Triggers
Radar proximity fuzes are attached to anti-aircraft artillery shells or other explosive devices, and detonate the device when it approaches a large object. They use a small rapidly pulsing omnidirectional radar, usually with a powerful battery that has a long storage life, and a very short operational life. The fuzes used in anti-aircraft artillery have to be mechanically designed to accept fifty thousandg, yet still be cheap enough to throw away.
Read more about this topic: Radar Configurations And Types