For example, an individual spacecraft with healthy batteries may trade off time in eclipse for fuel savings. Since individual spacecraft in a large diameter array experience significantly different gravity gradients, nonlinear orbital dynamics and relative motion models are used. Relative position measurements are made from routine satellite cross-link communication signals. As in MANS, a deterministic solution is used to initialize and backup Kalman filter state estimates. Individual spacecraft inertial position, velocity and attitude state as well as spacecraft relative position and velocity in an orbiting array coordinate system are estimated with an extended Kalman filter.
State information is shared among spacecraft in short cross-link messages.
Continuous link is not necessary. The feedback control loop is closed when the spacecraft selects a trajectory, implements the specified thrust profile, and passes thrust impulse information back to the Kalman filter propagator. Closed loop simulation results are not yet available. The research has significance by extending current thrusts in fully autonomous operations to a unified large diameter array of distributive controlled spacecraft.