RELATIVE NAVIGATION FOR SATELLITES IN CLOSE PROXIMITY USING ANGLES-ONLY OBSERVATIONS

Relative navigation using angles-only observations is explored in this research. Previous work has shown that the unique relative orbit of a deputy satellite cannot be found using angles-only camera measurements from the chief satellite when a linear model of relative motion is used, due to a lack of observability. This work examines the possibility of partial observability, which in this case consists of a basis vector that corresponds to a family of relative orbits. An initial orbit determination (IOD) method is introduced that uses 3 Line-Of-Sight (LOS) measurements and provides an initial guess for the basis vector. This guess is differentially corrected with a batch estimator that takes in a full set of LOS measurements to hone in on a converged solution for the basis vector.