Criminals use GPS jammers to interfere with airport security

　　The use of GPS jammers, long foreseen in navigation circles, has become a reality as criminals employ them to overcome tracking systems and steal vehicles.They are readily available and are certainly being sold and being used. They render our GNSS-based security systems vulnerable to attack.The spectra of the jamming signals radiated by this device are designed to cover the frequency bands in which European 900 MHz, 1800 MHz, and 3G base stations transmit, so preventing mobiles from receiving them and establishing communications.

　　The jammers are relatively simple and crude, but highly effective in preventing the operation of civil GPS receivers.These low-powered transmitters, readily available over the Internet for as little as $150, can block GPS reception in a vehicle’s vicinity.GNSS satellites transmit no more power than a car headlight, yet must illuminate nearly half the Earth’s surface from 20,000 kilometers above it.

　　If not, they can be used to call for assistance; they can also be tracked using cell-site analysis methods.Meanwhile, criminals use multi-spectrum jammers to conduct hijackings, as they can block GPS, mobile and data networks, all at the same time.

　　If a vehicle is to be completely screened from electronic tracking, not only must GPS be disabled in its vicinity, so must mobile phones as well.To prevent that, a jammer can block not only GPS reception but also that of all the mobile phone bands used in the area.Signals reaching a receiver are easily swamped by even a thousandth of a watt of jamming signal radiated near by.