Proximity fuse

Before their invention, detonation had to be induced either by direct contact, time since launch, or height.

All of these have significant disadvantages. Getting direct contact with a relatively small moving target is hard (even ignoring the effect of wind); to set a time- or height-triggered fuse one must measure the height of the target (or even predict the height of the target at the time one will be able to get a missile in its neighbourhood).

With a proximity fuse, all one has to worry about is getting a shell or missile on a trajectory that, at some time, will pass close by the target (that still is a significant problem).

External link

• http://www.history.navy.mil/faqs/faq96-1.htm gives much more information on proximity fuses