Self-contained autonomous navigation system for deep space missions

摘要

A new type of autonomous navigation ystem is proposed here for deep space missions. It uses the sun as the reference body and determiens the spacecraft orbit based on observations made on the sun using onboard instruments. Two types of observation data, the direction of the spacecraft relative to the sun as a function of time and the optical Doppler shift due to the motion of the spacecraft relative to the sun, can be used for the spacecraft orbit determination. Unlike the ground-based system, this new system does not rely on the Deep Space Network and has the potential to guide the spacecraft into the deeper space. Also presented is a conceptual design of a dual imaging system which functions as a sun imager taking images of the sun against star backgrounds during the cruise phase and as a regular optical imager taking pictures of the targeting planetary body during the approaching phase. While the use of Doppler data in orbit determination is well known, it is shown here with detailed theoretical proof that the direction data alone can also completely determine the spacecraft orbit.