Laser vibrometer identification friend-or-foe (IFF) system

A friend-or-foe (IFF) identification system for identifying the status of a passive target comprising:

• a laser installed on a platform for generating and transmitting a laser beam, said laser including a beam splitter means for dividing the laser beam into a first beam and a second beam;
• a reference including a reference path along which said first beam is directed, said reference including an attenuator interposed therealong for the path length to approximate a distance between the platform and said target, and It mirror positioned at the end of the path for reflecting said first beam back along the path;
• means for directing said second laser beam at said target and for receiving a return beam reflected off said passive target, said target having existing vibrations therewithin prior to and while said second laser beam reflects off the target, said existing vibrations of said target constituting a vibration signature unique to the target, said return beam including said vibration signature of said target, and said return beam being effected by the atmosphere and the surface diffusion effects of the target;
• a processor for processing said return beam and said reference beam to correct the vibration signature of the target for any atmospheric and surface diffusion effects thereby obtain an accurate passive target signature;
• and
• a comparator for comparing the passive target signature against the signature of other objects, the results of the comparison providing the IFF identification.

A method of non-cooperative target IFF identification comprising:

• generating and transmitting a laser beam;
• splitting said laser beam into a first beam and a second beam;
• directing said first beam along a reference path the length of which approximates the distance to said target, and reflecting said first beam back along the path when it reaches the end thereof;
• directing said second laser beam at said non-cooperative target and receiving a return beam reflected off the target, said target having existing vibrations therewithin prior to and while said second laser beam reflects off the target, said existing vibrations of said target constituting a vibration signature unique to the target, said return beam including said vibration signature of the target, and said return beam being effected by the atmosphere and/or the surface diffusion effects of the target;
• processing said return beam and said reference beam together to correct the vibration signature of the target for any atmospheric and/or surface diffusion effects thereby to obtain an accurate target vibration signature;
• and
• comparing said target vibration signature against known vibration signatures of other targets, the results of such comparison providing the IFF identification.