Design of inertial navigation systems for marine craft with adaptive wave filtering aided by triple-redundant sensor packages

Abstract

Marine craft feedback control systems typically require estimates of position, velocity and heading where the wave-induced motions should be suppressed. This paper presents a strapdown inertial navigation system with adaptive wave filtering. Wave filtering based on inertial navigation systems differ from previous vessel-model-based designs that require knowledge of vessel parameters and mathematical models for estimation of thruster and wind forces and moments based on auxiliary sensors. The origin of the inertial navigation system's error states is proven to be uniformly semiglobally exponentially stable. The wave-filtering scheme uses the estimated states of the inertial navigation system to separate the low-frequency motion of the craft from the wave-frequency motions. The observer structure also allows for estimation of the time-varying encounter frequency by using a signal-based frequency tracker or an adaptive observer. Finally, properties following from the triple-redundant sensor packages have been utilized to obtain optimal and robust sensor fusion with respect to sensor performance and faults. Copyright © 2015 John Wiley & Sons, Ltd.