Interference hampers the ability of GPS devices to determine the correct location

　　A GPS jamming unit is generally small and self-contained, so the user can readily transport and hide it. The device typically sends out a signal of 1575.42 or 1227.60 MHz. This signal then gets broadcast over a radius of five to 10 meters.

　　Up until recently, these GPS jammers would draw power from the cigarette lighter in a vehicle, although today's users typically plug them into a vehicle's USB port. The jammer needs to be very close to the GPS tracker to work, which is why most people use them to thwart tracking devices installed in vehicles by employers. Jammers are prompt to start up and are usually ready to operate in just a few seconds. They also use relatively little power. That makes them easy to turn on when needed and switch off quickly to avoid detection.

　　The danger of such devices is obvious,However, because someone using a jammer can unplug it in a matter of seconds, it is difficult to catch them in the act.

　　Although jamming is more of a civilian activity, it has occurred in the military sphere as well. In 2015, the Department of Homeland Security confirmed that drug cartels were spoofing and jamming the drones used for U.S.-Mexico border surveillance.