Observability Analysis of Position Estimation for Quadrotors With Modified Dynamics and Range Measurements

This study performs a nonlinear observability analysis on range assisted inertial navigation system (INS) for quadrotor micro-aerial vehicles (MAV). The INS is formulated incorporating the quadrotor dynamics with aerodynamic drag forces. The observability analysis is carried out for cases where three and two range measurements are available. The analysis facilitates the range assisted localization of MAVs when there are less than four range measurements are available. The primary objective of this study is to identify the conditions under which the INS becomes unobservable, and these conditions are validated through numerical simulation. The main contributions of this paper are as follows, 1. Nonlinear observability analysis of the range assisted INS for quadrotor MAVs. 2. Theoretical derivation and numerical validation of unobservable conditions for three and two range cases. 3. Experimental validations of estimator performance.