거리센서를 이용한 관성 및 도플러 속도기반 수중항법시스템의 성능개선

Abstract

This paper presents an improvement of inertial- Doppler underwater navigation system for unmanned underwater vehicles (UUV) using a complementary range sonar. The inertial-Doppler navigation system is generally based on an inertial measurement unit (IMU) and a Doppler velocity log (DVL) accompanying a magnetic compass and a depth sensor. Although the conventional navigation system updates the bias errors of the inertial sensors and scale effects and the bias errors of DVL, the estimated position slowly drift as time passes. This paper proposes a measurement model with additional range sonar to improve the performance of the IMU-DVL navigation system for underwater vehicles’ positioning and tracking. The proposed navigation model based on inertial navigation systems includes the scale effects, the bias errors of the DVL, and the error model of a range sonar, where the order of the system states is 21. An extended Kalman filter was adopted to propagate the error covariance, update the measurement errors and correct the state equation when the external measurements are available. Simulation conducted with the 6-d.o.f. equations of motion of an AUV in lawn-mowing survey mode illustrates the effectiveness of the IMU-DVL navigation system assisted by additional range measurement.