New method of correction for underwater inertial navigation system

Inertial navigation systems (INS) can measure its own movement through its core component-Inertial Measure Unit (IMU), thus INS is a kind of autonomous navigation system and are used widely in various kinds of vehicles. The position measurements from INS are very accurate over a short time period, but the position data will drift more and more over time. The INS of underwater vehicles needs to work for long time, and the position error of INS accumulates with time. Normally, INS/Radio/Satellite/Celestial combined navigation methods are used to correct the accumulated errors. However, the nontransparent space of underwater limits the application of these methods, thus INS cannot use these methods to correct their errors and it is necessary to seek new method of correction. In this paper, firstly the analyses of various kinds of typical hydroacoustic position systems and the possibilities to combine them with INS are described, then a new method which is to combine SSBL with INS for error correction of INS is presented, finally the principle algorithm of this new method is provided.