Optical fiber cable based intrusion detection system
First Claim
1. An apparatus for producing a measurable attenuation to at least one light pulse through a fiber optic cable when said fiber optic cable is subjected to a displacement force, said apparatus comprising:
- a housing having a cable ingress opening and a cable egress opening, said fiber optic cable inserted through said housing through said ingress opening and said egress opening;
securing means disposed within said housing for securing a portion of said fiber optic cable relative to a predetermined position within said housing;
movable securing means disposed within said housing, said movable securing means allowing a second portion of said fiber optic cable to displace relative to said housing when said fiber optic cable is subject to the displacement force; and
light signal attenuation producing means disposed within said housing, said attenuation producing means being responsive to said displacement force, and producing an attenuation to said light pulse wherein said light signal attenuation producing means holds the attenuation even after the displacement force disappears.
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Accused Products
Abstract
There is provided an electronic security system for a perimeter structure that incorporates a fiber optic cable secured to the perimeter structure. Typically the perimeter structure is a fence. A light pulse is transmitted down the fiber optic cable. Mechanical attenuation devices disposed at various locations along the fiber optic cable are responsive to intrusion attempts. The mechanical attenuation devices produce measurable attenuations to the light pulse. Using backscattering light detection technology an intrusion attempt and the location of an intrusion is detected.
71 Citations
37 Claims
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1. An apparatus for producing a measurable attenuation to at least one light pulse through a fiber optic cable when said fiber optic cable is subjected to a displacement force, said apparatus comprising:
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a housing having a cable ingress opening and a cable egress opening, said fiber optic cable inserted through said housing through said ingress opening and said egress opening;
securing means disposed within said housing for securing a portion of said fiber optic cable relative to a predetermined position within said housing;
movable securing means disposed within said housing, said movable securing means allowing a second portion of said fiber optic cable to displace relative to said housing when said fiber optic cable is subject to the displacement force; and
light signal attenuation producing means disposed within said housing, said attenuation producing means being responsive to said displacement force, and producing an attenuation to said light pulse wherein said light signal attenuation producing means holds the attenuation even after the displacement force disappears. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An intrusion detection and location apparatus for an area secured by at least one perimeter fence, said intrusion detection apparatus comprising:
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at least one fiber optic cable secured to said perimeter fence;
light transmission means disposed at a first end of said at least one fiber optic cable for transmitting at least one light pulse from a light source through said at least one fiber optic cable;
light measuring means for measuring the intensity of light at a second end of said at least one fiber optic cable;
intrusion detecting means responsive to said light measuring means;
light backscatter measuring means responsive to said instrusion detection means for measuring the intensity of backscattered light from a second pulse of transmitted light that is the same or different than the at least one light pulse; and
intrusion location means responsive to said light backscatter measuring means. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An intrusion detection and location apparatus for an area secured by at least one perimeter fence, said intrusion detection apparatus comprising:
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at least one fiber optic cable secured to said perimeter fence;
a first light transmission means disposed at a first end of said at least one fiber optic cable for transmitting at least one light pulse through said at least one fiber optic cable;
a first light measuring means for measuring the intensity of light at a second end of said at least one fiber optic cable;
intrusion detecting means responsive to said light measuring means;
a second light transmitting means responsive to said intrusion detecting means for transmitting at least a second pulse of light through said fiber optic cable;
light backscatter measuring means for measuring the intensity of backscattered light from said at least a second pulse of transmitted light; and
intrusion location means responsive to said light backscatter measuring means. - View Dependent Claims (30, 31, 32, 33, 34, 35)
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36. A method for detecting and locating an intrusion into an area having at least a portion bounded by a fence, said fence having at least one fiber optic cable secured thereto, said method comprising:
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transmitting at least one pulse of light through a first end of said at least one fiber optic cable;
producing a known attenuation to a light signal through said at least one fiber optic cable in response to a force applied on said fiber optic cable;
measuring the intensity of said at least one pulse of light at a second end of the at least one fiber optic cable;
determining an intrusion responsive the measured intensity of said at least one pulse of light at the second end of the at least one fiber optic cable;
measuring the intensity of backscattered light at various locations along said at least one fiber optic cable; and
determining an intrusion location responsive to the intensity of backscattered light at various locations along said at least one fiber optic cable.
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37. A method for detecting and locating an intrusion into an area having at least a portion bounded by a fence, said fence having at least one fiber optic cable secured thereto, said method comprising:
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transmitting at least one pulse of light through a first end of said at least one fiber optic cable;
producing a known attenuation to a light signal through said at least one fiber optic cable in response to a force applied on said fiber optic cable;
measuring the intensity of backscattered light from a second end of the at least one fiber optic cable;
determining an intrusion responsive to the detected intensity of backscattered light from said second end of the at least one fiber optic cable;
measuring the intensity of backscattered light at various locations along said at least one fiber optic cable; and
determining an intrusion location responsive to the intensity of backscattered light at various locations along said at least one fiber optic cable.
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Specification