A Test of Autonomous Navigation Using Near Laser Rangefinder Data

Abstract

Ground-based navigation of spacecraft missions currently involves intensive manpower and inherent downlink-uplink time delays. It would be beneficial to have autonomous navigation to determine the flight path in real-time, compute maneuvers, and control science instrument pointing during the orbiting phase of a mission. Laser altimetry is an accurate data type that requires neither the two-way communication of Doppler nor the human identification of landmarks that optical data currently requires. The NEAR mission has offered the first opportunity to compare navigation by laser altimetry to navigation using the standard data types. The test would be whether laser altimetry provides sufficient information to perform orbit determination within mission requirements.

To assess the effectiveness of laser altimetry-based navigation, questions of what constitutes an effective estimation strategy, the accuracy of spacecraft position and velocity estimates, the required accuracy of shape and gravity models, the speed of recovery from maneuver errors, and the accuracy with which position may be mapped (predicted), are examined.