AAS 98-115

SINGLE TRACK COVARIANCE FOR SPACE SURVEILLANCE NETWORK SENSORS

K. T. Alfriend - Texas A&M University; F. Hoots, R. A. Glover, R. G. France - GRC International

Abstract

When USSPACECOM updates the orbital elements of objects in the space catalog, a covariance at epoch is also obtained. This covariance does not provide an accurate estimate of the position error at times beyond epoch. In this paper a study is made of the accuracy and distribution of the covariance resulting from single tracks of SSN sensors. A total 31,119 tracks of 31 satellites in altitudes from 500-1000 kilometers were used in the analysis. The prediction intervals were 0.25 - 2.0 orbits. The results show that the orbit errors are approximately Gaussian and the covariance for single tracks is a good estimator of orbit error.

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