The rise of GPS jammers

All information flows can be intercepted, especially when data is transmitted with wireless technologies. GPSs are no exception to the rule, and face more and more jamming systems. Investigation of a phenomenon whose innovations and fields of application have not stopped surprising us.

In his Texan lab worthy of Géo Trouvetou, Todd Humphreys shows his students the screen of his smartphone: it shows a Google map, with a blue dot showing the geolocation of the university where they are. So far nothing very surprising. Suddenly, the blue dot begins to move on the screen, as if the smartphone was placed in a moving car. Except he’s still here, in the scientist’s hand! The reason for the phenomenon: a small box, present in the workshop, acts as a GPS jammer. “It’s a spoofer (” usurper “), a GPS simulator. It picks up authentic signals from GPS satellites, then re-emits them on the same wavelength after slightly changing the coordinates. The GPS systems of the neighborhood will capture as a priority the false signal of the spoofer, because it is more powerful than that of a satellite located 20 000 kilometers from the Earth. If I installed one on the roof of this building with a good antenna, I could distort all the GPS of the district, and even those of the planes passing over the city “.

Some Consumer GPS jammers are starting to emerge on online stores. They are mainly designed by Chinese companies. But many “do-it-yourselfers” develop their own jammers, which can be dangerous when you know the importance of GPS use in many areas: transport (road, air, sea), logistics, traceability, guidance agricultural machinery, validation of financial exchanges, etc.

The two big families of GPS jammers

No major incident related to a GPS jammer is known to date, but it could easily become a reality. Two types of attack can occur:

Simple jamming: the jammer broadcasts a targeted signal that paralyzes that of the targeted GPS. This one is then disoriented, and stops working.

Advanced jamming: the jammer intercepts the target signal, and modifies it virtually. As in the previous experiment, it is thus possible to display a geolocation or a route different from the actual location or movement.

Known fields of application

GPS jamming will probably be used in multiple situations. Here are the ones we already imagine, or have already been observed:

Disorientation of sensitive public systems (transport, finance, etc.)

Stopping the geolocation of company vehicles (to perform moonlighting or personal trips for example)

Disabling GPS tracking of a protected convoy to initiate an attack, breakage

Bypassing embedded security systems, for example used by some vehicle thieves

Network transmissions can still be intercepted

The use of a GPS to go on vacation is primarily the use of a network: digital data is exchanged between a satellite and a terminal (GPS). As for a PC connected to Wi-Fi box, it is possible to isolate the signal, scrambling, or take control, sometimes even to the detriment of the first user. All the interceptions are imaginable, and the technologies allowing it are more and more numerous.

These interceptions are in fact the good illustration to explain the so-called “Man in the middle” (MITM) attacks, or in good French “Attack of the middle man” (HDM). They make it possible to understand that the stake of these attacks lies in a discreet intrusion between the transmitter and the receiver. Hence the importance of encrypting the transmissions, so that the possible intruder can not act on the transmission, or at least understand it. In Wi-Fi for example, this translates into the adoption of WPA2 encryption.

Jammers jammers, or innovations that self-fuel

While GPS jammers were more the business of specialized individuals (armed forces, spies, terrorists, security companies, etc.), we observe that they are widely democratized henceforth. For example, for example, Garmin sells for 199 € a GPS tracker (tracker) as big as the thumb, and therefore easily concealable in a vehicle, a bag, etc. What satisfy the paranoid of all: jealous husband, worried parent, zealous business leader, etc.