Pose observers for Unmanned Air Vehicles

This paper addresses the design and discrete time implementation of nonlinear observers for the estimation of position and attitude with application to Unmanned Air Vehicles. A continuous time nonlinear observer on SE(3) is derived, that uses inertial and ranges measurements. The estimation errors are shown to converge exponentially fast to the desired equilibrium points in the presence of bias in the rate gyros. An observer discrete time implementation is proposed that resorts to recent geometric numeric integration results suitable for solving ODEs on SO(3). Simulation results are presented to assess the performance of the continuous time observer and of the discrete time implementation. The estimation results in the presence of noise in the inertial and range measurements are also analyzed.