Autonomous interplanetary orbit determination using satellite-to-satellite tracking

A new method of interplanetary orbit determination is described that uses only scalar satellite-to-satellite observations such as crosslink range to estimate the orbits of all of the participating spacecraft simultaneously. This method, called liaison navigation, does not work in the two-body problem or for constellations in low Earth orbits in which two-body dynamics dominate. If the constellation is strongly affected by a third body such as the moon, the gravitational effect of the third body can make all of the spacecraft states observable. In the three-body problem, spacecraft in the vicinity of the L-1 and L-2 Lagrange points experience significant accelerations due to both of the primary bodies, and these are ideal locations for investigating the feasibility of liaison navigation. Covariance analysis is used to estimate the accuracy of liaison navigation for spacecraft in Earth-moon and sun-Earth halo orbits generated in the circular restricted three-body problem. With only data noise, the estimation accuracy for the spacecraft positions in some configurations is excellent. In addition, a range bias is successfully estimated, along with the satellite states. Principles of constellation design that lead to more accurate liaison navigation estimates are described, along with techniques for reducing the fit-span length.