초음파 거리계를 갖는 수중 복합항법시스템의 초기오차 수렴 특성

Abstract

This paper presents the error convergence of a hybrid navigation system for underwater vehicles, which is based on an inertial measurement unit (IMU) accompanying a range sensor, a Doppler velocity log (DVL), a magnetic compass and a depth sensor. A measurement equation of the range sonar is modeled and augmented to the conventional IMU-DVL navigation system. 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. This paper demonstrates the improvement on the navigational performance of the hybrid system with the range information, especially focused on the convergence of the estimation error of underwater vehicles' initial position. Simulations are performed with the experimental data obtained from a rotating arm test with a fish model. The convergence speed and conditions of the initial error removal are examined with Monte Carlo simulation. In addition, numerical simulation was conducted with an AUV model in lawn-mowing survey mode to illustrate the robustness for the initial position error of the hybrid navigation system.