NASA Satellites Tested by Mystery GPS Jammer in Iran
▼ Summary
– NASA satellites designed for cyclone wind speeds and ice sheet mapping can also locate GPS jammers within several kilometers, as demonstrated by an experiment in Iran.
– The CYGNSS satellite system detects jammers by observing their effect on reflected GPS signals, creating a footprint hundreds of kilometers from the jammer.
– The NISAR satellite system identifies jammers through streaks in radar imagery that indicate the jammer’s direction relative to the satellite’s path.
– These satellite systems cannot provide near-real-time monitoring or exact jammer locations, but can help identify high-risk areas for flight planning and maritime shipping.
– CYGNSS offers indirect, wide-area measurements of jammer effects, while NISAR provides more precise but narrow-track direct emissions detection.
NASA satellites built to track hurricane wind speeds and monitor collapsing polar ice sheets have unexpectedly proven capable of detecting the rough location of GPS jammers. This capability could help identify high-risk zones for aircraft and maritime vessels as GPS interference becomes more frequent around the globe.
In a recent experiment detailed in GPS World, Sean Gorman, CEO and cofounder of the location-tech firm Zephr.xyz, demonstrated how two distinct NASA satellite systems successfully located a known but unidentified GPS jammer in Iran within a range of several kilometers. These jammers operate by broadcasting powerful signals that drown out the weaker transmissions from U. S. GPS satellites and other global navigation networks.
Clara Chew, principal scientist and lead of the GNSS systems and data team at Muon Space in California, was not involved in the study but noted that while these satellites cannot provide near-real-time monitoring or pinpoint the exact coordinates of a jammer, they do offer useful approximations. “It could potentially be helpful for flight planning,” Chew told Ars, “or for indicating high risk areas for maritime shipping.”
One of the systems, the Cyclone Global Navigation Satellite System (CYGNSS), consists of eight microsatellites that detect GPS signals bouncing off ocean surfaces to gauge wind speeds inside hurricanes, tropical cyclones, and typhoons. When a ground-based jammer activates, it leaves a massive signature in the reflected GPS data, visible hundreds of kilometers from the jammer’s actual location.
The other system, the NASA-ISRO Synthetic Aperture Radar (NISAR), typically uses radar to continuously map Earth’s surface and track changes from earthquakes, tsunamis, volcanoes, and ice sheet collapses. GPS jammer emissions, however, appear as streaks in NISAR’s radar imagery, running perpendicular to the satellite’s flight path. As Gorman explained in his article, “each streak encodes the jammer’s direction relative to the satellite’s ground track.”
“CYGNSS sees the jammer’s effect on reflected GPS signals, offering an indirect measurement spread across hundreds of specular reflection points,” Gorman wrote. “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.”
(Source: Ars Technica)