Relative positioning of multiple underwater vehicles in the GREX project

This paper discusses estimation of relative positions of a group of autonomous underwater or surface vehicles. The solution to this problem is crucial for performing cooperated missions. It is show that the relative positioning problem is solvable when dead reckoning data is combined with mutual range data provided by some additional device, e.g. by acoustic telemetry. This data has to be distributed via an acoustic underwater communication network among the swarm members. A simple concept for the solution of the relative positioning problem is presented. This is achieved by implementing a recursive variant of a trilateration technique by means of an Extended Kalman Filter.