CONTROL AND MULTI-OBJECTIVE OPTIMISATION OF A CONSTELLATION OF SPACECRAFT FLYING IN ELLIPTICAL ORBITS

摘要

A formation of four spacecraft flying in a tetrahedron formation is considered and a mathematical model of the system is developed. For the application of using the satellites for the global positioning and navigation, the non-linear task of thrust control is formulated for the satellite constellation. This non-linear multi-objective optimization problem is solved in view of the limited-thrust constraints with the objective to maximize the tetrahedron volume for increased mission efficiency. To solve the optimization problem, DIRECT computer code is used. This is based on the direct transcription of the continuous problem to a discrete nonlinear programming problem. Analysis of results on the satellite trajectories and minimized thrust histories is presented and the simulated optimized constellation missions are simulated in Virtual Reality in inertial, Earth and relative to satellites local coordinate systems.