Coded heat thwarts friendly fire

日期:2017-11-19 03:33:41 作者:堵刹 阅读:

By Jonathan Beard AIRCRAFT, tanks and soldiers may soon carry small infrared transmitters that will protect them from “friendly fire” without giving away their presence to the enemy. Being shot at by your own side is an ever-present danger on the battlefield. Systems to prevent this, known as identification, friend or foe (IFF), already exist, but they rely on signals that can easily be picked up by your opponents. Now a scientist at Los Alamos National Laboratory in New Mexico has patented a technique called synchronous detection for IFF, which hides a coded infrared signal in the background infrared haze of a battlefield. “The essence of synchronous or lock-in detection is the fact that battlefields are hot places, and everything on them is emitting infrared radiation,” says Roger Stutz of Los Alamos. “Our device is a small infrared transmitter whose signal is so weak that it is completely masked by background signals.” This weak signal would be broadcast at a secret frequency, or modulated in time-coded pulses. “The other half of the IFF system will be a receiver with a phase-locked amplifier,” says Stutz. “Like a radio tuned to just one station, it will only pick up the secret signal and ignore the rest of the spectrum.” When the receiver detects the coded transmission, it amplifies and decodes it, and displays the identity of its source on a computer screen. The IFF codes or frequencies could be changed as often as every hour, Stutz says. This would make them practically undetectable, as he estimates that even a well-equipped enemy would take days to pick out a single transmitter from the background of infrared noise. Although Los Alamos developed the idea for military use,