Quote (Garethsir @ Wed, 25 Feb 2009, 22:15)
ya... for finding the location of random noises?
^ this comment made no sense whatsoever. Doppler effect is the use of a continuous wave frequency(sound being a frequency aslo) to determine the velocity or distance of a moving object. If velocity is already known, distance can be determined, if no distance is known, it can still tell the velocity by measuring the difference in the returned freq and comparing it to the originally transmitted freq. It's basic RADAR principles. The combination of a doppler(determining speed) and a pulse modulated RADAR can provide bearing, range, and velocity of an object. Using a directional antenna with an array of parisitic elements for the received returns, you can determine the target angle, thus having all the factors to determine the altitude of, say, an inbound aircraft. This is all very elementary wave propagation theory. If this is something that you're interested in, and would like more info, please inquire and i could shoot you some pdf's of military training manuals that could further your studies, but this stuff has been in use since before Japan hit Pearl Harbor(well, it was in the testing phase at the time, so was not reliable, but was already developed).