The Research Of Improved Method For Ultra Short Baseline Position Precision

USBL(Ultra short Baseline) which needs only one transducer is widely used in AUV(Autonomous Underwater Vehicle) for its low price, convenience and easy to operate. But there are many problems in it, for example, the installation of system, the excursion and incline of ship, so the precision of USBL is poor. At present, the precision of USBL is about 1% abroad, and 3% at home. So it's a significant part to improve the position precision.This paper firstly studies the development and the theory of ultra short baseline positioning system. And the theory of acoustic positioning system is also studied in this paper. In this paper, the acoustic communication is also analyzed. It analyzes the noise and the loss of energy. And then the positioning precision is also analyzed. To increase the accuracy, it uses the Kalman filter to process the data. The position precision is improved by using the movement equation and measurement equation.It analyses the error, which is caused by the excursion and incline of ship. It also proposes the method to reduce the error by putting the value into depth sensor.Finally, the simulation is made, and the results validate the methods.