Summary of orbit computations from laser range observations of LAGEOS, Starlette, GEOS 3 and SEASAT

How the spatial, temporal and geographical distribution of laser range measurements, and the selection of satellite and perturbation force model, affect orbital and parameter solutions was investigated. Satellite perturbation due to the Earth gravity field, atmospheric drag, solar and lunar attraction, direct solar radiation pressure and solid Earth tides were considered. Dynamic model errors (not laser range measurement precision) limit the accuracy of a long arc orbital solution. Tailored gravity models are more accurate than GEM-9 or GEM-10B. For low-altitude satellites with large appendages, accurate orbit determination requires precise modeling of the time-dependent variation of the satellite cross sectional area. Density fluctuations due to short period solar and geomagnetic disturbances are modeled relatively poorly. Multiple drag coefficient models eliminate orbital effects of these model errors.