Laser Communication Systems for Geolocation and Attitude Determination

The optical communication links between various orbiting satellites can serve as the cornerstone of an accurate attitude and geo-referencing scheme when 2 or more vehicles are engaged in laser communication. To date, most research studies into determining relative attitudes and positions between vehicles have involved using the global positioning system (GPS) which restricts the spacecraft formation to near-Earth applications. An application of GPS-like technology to a deep space mission has been proposed but this requires extensive hardware development and is subject to the generic GPS performance-limiting effects. The objective of this work is to provide a novel, reliable, and autonomous relative attitude and position estimation system that is independent of any external systems. The proposed work presents an extended Kalman filter (EKF) formulation to estimate the relative attitude and position of 2 or more platforms engaged in communication using Line of Sight (LOS) observations to determine absolute yaw, pitch and roll vehicle information. Platform absolute position will be determined using time of flight techniques embedded in the transmitted LOS. In addition, terminal to terminal same platform attitude will be determined via metrology and algorithm development.