Patents by Inventor Andrew Biggerstaff Lewis
Andrew Biggerstaff Lewis has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9945717Abstract: The application describes methods and apparatus for distributed fiber sensing, especially distributed acoustic/strain sensing. The method involves launching interrogating radiation in to an optical fiber and sampling radiation backscattered from within said fiber at a rate so as to acquire a plurality of samples corresponding to each sensing portion of interest. The plurality of samples are divided into separate processing channels and processed to determine a phase value for that channel. A quality metric is then applied to the processed phase data and the data combined to provide an overall phase value for the sensing portion based on the quality metric. The quality metric may be a measure of the degree of similarity of the processed data from the channels. The interrogating radiation may comprise two relatively narrow pulses separated by a relatively wide gap and the sampling rate may be set such that a plurality of substantially independent diversity samples are acquired.Type: GrantFiled: September 6, 2016Date of Patent: April 17, 2018Assignee: Optasense Holdings Ltd.Inventors: Andrew Biggerstaff Lewis, Stuart John Russell
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Patent number: 9909903Abstract: The application describes methods and apparatus for distributed fiber sensing, especially distributed acoustic/strain sensing. The method involves launching at least first and second pulse pairs into an optical fiber, the first and second pulse pairs having the same frequency configuration as one another and being generated such that the phase relationship of the pulses of the first pulse pair has a predetermined relative phase difference to the phase relationship of the pulses of the second pulse pair. In one embodiment there is a frequency difference between the pulses in a pulse pair which is related to the launch rate of the pulse pairs. In another embodiment the phase difference between the pulses in a pair is varied between successive launches. In this way an analytic version of the backscatter interference signal can be generated within the baseband of the sensor.Type: GrantFiled: April 6, 2012Date of Patent: March 6, 2018Assignee: Optasense Holdings Ltd.Inventors: Andrew Biggerstaff Lewis, Stuart John Russell
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Publication number: 20170199075Abstract: The application describes methods and apparatus for distributed fibre sensing, especially distributed acoustic/strain sensing. The method involves launching interrogating radiation in to an optical fibre and sampling radiation backscattered from within said fibre at a rate so as to acquire a plurality of samples corresponding to each sensing portion of interest. The plurality of samples are divided into separate processing channels and processed to determine a phase value for that channel. A quality metric is then applied to the processed phase data and the data combined to provide an overall phase value for the sensing portion based on the quality metric. The quality metric may be a measure of the degree of similarity of the processed data from the channels. The interrogating radiation may comprise two relatively narrow pulses separated by a relatively wide gap and the sampling rate may be set such that a plurality of substantially independent diversity samples are acquired.Type: ApplicationFiled: September 6, 2016Publication date: July 13, 2017Inventors: Andrew Biggerstaff Lewis, Stuart John Russell
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Patent number: 9435668Abstract: The application describes methods and apparatus for distributed fiber sensing, especially distributed acoustic/strain sensing. The method involves launching interrogating radiation in to an optical fiber and sampling radiation backscattered from within said fiber at a rate so as to acquire a plurality of samples corresponding to each sensing portion of interest. The plurality of samples are divided into separate processing channels and processed to determine a phase value for that channel. A quality metric is then applied to the processed phase data and the data combined to provide an overall phase value for the sensing portion based on the quality metric. The quality metric may be a measure of the degree of similarity of the processed data from the channels. The interrogating radiation may comprise two relatively narrow pulses separated by a relatively wide gap and the sampling rate may be set such that a plurality of substantially independent diversity samples are acquired.Type: GrantFiled: April 6, 2012Date of Patent: September 6, 2016Assignee: OPTASENSE HOLDINGS LTD.Inventors: Andrew Biggerstaff Lewis, Stuart John Russell
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Publication number: 20120280117Abstract: The application describes methods and apparatus for distributed fibre sensing, especially distributed acoustic/strain sensing. The method involves launching at least first and second pulse pairs into an optical fibre, the first and second pulse pairs having the same frequency configuration as one another and being generated such that the phase relationship of the pulses of the first pulse pair has a predetermined relative phase difference to the phase relationship of the pulses of the second pulse pair. In one embodiment there is a frequency difference between the pulses in a pulse pair which is related to the launch rate of the pulse pairs. In another embodiment the phase difference between the pulses in a pair is varied between successive launches. In this way an analytic version of the backscatter interference signal can be generated within the baseband of the sensor.Type: ApplicationFiled: April 6, 2012Publication date: November 8, 2012Applicant: QINETIQ LIMITEDInventors: Andrew Biggerstaff Lewis, Stuart John Russell
