Telecommunications-satellite orbit determination via television-signal range measurements

Experimental results from an attempt to perform communications satellite ranging with a normal TV link are reported. The trial involved inexpensive equipment and the satellite's broadband TV channel. A signal was broadcast to the satellite, which relayed the signal back to the station. A ranging formulation was defined, using successive signals to obtain 1.5-4 m one-way precision. A resolution of 10-20 nsec was obtained in measuring the propagation delay. The use of the technique with the Sirio satellite is described, demonstrating that only a few measurements per day were required. Orbital position could be fixed within a few thousandths of a degree of latitude and longitude with measurements only one out of every 12 days. Improvements in the measurements are predicted with better instrument calibration and equipment.