Fibre optic distributed sensing
First Claim
1. A method of distributed sensing comprising the steps of:
- interrogating an optical fiber with electromagnetic radiation;
detecting electromagnetic radiation which is back-scattered from the optical fiber;
processing said detected back-scattered radiation to provide a measurement signal for each of a plurality of longitudinal sensing portions of the optical fiber; and
analysing the measurement signals from the longitudinal sensing portions to detect events of interest, wherein the method comprisesanalysing the measurement signals of a first subset of longitudinal sensing portions to provide a first zone having a first sensing function and analysing the measurement signals of at least a second subset of longitudinal sensing portions to provide at least a second zone having a second, different, sensing function, wherein the measurement signals from the first zone are analysed to determine if the measurement signals match a first characteristic or signature of a first event of interest and the measurement signals from the second zone are analyzed to determine if the measurement signals match a second characteristic or signature of a second, different, event of interest.
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Abstract
A method of distributed fiber optic sensing is described in which an optical fiber (104) is interrogated with electromagnetic radiation; back-scattered radiation is detected; and the returns are processed to provide a measurement signal (310) for each of a plurality of longitudinal sensing portions of the optical fiber. The method comprises analyzing the measurement signals of a first subset of longitudinal sensing portions to provide a first zone (306a) having a first sensing function and analyzing the measurement signals of at least a second subset of longitudinal sensing portions to provide at least a second zone (306b) having a second, different, sensing function. The different sensing functions may include detecting different events of interest. In some embodiments the geometry of the fiber may provide different sensing zones (406a, 406b).
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Citations
36 Claims
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1. A method of distributed sensing comprising the steps of:
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interrogating an optical fiber with electromagnetic radiation; detecting electromagnetic radiation which is back-scattered from the optical fiber; processing said detected back-scattered radiation to provide a measurement signal for each of a plurality of longitudinal sensing portions of the optical fiber; and analysing the measurement signals from the longitudinal sensing portions to detect events of interest, wherein the method comprises analysing the measurement signals of a first subset of longitudinal sensing portions to provide a first zone having a first sensing function and analysing the measurement signals of at least a second subset of longitudinal sensing portions to provide at least a second zone having a second, different, sensing function, wherein the measurement signals from the first zone are analysed to determine if the measurement signals match a first characteristic or signature of a first event of interest and the measurement signals from the second zone are analyzed to determine if the measurement signals match a second characteristic or signature of a second, different, event of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 35)
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21. A method of processing data from a distributed fiber optic sensor comprising the steps of:
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taking data corresponding to detected electromagnetic radiation which has been back-scattered from an optical fiber; processing said data to provide a measurement signal for each of a plurality of longitudinal sensing portions of the optical fiber; and analysing the measurement signals from the longitudinal sensing portions to detect events of interest, wherein the method comprises analysing the measurement signals of a first subset of longitudinal sensing portions to provide a first zone having a first sensing function and analysing the measurement signals of at least a second subset of longitudinal sensing portions to provide at least a second zone having a second, different, sensing function, wherein the measurement signals from the first zone are analysed to determine if the measurement signals match a first characteristic or signature of a first event of interest and the measurement signals from the second zone are analyzed to determine if the measurement signals match a second characteristic or signature of a second, different, event of interest.
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22. A distributed fiber optic sensor apparatus comprising:
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an optical fiber; a source of electromagnetic radiation configured to launch electromagnetic radiation into said fiber; a detector for detecting electromagnetic radiation back-scattered from said fiber; and a processor configured to; analyse the back-scattered radiation to determine a measurement signal for a plurality of discrete longitudinal sensing portions of the optic fiber;
wherein the distributed fiber optic sensor comprises a first zone having a first sensing function, the first zone corresponding to a first subset of said longitudinal sensing portions and at least a second zone having a second, different, sensing function, the second zone corresponding to a second, different, subset of said longitudinal sensing portions, wherein the measurement signals from the first zone are analysed to determine if the measurement signals match a first characteristic or signature of a first event of interest and the measurement signals from the second zone are analyzed to determine if the measurement signals match a second characteristic or signature of a second, different, event of interest. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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36. A method of distributed sensing comprising the steps of:
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interrogating an optical fiber with electromagnetic radiation; detecting electromagnetic radiation which is Rayleigh back-scattered from the optical fiber; processing said detected back-scattered radiation to provide a measurement signal for each of a plurality of longitudinal sensing portions of the optical fiber; and analysing the measurement signals from the longitudinal sensing portions to detect events of interest, wherein the method comprises analysing the measurement signals of a first subset of longitudinal sensing portions to provide a first zone having a first sensing function and analysing the measurement signals of at least a second subset of longitudinal sensing portions to provide at least a second zone having a second, different, sensing function, wherein the measurement signals from the first zone are analysed to determine if the measurement signals match a first characteristic or signature of a first event of interest and the measurement signals from the second zone are analyzed to determine if the measurement signals match a second characteristic or signature of a second, different, event of interest.
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Specification