×

Optical fiber intrusion location sensor for perimeter protection of precincts

  • US 4,931,771 A
  • Filed: 09/27/1988
  • Issued: 06/05/1990
  • Est. Priority Date: 09/27/1988
  • Status: Expired due to Fees
First Claim
Patent Images

1. A perimeter protection system for use in indicating the location of an intrusion into a protected area, said system comprising:

  • a light source for generating a light beam;

    display means having a plurality of display areas;

    a plurality of multimode gradient index optic fiber loops, each varying in length from each other by predetermined amounts and having every portion highly sensitive and substantially uniformly sensitive to an external disturbance applied at any point, said each having an input end coupled to said source of light for receiving said light beam, and said each loop having an output end coupled to said display means for projecting said light beam propagated along the length of said each of said plurality of optic fiber loops onto a different one of said plurality of display areas,said plurality of multimode gradient index optic fiber loops forming a cable and having said input and said output ends at one end of said cable, said cable being positionable around a periphery of said protected area, said plurality of multimode gradient index optic fiber loops being positioned in said cable so that the distance along the cable of successive loops is equal to said predetermined amounts,said each of said plurality of multimode gradient index optic fiber loops when in an undisturbed state conducting said light beam which projects a first type of pattern from said second end and when disturbed projects a dynamically varying beam which produces a transient characteristic second type of pattern from said second end;

    said display means sensing said first type of pattern projecting onto each of said plurality of display areas, indications representing that there was no intrusion into said protected area, and sensing said second type of pattern projecting onto one or more of said plurality of display areas, indications representing the location of the intrusion.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×