Quadrotor Inertial Navigation Aided by Vehicle Dynamic Model: A Nonlinear Observability Analysis

Previous studies have shown that quadrotor inertial navigation with aiding from a vehicle dynamic model (VDM) can be applied for short periods of flight without global navigation satellite system (GNSS) measurements. However, quadrotor inertial navigation flight experiments were performed without conducting the observability analysis which is necessary to guarantee state convergence. To investigate the claims of these studies, we conducted a nonlinear observability analysis on the recent quadrotor VDM. The analysis shows that the position of the quadrotor is unobservable, but the velocity is still observable. This analysis confirms the experimental results from previous studies that VDM-aided quadrotor inertial navigation is only applicable for short periods of GNSS-denied flight. However, a further analysis gives an interesting finding that the VDM parameters are observable provided only an inertial measurement unit (IMU) sensor. In theory, online estimation of the VDM parameters are still possible and may improve the performance of VDM-aided quadrotor inertial navigation.