REAL-TIME GPS ATTITUDE DETERMINATION SYSTEM BASED ON EPOCH-BY-EPOCH™ TECHNOLOGY

Abstract

There are many civilian and military applications requiring precise attitude determination. Geodetics Inc. has demonstrated high-accuracy GPS attitude solutions using their Epoch-by- Epoch™ (EBE) technology. EBE technology provides computational algorithms for instantaneous differential GPS processing of raw GPS measurement data (pseudorange and carrier phase). One of the most significant advantages of EBE technology over conventional GPS Real-Time Kinematic (RTK) algorithms is in its instantaneous initialization and reinitialization capability. This capability eliminates re-initialization delays due to losses-oflock, such as occur during high-dynamic maneuvers. This paper provides empirical data that was gathered during a test program, sponsored by Eglin Air Force Base, to assess the performance in real time of EBE technology as it applies to attitude determination. Using simulated data from a high-dynamic (9’g) maneuver, EBE yielded real-time attitude with accuracy better than one tenth of a degree (0.038 - 0.083 degrees, one standard deviation), utilizing geodetic quality GPS receivers operating in dual- or single-frequency mode with antenna separation of 2 meters. GPS geodetic receivers with only single frequency capability yielded attitude with accuracy of between 0.044 - 0.176 degrees after 1.3% - 2.5% of the solutions were rejected as data outliers.