US 8,947,232 B2 · Fault-tolerant distributed fiber optic intrusion detection

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.

Claims23

Dependent claims

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.

3 more elements

Dependencies are inferred from the claim text.

Fault-tolerant distributed fiber optic intrusion detection

Life of this patent

Fault-tolerant distributed fiber optic intrusion detection

Life of this patent

Abstract

Claims23