Benefits of a Geosynchronous Orbit (GEO) Observation Point for Orbit Determination

Determining orbits of unknown objects is a fundamental space situational awareness activity. The U.S. Space Surveillance Network SSN currently relies on ground-based radars, optical telescopes, and the Space Based Space Surveillance SBSS System. The SBSS system overcomes many of the pitfalls of optical ground-based systems like limited observation times e.g. weather and time of day and measurement uncertainty from atmospheric effects. However, the SBSS satellite is in a low earth orbit 630 km, sun synchronous, and must look up for GEO objects. This paper analyzes the potential benefits of a GEO observation point for performing metric observations that are combined with ground-based data. Several different scenarios are considered to quantify the reduction in orbit uncertainty from these types of observations. All results are derived using an Extended Kalman filter EKF to process the observations. Orbital uncertainties are expressed in terms of the error covariance.