Starlink shuts down its GPS-style cheat code. Researchers may unlock it anyway.

Source: Ars Technica

Background

In 2021, a team led by Zak Kassas, director of the Autonomous Systems Perception, Intelligence, and Navigation (ASPIN) Laboratory at The Ohio State University, showed how electronically eavesdropping on signals from six Starlink satellites could pinpoint locations on Earth to within 8 meters of accuracy—although that required 13 minutes of tracking rather than delivering instantaneous results.

Challenges

Starlink continuously optimizes its primary satellite‑Internet service by turning beams on and off or switching beams as fast‑moving satellites communicate with many different users. This creates unpredictable jumps in the signal‑timing estimates that the researchers rely upon to calculate positioning data.

Methodology

To address these challenges, Kassas and his colleagues:

• Use Doppler measurements of signal‑frequency changes that reflect satellite motion relative to the receiver.
• Apply software algorithms to correct timing errors.
• Deploy phased‑array antennas capable of communicating with one or two satellites at a time, combined with low‑gain, omnidirectional antennas that can capture signals from nearly ten satellites simultaneously.

By 2025, the researchers demonstrated that harnessing signals from an average of three Starlink satellites could deliver positioning results to within 2 meters of accuracy in just 20 seconds.

Broader Applicability

The eavesdropping strategy is not limited to Starlink. The team has also exploited signals from Orbcomm, Iridium, OneWeb, NOAA, and the dedicated PNT constellation Xona. “I’m not really married to Starlink—I love them all,” Kassas said.

The alternative navigation solution has been demonstrated with ground vehicles, a high‑altitude balloon, and a drone. A recent experiment showed that exploiting signals from both Starlink and OneWeb satellites could improve ship navigation accuracy off the west coast of Greenland in the Arctic, suggesting the technique could work nearly anywhere on Earth.

Implications

All this suggests that new GPS alternatives may arrive sooner than expected, whether they come directly from Starlink or from third parties. Kassas and his team have already licensed their technology to several organizations. “I think people are hungry and hurting in the absence of GPS or GNSS, and they want these solutions,” Kassas told Ars.