Sensor and Navigation Systems
Thor Inge Fossen · 2011
Conventional ship and underwater vehicle control systems are implemented with a state estimator for processing of the sensor and navigation data. This chapter discusses model-based wave filtering and observer design using linear wave response models. This is one of the most important features of a high-precision ship control system. The best commercial autopilot and DP systems all have some kind of wave filtering in order to reduce wear and tear on the steering machine, as well as thrust modulation. Low-pass and notch filters can be used to reduce motions induced by ocean waves in the feedback loop. The chapter summarizes the most useful results for the design of discrete-time and continuous-time Kalman filters for marine craft. An inertial measurement unit (IMU) can be integrated with a satellite navigation system in a state observer to obtain estimates of generalized position and velocity in 6 DOFs. Controlled Vocabulary Terms Kalman filters; notch filters; ocean waves; satellite navigation; sensor systems; ships; underwater vehicles