GPS is Everywhere
Most of us don’t think of GPS on a daily basis even though the technology has quickly become a quiet necessity in our lives. A vast majority of us walk around with an active GPS receiver in our pocket. The modern cellphone has been equipped with a tiny GPS receiver ever since the FCC mandated its use for location by rescue workers and 911 calls. We mostly take its presence for granted even when it is accessed by our favorite apps. Our GPS location allows us to navigate, browse the local big chain store inventory, tag our location on photos, get local news, and find our parking spot.
Similarly, the accurate navigation from GPS is also critical for efficient operation of commercial and military vehicles, aircraft, ships, UAVs, missiles, and smart bombs.
GPS Alone Cannot be Trusted!
We generally have pleasant experiences with GPS in our modern phones. With the right software, it gets you from A to B without any issues. However, occasional GPS dropouts do occur, leading to a “loss of GPS” or similar message from our navigation software, for instance, when driving in a tunnel. The fact that dropouts occur should not be surprising when you consider the technology.
GPS satellites orbit at an altitude of about 12,500 miles and each satellite has the radio power equivalent to a conventional light bulb. That results in a minuscule signal strength at the GPS receiver, which makes it very susceptible to radio noise, attenuation, and reflection from tall buildings. It also makes it very easy for attackers to jam with simple, low cost radio transmitters.
Back in 2013, Newark airport was inadvertently hit by a GPS denial attack when an employee, wanting to hide his company vehicle movements from his boss, was driving in the area with a GPS jammer that could be obtained for as little as $100.
The GPS signals are also at risk from legitimate terrestrial transmitters. In the US, the FCC is responsible for keeping the weak signal satellite bands separate from terrestrial ones. But even so, in 2011 a 4G LTE wireless company called LightSquared requested the terrestrial use of spectrum so close to the GPS band that it put the whole network at risk.
Worst still, commercial GPS receivers are susceptible to GPS spoofing attacks. Attackers can connect a strong transmitter to a GPS simulator programmed to fool a target GPS receiver into thinking that it is somewhere it isn’t. An infamous headline of such a spoofing attack was the capture of a US RQ-170 Sentinel UAV by the Iranian government in 2011. This was allegedly done by sending the UAV strong false GPS signals to make it believe it was flying over a friendly airfield instead of hostile territory.