A Direct Multiple Shooting Method for Initial Satellite Orb it Determination

After a satellite has been launched, the determination of it s initial orbit is the primary question to be answered by mission control in order to prepare for high precision orbit determination and orbital transfers. For this purpose, tracking measurements performed by ground st ations are used and parameters are determined by solving a parameter estimation problem. We suggest to use the direct multiple shooting approach for the solution of this problem. We develop a tailored method calle d "analytical projection" for the generation of reasonable initial guesses. As a test scenario for our method, w e use operational tracking data of the ARTEMIS satellite, where the actual satellite trajectory differedsignificantly from the intended trajectory. A comparison to the widely employed direct single shooting method sho ws a significant improvement of the convergence behaviour.