SLAM for pseudolite system comprising unsynchronised transmitters

In this paper the application of Simultaneous Localization and Mapping (SLAM) algorithms to a proprietary pseudolite system is presented. Time of Arrival measurements of multiple unsynchronised radio transmitters at reference rover positions are combined using an extended Kalman filter, in order to simultaneously localize both transmitters and movable receiver. In the case of unsynchronised transmitters, the SLAM approach must be adapted because the measurements from rover and transmitters are not simultaneously available, so that time constraints of the sensors must be taken into account and the measurements must be processed sequentially. Considerations relating to observability of the state variables are addressed. The efficiency of the algorithm is demonstrated using simulation data.