Fault-tolerant distributed fiber optic intrusion detection
First Claim
1. An intrusion detection system for monitoring a premises comprising:
- an optical cable that extends about the premises and has a first end opposite a second end, the optical cable comprising an optical fiber having a first end opposite a second end; and
a highly coherent optical time domain reflectometry means, operably coupled to the first end and the second end of the optical cable, comprising;
a highly coherent optical source to generate a first optical signal to launch into the first end of the optical fiber at a first wavelength and a second optical signal to launch into the second end of the optical fiber at a second wavelength different than the first wavelength; and
signal processing circuitry that analyzes a first backscatter signal and a second backscatter signal received via the first end and the second end, respectively, of the optical fiber in response to the first launched optical signal and the second launched optical signal, respectively, in order to detect an intrusion of the premises, wherein the first and second backscatter signals in the optical fiber are affected by an acoustic wave or pressure incident on the optical cable caused by the intrusion of the premises.
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Accused Products
Abstract
An intrusion detection system for monitoring a premises includes at least one optical cable that houses at least one optical fiber and extends about the premises. Optical time domain reflectometry (OTDR) means is operably coupled to opposite first and second ends of the at least one optical fiber. The OTDR means includes first signal processing circuitry that analyzes the backscatter signal received via the first end of the at least one optical fiber in order to detect an intrusion of the premises, and second signal processing circuitry that analyzes the backscatter signal received via the second end of the at least one optical fiber in order to detect an intrusion of the premises. The redundancy of intrusions decisions made by the first and second signal processing circuitry can be verified. The system preferably further includes means for detecting a break in the at least one fiber, for identifying location of the break, for outputting to a user the location of the break, and for raising an alarm indicating the break.
30 Citations
23 Claims
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1. An intrusion detection system for monitoring a premises comprising:
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an optical cable that extends about the premises and has a first end opposite a second end, the optical cable comprising an optical fiber having a first end opposite a second end; and a highly coherent optical time domain reflectometry means, operably coupled to the first end and the second end of the optical cable, comprising; a highly coherent optical source to generate a first optical signal to launch into the first end of the optical fiber at a first wavelength and a second optical signal to launch into the second end of the optical fiber at a second wavelength different than the first wavelength; and signal processing circuitry that analyzes a first backscatter signal and a second backscatter signal received via the first end and the second end, respectively, of the optical fiber in response to the first launched optical signal and the second launched optical signal, respectively, in order to detect an intrusion of the premises, wherein the first and second backscatter signals in the optical fiber are affected by an acoustic wave or pressure incident on the optical cable caused by the intrusion of the premises. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of detecting intrusion of a premises comprising:
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providing at least one optical cable that extends about the premises, the at least one optical cable having a first end opposite a second end that are coupled to a highly coherent optical time domain reflectometry means, the at least one optical cable comprising an optical fiber having a first end opposite a second end, wherein the highly coherent optical time domain reflectometry means includes a highly coherent optical source to generate first optical signals to launch into the first end of the optical fiber at a first wavelength and second optical signals to launch into the second end of the optical fiber at a second wavelength different than the first wavelength; and using the optical time domain reflectometry means to analyze a first backscatter signal received via the first end of the optical fiber in response to the first optical signals and to analyze a second backscatter signal received via the second end of the optical fiber in response to the second optical signals in order to detect an intrusion of the premises, wherein the first backscatter signal and the second backscatter signal in the optical fiber are affected by an acoustic wave or pressure incident on the optical cable caused by the intrusion of the premises. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification