Guidance for Spacecraft Docking incorporating Model Uncertainties: A Linear Quadratic Tracking Approach

Abstract

A robust guidance algorithm for docking with a target satellite in Low Earth Orbit is proposed in this work. An optimal control logic based design minimizes the fuel consumption thereby maximising the payload. A linear quadratic integral controller that can tackle model error as well as deviations from desired initial conditions that must be attained before initiation of docking procedures is designed. Practical considerations such as thruster capability is accounted for. An approach facilitating soft docking as well as one which gives non oscillatory results are considered separately and compared. The designed controller is tested against a variety of initial conditions and disturbances. The guidance algorithm can easily be interfaced with machine friendly languages like C or Python.