AAS 99-175

Determination and Modeling of Error Densities in Ephemeris Prediction

J.P. Jones, M. Beckerman

Oak Ridge National Laboratory, TN


We determined the distributions of error in position predicted by a Special Perturbations orbit propagator for a population of 14 low-earth orbiting satellites. Errors in the along-track, radial and cross-track directions were extracted by aligning and combining 72-hour ephemerides calculated sequentially for periods of time spanning several months for each satellite. The along-track errors dominate, and together with the radial increase uniformly in time. The growth rate for the along-track errors is correlated with the decay rate of the semi-major axis and the growth rate for the radial errors is correlated with the eccentricity.