ERS-1 orbit determination from laser, TRANET, and PRARE tracking data

An error model for ERS-1 orbit determination was derived and was used for covariance analyses of 3-day, 2-revolution, and 15-min data arcs. For the 3-day and 2-revolution arcs, laser range and TRANET 2 range rate tracking concepts were studied. Laser and PRARE range tracking concepts were studied using a 15-min arc. To enable the computation of accurate orbits a tailored gravity model should be developed from ERS-1 tracking data acquired during the first months in orbit. For the 3-day arc the full 14-stations laser network leads to essentially the same orbit accuracy as the 45-stations TRANET network. For the error model considered a reduction of the number of tracking stations to 5 hardly deteriorates the radial orbit accuracy. To derive accurate dynamic models a dense tracking network is required during the initial mission phase.