Radar jamming and deception

A GPS Jammer (Eng. " GPS jammer ") is a jammer for the signals from the Global Positioning System (GPS), a satellite-based global positioning system, which is operated by the Department of Defense.

Due to the relatively low transmission power of the satellites and the orbit of 20,200 kilometers above the earth's surface the GPS signals can only be received with a very low field strength. Therefore, avoid the reception of the GPS satellites already interfering signals with low field strength. An additional modulation (eg noise modulation ) of a jammer can partly or even completely prevent the GPS reception. Through this small perturbation necessary, a GPS jammer for the near field (about 10 m ) can be very small.

A practical structure of a simple GPS Jammers can be found in the online magazine Phrack. But even government agencies such as the Ministry of Defence in the UK test GPS Jammer. The GPS can also be disturbed unintentionally: for example, the 15th harmonic ( 14th harmonic ) of the local oscillator falls exactly on the civilian GPS frequency L1 ( 1575.42 MHz), when set to an FM radio frequency of 94.3 MHz is. This can be in the immediate vicinity of the radio lead to the receive errors of the GPS receiver.

Unlike a GPS Jammer that significantly more sophisticated GPS spoofing interfere with the satellite signal not only, but sends manipulated GPS data.

Navigation warfare

The navigation system GPS is a military system. The term navigation warfare ( Navwar, dt sinngem. " Warfare over navigation " ), sums put together strategies to use GPS on an enemy and exclude him from a use of the system. A scenario based to throwing a large number of small Jammer about a crisis area and to interfere with the reception on the floor of the C / A signal.

The end of 2011 to have been " hijacked" by Iran via the manipulation of the GPS a U.S. reconnaissance drone.

Defense against GPS Jammers

The signal strength of GPS is extremely weak with about -155 dBW. A jammer from a few watts suppressed in the lobby virtually any navigation signal. To minimize the effect of GPS Jammers, GPS antennas can be used with pronounced directivity in certain applications (such as in aviation technology ). These antennas receive signals only from the desired direction - and that's not the noise of GPS Jammers, which are on the ground. Another way to reduce the effect of GPS Jammers, is the combination with other navigation systems, such as an inertial navigation system ( INS).