Method and apparatus for disturbance detection
First Claim
1. A system for monitoring a detection area, comprising:
- a coherent light source transmitting a first plurality of interrogating pulses, whereinthe first plurality of interrogating pulses includes a first subset of interrogating pulses and a second subset of interrogating pulses, the first subset of interrogating pulses comprising a substantially different pulse profile in relation to the second subset of interrogating pulses, the first subset of interrogating pulses being arranged in a deterministic fashion in relation to the second subset of interrogating pulses;
a first optical fiber of a first predetermined length disposed in the detection area;
a first coupler disposed between the coherent light source and the first optical fiber and coupled to the first optical fiber at a first terminal, wherein the first coupler is configured to;
provide the first plurality of interrogating pulses to the first optical fiber through the first terminal,receive at least a first plurality of backscattered pulses generated in the first optical fiber as reflections of at least a portion the first plurality of interrogating pulses, andprovide the first plurality of backscattered pulses through a second terminal;
a second optical fiber of a second predetermined length coupled to the second terminal of the first coupler, the second optical fiber receiving the first plurality of backscattered light pulses from the first coupler; and
a first detector coupled to the second optical fiber, the first detector configured to;
receive the first plurality of backscattered pulses, andanalyze the first plurality of backscattered pulses to determine a type of disturbance based on a correlation among the first plurality of backscattered pulses, and to identify a first location of a first fast physical disturbance in the detection area.
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Accused Products
Abstract
A sweep sensor may include a signal source, a propagation medium, and a detector. By transmitting an interrogating signal from the signal source into the propagation medium, detectable disturbances along the medium can physically alter the characteristics of the medium, which may cause a measurable change in the backscattered signal at the detector. Based on the change, it may be possible to locate the geographic origins of the physical disturbances along the propagation medium, or to determine the nature of the disturbances, or both. For example, it is generally possible to estimate the approximate distance between the detector and the disturbance given the time required to obtain the backscattered signal and the velocity of the signal source in the propagation medium. Further, in some embodiments, it is possible to quantify the amount of disturbance.
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Citations
20 Claims
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1. A system for monitoring a detection area, comprising:
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a coherent light source transmitting a first plurality of interrogating pulses, wherein the first plurality of interrogating pulses includes a first subset of interrogating pulses and a second subset of interrogating pulses, the first subset of interrogating pulses comprising a substantially different pulse profile in relation to the second subset of interrogating pulses, the first subset of interrogating pulses being arranged in a deterministic fashion in relation to the second subset of interrogating pulses; a first optical fiber of a first predetermined length disposed in the detection area; a first coupler disposed between the coherent light source and the first optical fiber and coupled to the first optical fiber at a first terminal, wherein the first coupler is configured to; provide the first plurality of interrogating pulses to the first optical fiber through the first terminal, receive at least a first plurality of backscattered pulses generated in the first optical fiber as reflections of at least a portion the first plurality of interrogating pulses, and provide the first plurality of backscattered pulses through a second terminal; a second optical fiber of a second predetermined length coupled to the second terminal of the first coupler, the second optical fiber receiving the first plurality of backscattered light pulses from the first coupler; and a first detector coupled to the second optical fiber, the first detector configured to; receive the first plurality of backscattered pulses, and analyze the first plurality of backscattered pulses to determine a type of disturbance based on a correlation among the first plurality of backscattered pulses, and to identify a first location of a first fast physical disturbance in the detection area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for detecting a disturbance comprising:
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transmitting a first plurality of interrogating pulses from a light source, the first plurality of interrogating pulses including a first subset of interrogating pulses and a second subset of interrogating pulses, the first subset of interrogating pulses comprising a substantially different pulse profile in relation to the second subset of interrogating pulses, the first subset of interrogating pulses being arranged in a deterministic fashion in relation to the second subset of interrogating pulses; transmitting at least a second plurality of interrogating pulses from the light source, the second plurality of interrogating pulses including a third subset of interrogating pulses and a fourth subset of interrogating pulses, the third subset of interrogating pulses comprising a substantially different pulse profile in relation to the fourth subset of interrogating pulses, the third subset of interrogating pulses being arranged in a deterministic fashion in relation to the fourth subset of interrogating pulses; transmitting the first plurality of interrogating pulses and the second plurality of interrogating pulses into a first optical fiber disposed in a detection area, wherein at least a portion of the first plurality of interrogating pulses generate a first plurality of backscattered pulses and at least a portion of the second plurality of interrogating pulses generate a second plurality of backscattered pulses; receiving the first plurality of backscattered pulses and the second plurality of backscattered pulses at a detector; collecting the first plurality of backscattered pulses and the second plurality of backscattered pulses in a storage medium; and analyzing the first plurality of backscattered pulses and the second plurality of backscattered pulses, the analyzing comprising the steps of; identifying a pulse profile associated with each of the first plurality of backscattered pulses and the second plurality of backscattered pulses, and identifying intensity values in each of the first plurality of backscattered pulses and the second plurality of backscattered pulses corresponding to a first plurality of locations in the detection area, for each of the first plurality of locations, performing the steps of; constructing a first trace of the intensity values from the first plurality of backscattered pulses, where each intensity is associated with the pulse profile of a corresponding interrogating pulse of the first plurality of interrogating pulses, constructing a second trace of the intensity values from the second plurality of backscattered pulses, where each intensity is associated with the pulse profile of a corresponding interrogating pulse of the second plurality of interrogating pulses, comparing the first trace to at least the second trace, quantifying a correlation between the first trace and the second trace, and identifying a first location of a first fast physical disturbance in the detection area causing a difference between the first trace and the second trace. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for detecting a physical disturbance comprising:
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a coherent light source transmitting a light wave with periodically changing parameters, the light source generating a first sweep cycle including a first plurality of interrogating pulses and at least a second sweep cycle including a second plurality of interrogating pulses; a first optical fiber of a predetermined length disposed in a detection area, wherein the first optical fiber receives the first sweep cycle and the second sweep cycle and reflects at least a portion of the first sweep cycle as a first backscattered sweep cycle including a first plurality of backscattered pulses and at least a portion of the second sweep cycle as a second backscattered sweep cycle including a second plurality of backscattered pulses; and a detector configured to; receive the first backscattered sweep cycle and the second backscattered sweep cycle from the first optical fiber; beginning with the first backscattered sweep cycle and the second backscattered sweep cycle, perform iterative steps of; identifying a pulse profile associated with each of the first plurality of backscattered pulses and the second plurality of backscattered pulses, identifying intensity values in each of the first plurality of backscattered pulses and the second plurality of backscattered pulses corresponding to a first plurality of locations in the detection area, constructing a first trace of the intensity values from the first plurality of backscattered pulses, where each intensity is associated with the pulse profile of a corresponding interrogating pulse of the first plurality of interrogating pulses, constructing a second trace of the intensity values from the second plurality of backscattered pulses, where each intensity is associated with the pulse profile of a corresponding interrogating pulse of the second plurality of interrogating pulses, comparing the first trace of the first backscattered sweep cycle to at least the second trace of the second backscattered sweep cycle, quantifying a correlation between the first backscattered sweep cycle and the second backscattered sweep cycle, and identifying a first location of a first fast physical disturbance in the detection area causing a difference between the first trace and the second trace. - View Dependent Claims (19, 20)
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Specification