Autonomous navigation of spacecraft formations for asteroid exploration

This paper presents an autonomous multi-sensor navigation approach for a formation of spacecraft flying in the proximity of a near Earth asteroid.Each spacecraft embarks a different combination of high resolution cameras, attitude sensors and LIDAR to estimate the stateof each spacecraft in the formation. The work investigates the combination of measurements coming from multiple heterogeneous sensors and nonlinear sequential filtering technique to enable a formation to autonomously navigate in the proximity of asteroids. This work is divided into two parts. Firstly, each spacecraft employs an Unscented Kalman Filter to data fuse multi-sensor measurements of the relative position of the spacecraft with respect to the asteroid possibly combined with measurements of the relative position of the spacecraft within the formation, thus determining position and velocity of each member. Secondly, the combination of the autonomous orbit determination with absolute measurements is considered. Absolute measurements include range and range rate measurements from the ground station and pseudo range rate measurements from on board Sun Doppler shift sensor. The combination of the two sets of measurements and state estimations from on-board and ground provides an interesting mean to accurately determine the orbit of asteroids