AUTONOMOUS NAVIGATION FOR THE NEW MILLENNIUM PROGRAM EARTH ORBITER 1 MISSION

The New Millennium Program's Earth Orbiter-1 (EO-1) spacecraft is scheduled for launch in May 1999. EO-1 will fly information with the Landsat 7 spacecraft to validate an advanced land imaging instrument for future Landsat missions. Autonomous navigation to support formation flying is an important new technology that will be flight validated on EO-1. Navigation here, is defined as the process of determining and controlling the orbit of a spacecraft. Orbit determination is provided by an onboard Global Positioning System (GPS) receiver/processor; while, a simple empirical approach has been developed to provide orbit control from within the Attitude Control System (ACS) architecture. Since autonomous orbit determination has been demonstrated before, the orbit control algorithms and their integration with the GPS determined orbits are the primary focus of this paper. Simulation results are presented that show the expected intervals between orbit control maneuvers.