PASADENA, Calif. — Analytical Graphics Inc. (AGI), in partnership with a Canadian company, announced May 23 that it has established the first commercial radar system capable of tracking objects in geostationary orbit and beyond.
AGI and Thoth Technology said they have set up a radar system on a 46-meter antenna at the Algonquin Radio Observatory in Ontario. The system is capable of tracking objects out to distances of 50,000 kilometers, and can detect objects about two meters across on GEO.
Tom Johnson, vice president of engineering at AGI, said his company long sought a radar capability to augment optical telescopes currently used to track satellites in GEO as part of its Commercial Space Operations Center, or ComSpOC, space situational awareness service.
“Telescopes have their own limitations. They only work at night and they only work when the weather is good,” he said in an interview. “It’s important to bring in other types of data.”
At the top of that list for other data is radar observations. “That becomes important for a lot of commercial players operating in GEO. It allows us to track them, but also GEO-crossing debris: objects that pass through the GEO belt that cause risk to the operators there,” he said.
Radar has typically been limited to low Earth orbit observations because of power requirements. AGI found a way around that by using the 46-meter antenna at Algonquin Radio Observatory, operated by Thoth Technology. They developed a C-band transmitter for use on the telescope, turning it into a radar with far greater gain than alternative systems.
Johnson said that combining the radar observations with existing optical observations of GEO belt objects improves the accuracy of positions of those objects to 150 meters, compared to 250 meters using optical observations alone. That gives customers greater assurance when dealing with potential conjunctions involving their objects. “They don’t have to be as concerned about closely spaced conjunctions because we have increased confidence in our orbit solutions,” he said.
Johnson said it should be possible to detect objects smaller than two meters with the radar. “It’s just a matter increasing the power level on the radar,” he said. “We want to get down to 20 centimeters or less.”
AGI is currently using the telescope to sweep across the GEO arc visible from the observatory every two weeks to build up data to demonstrate its capability to customers. In the future, more frequent monitoring is planned to be better able to track movements of satellites in the GEO belt, particularly those whose intent is unclear, like the Russian Luch satellite that in the past has drifted near commercial satellites in GEO.
The system is limited to observations of objects in medium Earth orbit, used by GPS satellites, out to about 50,000 kilometers. It is not useful for low Earth object objects because the antenna is so large it can’t move fast enough to track them, he said, but AGI is planning some experiments to pre-position the antenna to track a LEO spacecraft passing through its field of view.
The Algonquin Radio Observatory can observe the GEO belt from between 14 and 142 degrees west. Johnson said AGI is “actively” searching for additional locations to observe other parts of GEO. “We think this a model that we can replicate in other places around the world,” he said, such as Asia.
