  This paper presents a new algorithm for autonomous multitarget tracking of
resident space objects using optical angles-only measurements from a spaceborne
observer. To enable autonomous angles-only navigation of spacecraft swarms, an
observer must be able to identify and track multiple known or unknown target
space objects in view, without reliance on a-priori relative orbit knowledge.
Extremely high assignment precision is necessary with low measurement
frequencies and limited computational resources. The new "Spacecraft
Angles-only MUltitarget tracking System" (SAMUS) algorithm has been developed
to meet these objectives and constraints. It combines domain-specific modeling
of target kinematics with multi-hypothesis techniques to autonomously track
multiple unknown targets using only sequential camera images. A measurement
transform ensures that target motion in the observer reference frame follows
consistent parametric models; curve fitting is used to predict track behavior;
and kinematically-derived track gating and scoring criteria are applied to
improve the efficiency and accuracy of the multi-hypothesis approach.
Monte-Carlo testing with high-fidelity simulations demonstrates close to 100%
measurement assignment precision and strong recall across a range of
multi-spacecraft formations, in both near-circular and eccentric orbits.
Tracking is maintained in the presence of eclipse periods, significant
measurement noise, and partially known swarm maneuvers. A comparison to other
tracking algorithms reveals strong advantages in precision, robustness and
computation time, crucial for spaceborne angles-only navigation.
