Assessment of Single Satellite-based Lunar Positioning for the NASA Endurance Mission

To answer key questions regarding the origin of the Solar System, the NASA Jet Propulsion Laboratory (JPL) has developed the Endurance rover mission concept to explore and collect samples from the Moon’s oldest impact basin, the South Pole–Aitken. The Endurance rover is targeted to launch in 2030 and will autonomously traverse a total of 2000 km across the basin, periodically stopping for sample collection at sites of scientific interest. To maintain its planned trajectory and precisely geo-tag each sample collection for scientific studies, the rover will require precise, absolute localization.The Endurance mission concept will additionally employ the Lunar Pathfinder satellite for communication relays. Given the Lunar Pathfinder is capable of carrying a radionavigation payload, we assess the achievable position estimation accuracy for the Endurance rover using two-way ranging measurements from the Lunar Pathfinder. We investigate two state estimation frameworks for this scenario. The first is a weighted batch filter which accumulates measurements over time to provide a global localization fix. To reduce computational demands during localization, we also consider a combined weighted batch filter and extended Kalman Filter scheme.We evaluate the performance of these frameworks at key waypoints along the rover’s planned trajectory. Our simulation models realistic received signal carrier-to-noise density ratio by modeling the antenna gain pattern of the lunar satellite and surface rover’s onboard antenna. We further model two-way ranging measurement accuracy, which includes effects of satellite ephemeris uncertainty, residual errors in the two-way relay delay, as well as the rover’s onboard signal tracking errors. Through our simulation, we demonstrate that our approach achieves meter-level accuracy with a convergence time of less than 4 hours with only a single satellite, the Lunar Pathfinder, in view.