Mystery GPS jammer in Iran becomes test for NASA satellites’ capabilities

Source: Ars Technica

Overview

NASA satellites designed to observe cyclone wind speeds and collapsing ice sheets have also proven capable of identifying the approximate locations of GPS jammers. This capability could help monitor high‑risk areas for aircraft and ships navigating the growing prevalence of GPS interference worldwide.

Two different NASA satellite systems were able to locate a known but mysterious GPS jammer within several kilometres of its position in Iran, according to an experiment by Sean Gorman, CEO and co‑founder of the location‑based technology company Zephr.xyz. The findings were detailed in GPS World — see the full article here. Such jammers use strong signals to overpower the weaker radio signals coming from US‑operated GPS satellites and other global navigation satellite systems.

“These NASA satellites cannot perform near‑real‑time monitoring or pinpoint the exact location of GPS jammers,” said Clara Chew, principal scientist and lead of the GNSS systems and data team at Muon Space. “Identifying the approximate locations of GPS jammers could potentially be helpful for flight planning or for indicating high‑risk areas for maritime shipping.”

NASA Satellite Systems Capable of GPS Jammer Localization

Cyclone Global Navigation Satellite System (CYGNSS)

The Cyclone Global Navigation Satellite System (CYGNSS) consists of eight microsatellites that detect GPS signals reflected from ocean surfaces to measure wind speeds within the eyewalls of hurricanes, tropical cyclones, and typhoons. When an Earth‑based jammer is active, it creates a huge footprint in the reflected GPS signals that can appear hundreds of kilometres from the jammer’s location. As Gorman wrote, “CYGNSS sees the jammer’s effect on reflected GPS signals, offering an indirect measurement spread across hundreds of specular reflection points.”

NASA‑ISRO Synthetic Aperture Radar (NISAR)

The NASA‑ISRO Synthetic Aperture Radar (NISAR) mission typically uses radar imaging to continually map and track changes across the Earth’s surface, including earthquakes, tsunamis, volcanoes, and ice‑sheet collapses. GPS jammer emissions generate streaks in the NISAR radar imagery that run perpendicular to the satellite’s flight direction. Each streak “encodes the jammer’s direction relative to the satellite’s ground track,” allowing a more precise, though narrow, measurement of the jammer’s location. Gorman noted, “NISAR sees the jammer’s emissions directly in its own receiver, which is a more precise measurement, but only along the satellite’s narrow ground track.”

Potential Applications

While the current methodology does not provide near‑real‑time or pinpoint accuracy, the ability to approximate jammer locations from space offers valuable situational awareness. This information could be integrated into flight‑planning tools and maritime navigation systems to flag high‑risk zones, thereby enhancing safety for aircraft and ships operating in regions affected by GPS interference.