Technical analysis of Starlink terminal data from Iran provides direct evidence of GPS spoofing deployed by authorities to degrade satellite internet services during the ongoing communications blackout, according to a report based on debug telemetry captured in January.

The analysis, compiled from official Starlink mobile application debug data, shows the terminal detected anomalous GPS signals and activated countermeasures, recording sustained 20% packet loss whilst the connection never stabilised during 24 minutes of operation, technology expert Nariman Gharib announced.

The terminal recorded 18 GPS satellites with valid lock but activated an "inhibitGps" flag, indicating the device's anti-spoofing algorithms detected that GPS signals, whilst present and strong, could not be trusted, according to the technical report.

"The combination of evidence suggests GPS spoofing (injection of fake signals) rather than simple jamming (signal blocking)," the analysis stated. If GPS was simply being jammed, the terminal would show invalid GPS status or very low satellite counts, rather than 18 satellites with valid lock but inhibited positioning.

The terminal showed pointing errors of approximately 1 to 1.2 degrees away from desired direction, whilst attitude uncertainty measured only 0.32 degrees, indicating the device was using fallback positioning methods less accurate than GPS, the report said.

After 24 minutes of operation, the terminal recorded zero seconds of stable connection, with the Extended Kalman Filter sensor fusion system taking 198 seconds to converge, significantly longer than typical performance, according to the data.

Sustained packet loss averaged 20% to 22% over five minutes, compared to the typical Starlink performance of less than 1% packet loss. Both uplink and downlink showed bandwidth restrictions, indicating that terminal- or network-imposed throughput limits were in place as a protective measure when operating in degraded mode.

The terminal successfully completed initial network entry, established control channels and received beam schedules, demonstrating basic connectivity was preserved despite electronic warfare conditions, the analysis showed.

Iran has maintained a near-total internet blackout since January 8 during protests that began on December 29. Opposition sources reported on January 10 that authorities are conducting house-to-house searches to confiscate Starlink equipment.

Exiled Crown Prince Reza Pahlavi reported on January 10 that simultaneous access to 80% of contacts using Starlink had been cut off, suggesting authorities are using tools to disrupt radio waves and GPS alongside internet cuts.

The technical findings demonstrate that GPS spoofing is an effective tactic to impair satellite internet service from broadband to barely usable, though not eliminate it entirely.

The terminal maintained connectivity but delivered severely degraded performance with sustained packet loss, restricted bandwidth and suboptimal beam pointing.