A proximity fuse (sometimes spelled "fuze") is a fuse that is designed to detonate an explosive automatically when close enough to the target to destroy it. By sending out radio waves that are reflected by the target and comparing the frequency of the outgoing waves to the incoming waves, a radio proximity fuse uses the Doppler effect to determine its proximity to a target. When the incoming waves sharply increase in frequency, the target is at its closest possible position. In an explosive device, a fuse is the part of the device that causes it to function. ... This article is concerned solely with chemical explosives. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... The term reflection (also spelt reflexion) can refer to several different concepts: In mathematics, reflection is the transformation of a space. ... A source of waves moving to the left. ... For distance between people, see proxemics. ...

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). A missile (British English: miss-isle; U.S. English: missl) is, in general, a projectile—that is, something thrown or otherwise propelled. ...

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). A shell is a projectile, which, as opposed to a bullet, is not only shot by explosives, but also contains explosives itself. ...

Use of timing to produce air bursts against ground targets requires observers to provide information for adjusting the timing. This is not practical in all situations and is slow in any event. Proximity fuses remove these problems.

The proximity fuse was developed through a U.S. and British collaboration during World War II. Vannevar Bush, head of the U.S. Office of Scientific Research and Development (OSRD) during this war, credits it with three significant effects. It was important in defense from Japanese Kamikaze attacks in the Pacific. It was an important part of the radar-controlled anti-aircraft batteries that finally neutralized the German V1 bomb attacks on England. Third, it was released for use in land warfare just in time for use in the Battle of the Bulge, where it decimated German divisions caught in the open. The Germans felt safe from timed fire because the weather prevented accurate observation. Bush cites an estimated 7 times increase in the effect of artillery with this innovation. The United States of America — also referred to as the United States, the U.S.A., the U.S., America, the States, or (archaically) Columbia—is a federal republic of 50 states located primarily in central North America (with the exception of two states: Alaska and Hawaii). ... The word British has several different uses. ... Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km into the air. ... Vannevar Bush (March 11, 1890–June 30, 1974) was an American engineer, inventor, and politician. ... The term Japanese can have several meanings: Japanese people - people of Japanese ancestry living in Japan Japanese language Japan Mainland Japan Ethnic Japanese - people of Japanese ancestry living outside Japan Japanese-American - an article primarily about the immigration and integration Japanese-Brazilian - Japanese-Brazilians in the city of São Paulo... A kamikaze, a Mitsubishi Zero in this case, about to hit the USS Missouri. ... The Pacific Ocean (from the Latin name Mare Pacificum, peaceful sea, bestowed upon it by the Portuguese explorer Ferdinand Magellan) is the worlds largest body of water. ... The word German can mean: From or related to Germany or its predecessor states - see also the German language Germanic tribes Holy Roman Empire (843-1806) German Confederation (1815-1866) North German Confederation (1867 - 1871) Germany, the modern nation-state founded in 1871 When used to denote a person, Germans... The term V1 can refer to: The V-1 flying bomb, the first modern cruise missile, developed by the German Luftwaffe during the Second World War Decision speed, where an aircraft pilot must opt to abort the take-off or continue the run for lift-off at V2 speed. ... Royal motto: Dieu et mon droit (French: God and my right) Englands location within the UK Official language English de facto Capital London de facto Largest city London Area  - Total Ranked 1st UK 130,395 km² Population  - Total (2001)  - Density Ranked 1st UK 49,138,831 377/km² Religion... The German Ardennes Offensive1, popularly known as the Battle of the Bulge, started in late December 1944 and was the last major German offensive on the Western Front during World War II. The German army had intended to split the Allied line in half, capturing Antwerp and then proceeding to...

Proximity fuses were also used on the first atomic bombs. The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ...

References

• Pieces of the Action by Vannevar Bush, William Morrow and Co., inc. 1970
• An account of the development and initial introduction of proximity fuses is given in The Deadly Fuze by Ralph B Baldwin (UK Edition published by Janes, 1980. ISBN 0 354 01234 6). Dr Baldwin was a member of the Johns Hopkins University team headed by Merle A Tuve that did most of the work.

The Johns Hopkins University is an internationally prestigious private institution of higher learning located in Baltimore, Maryland. ...

External link

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