Proximity Fuze - Optical Sensing

Optical Sensing

Optical sensing was developed in 1935, and patented in Great Britain in 1936, by a Swedish inventor, probably Edward W. Brandt, using a petoscope. It was first tested as a part of a detonation device for bombs that were to be dropped on bombers, part of the UK's Air Ministry's "bombs on bombers" concept. It was considered (and later patented by Brandt) for use with anti-aircraft missiles. It used then a toroidal lens, that concentrated all light out of a plane perpendicular to the missile's main axis onto a photo cell. When the cell current changed a certain amount in a certain time interval, the detonation was triggered.

Some modern air-to-air missiles use lasers. They project narrow beams of laser light perpendicular to the flight of the missile. As the missile cruises towards the target the laser energy simply beams out into space. As the missile passes its target some of the energy strikes the target and is reflected back to the missile where detectors sense it and detonate the warhead.