordinates rotation correction, coordinate transformation between geographic location and longitude and latitude. Use circular linked list to store data. Monitor the sensors data and alarm if necessary. The final positioning data is diaplayed in visual window.Finally, through theory experimental data to analyze the USBL's positioning accurary, and the worst error is 4.12m, which meets the demand of the client.