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Because of the threat of rocket attacks, GPS signals in Israel are being deliberately jammed. This has a variety of effects.
It’s all about this: In Israel, conventional navigation systems on cell phones or car sat navs hardly work anymore. Reason: The Israeli army is jamming the GPS signals in the country – as protection against possible rocket and drone attacks. In many cases, the missiles also obtain their navigation data, i.e. flight and target data, from the GPS satellites in Earth orbit. There are basically two types of intentional interference with navigation satellite signals: jamming and spoofing.
This is how the malfunction works: The GPS satellites – or those of the European navigation system Galileo – orbit the earth at an altitude of around 20,000 kilometers. The GPS signal on Earth is correspondingly weak – and it can be easily disrupted. When jamming, the signal is disrupted to such an extent using jammers that navigation devices, such as cell phones, no longer work at all. With spoofing, on the other hand, a false signal is sent out, which overrides the original signal and causes the navigation device to display an incorrect position.
The consequences: The non-existent or unreliable GPS signals have an impact in many areas. For example, airline pilots have to resort to other means of navigation, delivery services can no longer rely on their navigation system and may have to consult paper maps. But there are also problems for industries that rely on extremely precise time information. Because that’s exactly what the navigation infrastructure also delivers: the most precise time information thanks to atomic clocks.
Affected industries: Mobile communications, for example, rely on the precise time signals from the GPS satellites, as they synchronize the devices in the network using the precise GPS clock. The situation is similar with the power grids – this is about the precise recording of voltage fluctuations – or data centers, for example in banks, which also rely on the most precise time information. The GPS signal is often used as a high-precision clock. In this way, the expenditure on the expensive atomic clocks that would otherwise be necessary can be saved.
Situation in Switzerland: Upon request, Swisscom assures that it uses various sources for synchronization, so a GPS malfunction would have no impact. Commercial aviation, for its part, is fundamentally prepared for satellite failures, writes the Federal Office of Civil Aviation upon request. The situation is different for light aircraft up to 5.7 tons. Skyguide would have to take measures here. The postal service, in turn, emphasizes that it does not rely on GPS for parcel delivery. And there is no information about this from the electricity network operator Swissgrid – for security reasons.
Measures against disruption: Spoofing and jamming can be combated with targeted measures. For example, there are special receiving antennas that only take into account signals from above, i.e. from satellites, but not signals from the side, i.e. from jammers, for example. The satellites also “sign” their signals so that receivers can identify them as the correct ones. However, there is no such thing as 100 percent security: it’s a cat and mouse game between attacker and defender, who are always coming up with new methods.