Robust observer design for underwater vehicles

In this paper we propose a new observer system for underwater vehicles. The main design objective behind this strategy is to reduce the effect of the destabilizing Coriolis and centripetal forces and moments. For low cost vehicles with limited measurement equipment, these forces and moments represent a significant challenge for automatic control when the forward speed is high. However, by explicitly utilizing an estimation of the current velocity in the observer, this paper shows that a high degree of robustness relative to environmental disturbance and measurement noise is achievable. This is strongly related to the estimation of the destabilizing Coriolis and centripetal forces and moments. Furthermore, this observer scheme has shown to be tolerant to large error in the position measurements, which is a common occurrence in underwater navigation.