Meter-level orbit determination of geosynchronous satellites by an economical tracking system

Covariance analyses to study the performance of a proposed high precision and low cost geosynchronous satellites tracking system are presented. The tracking systems main components are one TDRS, a near-by geosynchronous satellite, 4-5 automatic ground stations, and a Very Long Baseline Interferometric (VLBI) system. The automated ground station provides doubly differenced ranging measurements without precision clock. The VLBI system consists of 4 one meter antennas positioned on orthogonal 6000 km baselines and uses a GPS signal for clock synchronization. Based on the anticipated characteristics of the 1990 era VLBI system, doubly differenced ranging and dynamic model, a factor of 20 or better improvement can be expected in the TDRSS orbit determination accuracy. This would make the satellite-based delta-VLBI deep space navigation system more attractive than the other systems which have been proposed.