Robust multi-loop airborne SLAM in unknown wind environments

This paper presents a robust multi-loop airborne SLAM structure which also augments wind information. The air velocity observation from an air data system can be used to estimate the error of the on-board Inertial Navigation System (INS). However, due to a priori unknown wind velocity, it cannot directly be used for this purpose. This can be tackled by augmenting the unknown wind velocity into the state vector of SLAM, simultaneously estimating INS, map and wind. This paper proposes a multi-loop SLAM architecture, where the periodic velocity-level SLAM loop limits the INS errors of the velocity effectively, and the aperiodic position-level SLAM loop bounds the overall position error growth. This can significantly increase the consistency of airborne SLAM at the time of loop closure. Simulation results show that the unknown wind vector can be estimated consistently and the robustness of airborne SLAM improves significantly.