Starlink keeps growing, and so do its capabilities. Lately, even people outside of SpaceX have even been developing capabilities for it. A team of researchers from the Ohio State University (OSU) and the University of California Irvine (UCI) has developed a way to use Starlinks networked satellites as a basic navigation tool.
The Global Position System (GPS) has been in use for decades at this point and forms the backbone of everything from car’s automated driving systems to running watches. However, it has some weaknesses. Since the system is so well known, it has been susceptible to attacks, which have caused problems ranging from overriding the flight path of civilian and military drones to hijacking the autopilot feature of Tesla’s cars.
There are already alternatives to GPS, but Dr. Zak Kassas and his team decided to see if he could use a different technique that was never expressly intended for navigational purposes – Starlink. Currently, Starlink has approximately 1,700 satellites orbiting the Earth attempting to provide broadband internet anywhere in the world. SpaceX, the company responsible for the program, expects to launch 40,000 satellites to support the network. Each of these satellites is also in a much lower orbit than existing GPS satellites, making them easier to communicate with.
Starlink satellites also have identifying metadata that allows ground controllers to differentiate between signals coming from different satellites. Each satellite also has a distinct orbital path that can be used as a positional reference. Using signal strength, metadata from the satellites themselves, and estimates of the orbital position of those satellites, researchers in Dr. Kassas’s lab were able to globally pinpoint an antenna receiver within about 7.7 meters of its actual location.
This isn’t quite the same accuracy level as GPS, which can vary between 0.3 and 5 meters in accuracy. However, the technique utilized only six Starlink satellites for its positioning, and with the increasing number of satellites in orbit, Dr. Kassas expects that accuracy level to increase dramatically.
Nor is Starlink the only system the researchers have used this technique on. They’ve used other low-Earth orbit satellite systems to locate objects within 23 meters and even land-based transceivers to help locate high-altitude aircraft.
Even more surprisingly, the researchers did all this work without any assistance from SpaceX at all. They simply decoded the metadata from each satellite, not the messages themselves, which hold encoded internet traffic. However, it does beg the question, how much more work would be necessary to completely decode the messages rather than just the metadata, thereby compromising Starlink’s network integrity.
For now, the OSU / UCI researchers have no intention to find out. Their work is focused entirely on getting useful navigational data out of a new infrastructure asset that wasn’t designed for it. If their accuracy increases to the expected level, then maybe Starlink, which was never intended as a navigational tool, can eventually fill in for GPS in a pinch.
OSU – SpaceX satellite signals used like GPS to pinpoint location on Earth
Ion – Exploiting Starlink Signals for Navigation: First Results
Ars Technica – Researchers use Starlink satellites to pinpoint location, similar to GPS
UT – How Will Starlink’s Packet Routing Work?
Artist concept of Starlink constellation.
Credit – Getty Images