Improved angular observations in geosynchronous orbit determination

How improved angular observations can aid in the determination of satellite position and velocity in the geosynchronous orbit regime is studied. Raven, a new, automated, low-cost sensor being tested by the U.S. Air Force Research Laboratory, allows for angular observations of satellites to be made with a standard deviation of approximately 1 arc-s (which maps into approximately 170 m at geosynchronous altitude); this is an order of magnitude improvement over traditional angular observation techniques. Simulation studies are undertaken to show how these angular observations can be used in the orbit determination process both as the only tracking data source and as a supplement to other tracking data sources, such as radio transponder ranges. Parameters varied in the simulation studies include the number of observing stations, the density of the optical observations, and the number of nights of optical tracking. The studies indicate that including the improved angular observations with traditional high-accuracy range observations produces a considerable improvement in orbit determination accuracy over the range observations alone. The studies also indicate that single site geosynchronous orbit determination is an attractive alternative when combining improved angular and high-accuracy range observations.