Evaluating the position of a disturbance
First Claim
1. A position sensor including:
- an optical waveguide;
a transmission stage for launching a sensing signal into the waveguide;
a receiving stage arranged to receive a returned sensing signal, which returned sensing signal is a time distributed signal derived from backscattered components of the sensing signal, the waveguide being arranged along a path having a plurality of overlap regions such that a disturbance in an overlap region causes a first disturbance feature and a second disturbance feature in the returned sensing signal; and
monitoring means for monitoring the returned signal, such that a respective time of return can be associated with the first disturbance feature and with the second disturbance feature;
wherein the sensing signal comprise a series of pairs of pulses, each pair of pulses having been generated by power-splitting a single pulse, wherein each member of a respective pair of pulses is temporally off-set from the other member of said respective pair of pulses.
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Accused Products
Abstract
The present invention relates to a method of and apparatus for evaluating the position of a disturbance, in particular using a waveguide having a plurality of overlap regions. A position sensor is provided including: an optical waveguide; a transmission stage for launching a sensing signal into the waveguide; a receiving stage arranged to receive a returned sensing signals which returned sensing signal is a time distributed signal derived from backscattered components of the sensing signal, the waveguide being arranged along a path having a plurality of overlap regions such that a disturbance in an overlap region causes a first disturbance feature and a second disturbance feature in the returned sensing signal; and, monitoring means for monitoring the returned signal, such that a respective time of return can be associated with the first and second disturbance feature. Both return features can then be used to evaluate the position of the disturbance so as to enhance the resolution of the position sensor.
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Citations
27 Claims
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1. A position sensor including:
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an optical waveguide; a transmission stage for launching a sensing signal into the waveguide; a receiving stage arranged to receive a returned sensing signal, which returned sensing signal is a time distributed signal derived from backscattered components of the sensing signal, the waveguide being arranged along a path having a plurality of overlap regions such that a disturbance in an overlap region causes a first disturbance feature and a second disturbance feature in the returned sensing signal; and monitoring means for monitoring the returned signal, such that a respective time of return can be associated with the first disturbance feature and with the second disturbance feature; wherein the sensing signal comprise a series of pairs of pulses, each pair of pulses having been generated by power-splitting a single pulse, wherein each member of a respective pair of pulses is temporally off-set from the other member of said respective pair of pulses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of sensing position, including the steps of:
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(i) transmitting a sensing signal along a waveguide; (ii) monitoring a returned sensing signal, the returned sensing signal being derived from components of the sensing signal that are returned by a process of distributed backscattering as the sensing signal propagates along the waveguide, wherein the waveguide is arranged along a path having a plurality of overlap regions such that a disturbance in an overlap region causes a first disturbance feature and a second disturbance feature in the returned sensing signal, which first and second disturbance features correspond to respective spaced apart positions along the fibre path; and (iii) using a temporal characteristic in the first and second disturbance features to determine which of the overlap regions the disturbance originates from; wherein said sensing signal comprises a series of pairs of pulses, each pair of pulses having been generated by power-splitting a single pulse, wherein each member of a respective pair of pulses is temporally off-set from the other member of said respective pair of pulses. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A position sensor including:
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an optical waveguide; a transmission stage for launching a sensing signal into the waveguide; a receiving stage arranged to receive a returned sensing signal, which returned sensing signal is a time distributed signal derived from backscattered components of the sensing signal, the waveguide being arranged along a path having a plurality of overlap regions such that a disturbance in an overlap region causes a first disturbance feature and a second disturbance feature in the returned sensing signal; and monitoring means for monitoring the returned signal, such that a respective time of return can be associated with the first disturbance feature and with the second disturbance feature; wherein the sensing signals are pulses, each having a path resolution length associated therewith; and wherein the geographical separation between at least some of the self-crossing points is less than the path resolution length. - View Dependent Claims (24)
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25. A position sensor including:
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an optical waveguide; a transmission stage for launching a sensing signal into the waveguide; a receiving stage arranged to receive a returned sensing signal, which returned sensing signal is a time distributed signal derived from backscattered components of the sensing signal, the waveguide being arranged along a path having a plurality of overlap regions such that a disturbance in an overlap region causes a first disturbance feature and a second disturbance feature in the returned sensing signal; and monitoring means for monitoring the returned signal, such that a respective time of return can be associated with the first disturbance feature and with the second disturbance feature; wherein the sensing signals are pulses, each having a path resolution length associated therewith; and wherein an extension stage is provided between adjacent first sensing portions and/or between adjacent second sensing portions and wherein the path length of each extension stage is at least substantially greater than the path resolution length. - View Dependent Claims (26, 27)
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Specification