How military grade Russia's GPS satellite signal jammer

　　The trucks are so large that they show up easily in some satellite imagery, according to a recent CSIS threat assessment report. The equipment is "military grade," meaning that Russia spent years developing the system and did not purchase it commercially.

　　That jamming was happening long before the Ukraine invasion began on Feb. 24, as the Russian military "has frequently jammed GPS signals in Ukraine since 2014." That year saw the Russians invade and annex Crimea, which until then had been part of Ukraine.

　　There are multiple global positioning satellite systems in operation now; Russia, China, the U.S. and Europe each has its own, for example. That Russia is only after the ground station signals from one of them: the Navstar system of satellites used by the United States and made available openly to many countries around the world.

　　GPS jammers typically work by using massive radio dishes that throw up radio "noise" that block particular signals, although their efficacy can be hindered by terrain.

　　If you're in a super-mountainous region, your radio frequency isn't going to travel as far, because it can't go through the rock. But if you're somewhere super-flat, jamming would be really effective and go very wide.It’s a totally different kettle of fish when bomb jammers are involved as they are high-power warfare equipment emitting powerful radiations. They normally have a very high output power which could be hazardous to human health if there is constant exposure.