Mars Exploration Using Self-Calibrating Pseudolite Arrays

摘要

Future Mars rover missions will require greatly en-hanced navigational capabilities over those possessed by Mars Pathfinder. The centimeter-level accuracy re-quire( l for these missions makes GPS a natural candi-date for any future integrated navigation system. Be-cause there are no GPS satellites around Mars, navi-gation will require the use of pseudolites. The Aerospace Robotics Lab at Stanforcl is develop-ing a new system called a Self-Calibrating Pseudolite Array (SCPA) to solve the problem of autonomously determining the locations of the pseudolites after de-ployment,. This is achieved through the use of GPS transceivers, capable of both sending and receiving GPS signals. Three such devices, together with a tech-nique called Inter-Transceiver Pseudoranging (ITP ), allow the rover to navigate across the planetary sur-face to approximately meter accuracy. Centimeter-level accuracy can be obtained by extending the ar-ray to a greater number of devices and using CDGPS techniques. This paper provides an overview of the capabilities of SCP.AS and the challenges associated with pseudolite operation on Mars. The methodology and algorithms associated with ITP are discussed, as well as the ex-pected error sources. Simulation results show the ob-servability of all states of interest for the array self-calibration.