Output feedback elliptical orbital rendezvous via state-dependent Riccati differential equations

This article studies spacecraft rendezvous with the target spacecraft in an arbitrary elliptical orbit. Based on the linearised Tschauner-Hempel equations, state-dependent Riccati differential equation (RDE)-based approaches are proposed to solve the problem. An observer-based output feedback controller is established. To implement the proposed controller, only some forward-type RDEs need to be integrated online, indicating that the controllers can be implemented online as long as some positive-definite initial conditions are given. Moreover, it is shown analytically that the closed-loop system under the proposed feedback controller is exponentially asymptotically stable. Numerical examples show the effectiveness of the proposed approach.