Trajectory-keeping in satellite formation flying via robust periodic learning control

This paper proposes an iterative learning control (ILC) scheme to ensure trajectory-keeping in satellite formation flying. Since satellites rotate the earth periodically, position-dependent disturbances can be considered time-periodic disturbances. This observation motivates the idea of repetitively compensating for external disturbances such as solar radiation, magnetic field, air drag, and gravity forces in an iterative, orbit-to-orbit manner. It is shown that robust ILC can be effectively utilized for satellite trajectory tracking, thus enabling time-variant formation flying between the leader-and follower-satellites. The validity of the results is illustrated through computational simulations. Copyright (C) 2009 John Wiley & Sons, Ltd.