MEMS-based Inertial Navigation on Dynamically Positioned Ships: Dead Reckoning

:Dead reckoning capabilities are vital in ship navigation if position and heading references are unrealizable or lost. In safety critical marine operations such as dynamic positioning, the International Maritime Organization and classification societies require that the vessel possesses dead reckoning capabilities and position reference redundancy. In this paper, we conduct a full-scale experimental validation and comparison of the dead reckoning capabilities using two different high-rate and low-cost micro-electro-mechanical inertial measurement units. The full-scale experimental validation is achieved with two nonlinear observers, aided by gyrocompasses and position reference systems, in a dynamic positioning operation carried out by an offshore vessel in the North Sea. The dead reckoning performance is evaluated after ten minutes without aiding from position reference system measurements.