Research on cooperative navigation for multiple UUVs
When multiple unmanned underwater vehicles(UUV) are in close proximity, only a few of multiple UUVs are equipped with high precise proprioceptive localization sensors and others can but be equipped with low precise ones for the reason of cost. Though rough localization can be achieved by a dead-reckoning(DR) system, the latter can acquire measurement information by the means of two modes with the former for improving localization accuracy. Two modes are required that all UUVs must carry acoustic communication equipments. One is acoustic broadcast communication in which distance measurements are obtained based on acoustic propagation time of flight (TOF). Another is detection in which distance and orientation are gained through receiving detecting echoes. Two modes both need the UUVs who have higher localization accuracy broadcast their positions in virtue of acoustic broadcast communication. The cooperative navigation algorithm based on extended Kaiman filter (EKF) can combine effectively the measurements with the rough state estimates of the DR system to make the UUV who is equipped with low precise proprioceptive localization sensors get better position estimates. The simulation results show the effectiveness of the algorithm.