Comparison of optical and radar tracking for catalog maintenance

This paper addresses the use of optical systems for updating the state or orbital elements of satellites in low Earth orbit. The angular accuracy of optical systems, their low cost and capability to operate autonomously, and to see low altitude satellites during the day make them a potential valuable asset for assisting in the catalog maintenance of low altitude satellites. In this paper a comparison is made of radar and optical systems for providing updates of the orbital elements for catalog maintenance. An analytic model assuming a circular orbit with a sensor on a non-rotating Earth is developed and comparisons made between radar and optical systems. Results are obtained for an orbit comparable to GFO, a LEO satellite at 780 km for which results have been previously published.