Tightly-coupled integration of GPS/INS and simultaneous localisation and mapping

This paper presents a tightly integrated navigation system combining global positioning system (GPS) and inertial-based simultaneous localization and mapping (SLAM) for UAV platforms. GPS raw measurements, called pseudorange and pseudorange rate, are directly fused to an inertial SLAM filter. A compressed form of unscented filtering is implemented by partitioning the map into a local and global one. The performance of the proposed method is analysed using a high-fidelity 6-degrees-of-freedom simulator, demonstrating accurate and robust navigation even under a single satellite observation. The information gain of bearing and elevation angles is further analysed offering effective sensing strategies.