LAUSR

Abstract Nonlinear control for satellite formations is a requirement for challenging missions with large intersatellite distances where spherical gravitational nonlinearities and differential disturbances are significant. This paper presents the design of a formation flying orbit control system for low Earth orbit (LEO) satellites based on the State-Dependent Riccati Equation (SDRE) control approach. An exact nonlinear differential J2 perturbation model is used for the relative orbital dynamics, and SDRE tracking is posed as an error regulation problem. Two State-Dependent Coefficient (SDC) matrices are formulated that avoid singularities such that the controller does not suffer from chattering effects. The additional degree of freedom associated with the SDC parameterizations is exploited using a weighting parameter to tune the control performance. Stable solutions in the domain of interest are obtained and results for thrust and time of formation acquisition for the proposed SDRE controller are presented.