Orbit Determination Using Flash Lidar Around Small Bodies

Abstract

This paper investigates the feasibility of relative navigation in proximity to small bodies using only flash light detection and ranging (lidar) data. A flash lidar returns a three-dimensional point cloud of its field of view and can be thought of as an elevation map in which each pixel returns a range. When using the current state of the art of two-dimensional optical images for relative navigation, an iteration process occurs between the optical navigation image correlation and orbit determination that typically must be performed on the ground. This paper presents a feasible measurement alternative to optical navigation that removes this iteration process and therefore adds potential to performing orbit determination onboard the spacecraft, increasing its navigation autonomy. This study includes an analytical derivation of the information content of a lidar beam, orbit determination simulations of terminator orbits about the asteroids Itokawa and Bennu, and an equivalent optical navigation simulation for comparison. A Monte Carlo robustness simulation was also performed as well as an orbit determination simulation on a descent orbit around Itokawa. These simulations simplified the relative navigation process and performed as good or better than corresponding optical navigation simulations.