Finite-time Stable Pose Estimation for Unmanned Vehicles in GNSS-denied Environments using an Onboard Camera

This work presents a finite-time stable pose estimation scheme for autonomous aerospace vehicles undergoing rotational and translational motion in three dimensions, using measurements from onboard optical sensors. The estimation scheme is designed as an observer for the pose (position and orientation) and velocities of a rigid body in real-time and is obtained through a Lyapunov analysis that shows its stability in finite time. This observer is designed directly on the Lie group of rigid body motions, SE(3), and does not require a dynamics model for the vehicle to update the state estimates. These features enable it to estimate arbitrary rotational and translational motions without encountering singularities or the unwinding phenomenon, and be readily applied to a vehicle with any sensor-actuator configuration without requiring extensive re-tuning. The proposed estimator is discretized using the framework of geometric mechanics for numerical implementations. Numerical simulation results validate the stability of this pose estimation scheme.