9 September 1998

Lovegety Goes to Battle

Existing systems to distinguish friendly aircraft -- or tanks or soldiers or anything else on a battlefield -- from those of an enemy rely on active transmissions which can give away a location to anyone with the proper listening equipment. Los Alamos researchers have developed an identification system that allows "friends" to recognize each other while giving nothing away to others. The system, called synchronous identification of friendly targets, uses a method of frequency locking to identify a weak signal that is buried in the normal radiant energy emitted by an airplane, tank or person. The device, for which a patent was recently awarded, is portable and reliable, and it can be easily modified to prevent an enemy from determining its operating characteristics.