Pinpointing GNSS Interference from Low Earth Orbit

Global Navigation Satellite Systems (GNSS) such as GPS provide meter-accurate positioning while offering global accessibility and all-weather, radio-silent operation. However, GNSS is fragile: its service is easily denied by jammers or deceived by spoofers. GNSS signals are especially vulnerable to jamming because they are extremely weak: near the surface of Earth, they have no more flux density than light received from a 50W bulb at a distance of 2,000km. Furthermore, GNSS jammers are easily accessible and low cost, threatening GNSS-reliant systems. Without proper countermeasures, victim GNSS receivers can be rendered useless.

The civilian maritime and airline industries frequently encounter GNSS jamming and spoofing. Corrupted Automatic Identification System (AIS) and Automatic Dependent Surveillance-Broadcast (ADS-B) messages from surface vessels and aircraft are often reported. Irregularities in AIS and ADS-B reports are often indicative of GNSS interference. Geolocation of GNSS jammers with ADS-B data is possible, but only coarse jammer position estimates are achievable.

A first step to developing situational awareness and eliminating GNSS interference is geolocating the emitters involved. 

Read more in Inside GNSS article.

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