Selective wavelength identification friend or foe (swiff)

Abstract

An optical identification friend-or-foe (IFF) system for vehicles comprises a Selective Wavelength IFF (SWIFF) system with a tunable optical beacon being located on each similarly equipped vehicle. That tunable optical beacon includes a light source and wavelength encoder which can select a number of narrow-band optical wavelengths for emission from the beacon, those selected wavelengths forming an identification code for a vehicle. The optical beacon directs the selected wavelengths along an optical path to a diffuser which can irradiate a wide field-of-view around the vehicle with those selected wavelength for detection and identification by other friendly vehicles. The light source may be one that emits a broad range of wavelengths with the encoder providing a number of narrow-band optical filters which can be selectively positioned in the optical path from the light source to the diffuser. Alternatively, the light source and encoder could be a wavelength agile laser source or an array of laser diodes emitting at specific wavelengths and a control unit to select the wavelengths emitted by the laser source or array of diodes. This optical SWIFF system provides a high level of covertness and degree of confidence in the identification of vehicles as being friend-or-foe.