After SpaceX declined to continue researching Starlink as a possible military alternative to GPS in 2020, a group of researchers found a way to do it without the help of Elon Musk — or his company that created the constellation of internet satellites.
Professor Todd Humphreys is a University of Texas researcher who has been leading a group of scientists in the reverse-engineering of signals from the satellite constellation. This was done with the hopes of creating a new navigational system that could operate independently from the Global Positioning System. MIT Technology Review reported.
You can find out more at non-peer-reviewed study,Humphreys claims that Starlink’s signals have been characterized in detail by the group, without accessing its encryption or any user data obtained from satellites.
Humphreys stated that “The Starlink signal is a highly guarded secret.” MIT Technology Review.“Even though SpaceX was more cooperative in the early discussions, they didn’t disclose any signal structure to us. We had to begin from scratch and build basically a radio telescope to listen to their signals.
Starting with a Starlink unit programmed to transmit high-definition YouTube videos of Spanish tennis player Rafael Nadal, the group began tracking the satellite’s synchronization sequences and detected their patterns of transmission — about four sequences every millisecond. These sequences — repeating patterns of signals beamed down to Earth by the satellite — help receivers coordinate with them, leaving clues to the satellite’s distance and velocity.
Humphreys said that earthbound receivers can use the timing of satellite signals and information publicly available about the orbit to calculate distances and estimate a location within 30 m. MIT Technology Review.Geolocating capabilities can be improved by tweaking.
The discovery, while a potential breakthrough for geolocation services, also revealed a possible security concern about Starlink signals — which are currently key to Keep Ukrainian communication services operating as Russia has invaded the country — if used as a navigation system.
Mark Psiaki (an aerospace professor at Virginia Tech who is also a GPS expert) said, “Humphreys did a huge service to navigation community identifying those sequences.” MIT Technology Review. “But any navigation system working on open-source sequences could definitely be spoofed, because everyone will know how to spot those signals and create fake ones.”
Starlink is an integral part wartime communication in Ukraine, so much so that recent outages were called “Starlink”.Catastrophic” By officials. Musk Tweet this week Russia is “actively working” to destroy the satellites, but Humphreys’ discovery — that the signals are predictable and replicable — highlights the possibility for intentional disruption of Starlink.
Humphreys stated that Ukraine and its allies in NATO are becoming more dependent on Starlink. MIT Technology Review. Starlink security has many million of users, which includes its resistance to jamming. Understanding the signal structure is key to assessing security.
Insider reached out to Musk, SpaceX and Humphreys but they did not immediately reply.
