Geosynchronous satellites orbits from optical observations

An autonomous robotic system is developed for performing optical observations of geosynchronous (GEO) satellites, determination of their angular positions in the sky, and the improvement of their orbits. Each of the images, taken with a CCD-camera attached to the telescope, contains several exposures of the satellite together with the trails of the background stars. A new method is presented to determine the stars positions in the images, based on the rotational algorithm. The automatic processing of the CCD image taken over the night results in a number of the sequence of precise satellite angular coordinates. Using these coordinates as measurements, the orbit defined by the relevant NORAD TLE set -As a preliminary one, and an adequate dynamical model of the satellite orbital motion, an improved orbit can be obtained by the least-squares differential correction algorithm. In this way, the post-fit angular positions of AMOS-2 and -3 GEO satellites were determined with the accuracy of about 0".5 (< 100 meters). Incorporating the radar ranging measurements provides insignificant improvement to the angular position estimates.