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Publication number: 20120278043Abstract: The application describes methods and apparatus for distributed fibre sensing, especially distributed acoustic/strain sensing. The method involves launching interrogating radiation in to an optical fibre and sampling radiation backscattered from within said fibre at a rate so as to acquire a plurality of samples corresponding to each sensing portion of interest. The plurality of samples are divided into separate processing channels and processed to determine a phase value for that channel. A quality metric is then applied to the processed phase data and the data combined to provide an overall phase value for the sensing portion based on the quality metric. The quality metric may be a measure of the degree of similarity of the processed data from the channels. The interrogating radiation may comprise two relatively narrow pulses separated by a relatively wide gap and the sampling rate may be set such that a plurality of substantially independent diversity samples are acquired.Type: ApplicationFiled: April 6, 2012Publication date: November 1, 2012Applicant: QINETIQ LIMITEDInventors: Andrew Biggerstaff Lewis, Stuart John Russell
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Publication number: 20040228566Abstract: An apparatus for detecting and/or locating a fibre-optic cable (170) by applying a magnetic field with a component parallel to the cable (170) and detecting the cumulative rotation of polarisation of a polarised beam passing through the magnetic field multiple times. The beam is preferably input into the cable (170) multiple times, with the same polarisation and amplitude each cycle. In this case, a regeneration stage (800) is provided to recycle the beam with the correct amplitude and polarisation. A method of detecting a fibre-optic cable (170) is also disclosed.Type: ApplicationFiled: May 16, 2003Publication date: November 18, 2004Inventors: Andrew Biggerstaff Lewis, Stuart John Russell, John Phillip Dakin
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Patent number: 6650798Abstract: In order to identify a fiber optic cable (10) a beam (14) of polarised light is caused to pass down the cable to a first site (A) at which an electromagnetic field (24) is applied to the cable (10). The electromagnetic field (24) traverses the cable (10) in an essentially transverse direction and has a time-varying component orientated along the length of the cable (10) at the first site (A), with the component varying so that the line integral thereof along the cable (10) is non-zero. This results in a variation in the polarisation of the light, which can then be detected by a polarisation discriminator (20) at a second site (B), thereby to identify the cable (10).Type: GrantFiled: November 6, 2002Date of Patent: November 18, 2003Assignee: Radiodetection LimitedInventors: Stuart John Russell, Andrew Biggerstaff Lewis, John Philip Dakin
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Patent number: 6552548Abstract: A monitoring device defines a boundary for movement of an underground object such as a booring tool. The underground object generates a magnetic field which is detected by the monitoring device. The monitoring device then determines the position of the underground object relative to itself, and hence to the boundary. The movement of the underground object can then be controlled so that it does not cross the boundary. The monitoring device may therefore define a protection zone so that a buried object within that protection zone will not be contacted by the moveable underground object.Type: GrantFiled: June 14, 1999Date of Patent: April 22, 2003Assignee: Radiodetection LimitedInventors: Andrew Biggerstaff Lewis, Richard William Fling
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Publication number: 20030052258Abstract: In order to identify a fiber optic cable (10) a beam (14) of polarised light is caused to pass down the cable to a first site (A) at which an electromagnetic field (24) is applied to the cable (10). The electromagnetic field (24) traverses the cable (10) in an essentially transverse direction and has a time-varying component orientated along the length of the cable (10) at the first site (A), with the component varying so that the line integral thereof along the cable (10) is non-zero. This results in a variation in the polarisation of the light, which can the be detected by a polarisation discriminator (20) at a second site (B), thereby to identify the cable (10).Type: ApplicationFiled: November 6, 2002Publication date: March 20, 2003Applicant: Radiodetection LimitedInventors: Stuart John Russell, Andrew Biggerstaff Lewis, John Philip Dakin
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Patent number: 6480635Abstract: In order to identify a fiber optic cable (10) a beam (14) of polarized light is caused to pass down the cable to a first site (A) at which an electromagnetic field (24) is applied to the cable (10). The electromagnetic field (24) traverses the cable (10) in an essentially transverse direction and has a time-varying component orientated along the length of the cable (10) at the first site (A), with the component varying so that the line integral thereof along the cable (10) is non-zero. This results in a variation in the polarization of the light, which can then be detected by a polarization discriminator (20) at a second site (B), thereby to identify the cable (10).Type: GrantFiled: May 15, 2000Date of Patent: November 12, 2002Assignee: Radio Detection LimitedInventors: Stuart John Russell, Andrew Biggerstaff Lewis, John Philip Dakin
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Patent number: 6297736Abstract: A method of locating a concealed conductor is performed by generating a magnetic field with a direction in which the field is a maximum. The magnetic field is rotated until that direction is directed towards the conductor. In this way, a signal is induced in the conductor which has a maximum value when that direction is directed towards the conductor. The induced signal is detected in the conductor, using a detector arranged to determine the direction of the conductor relative to the detector. The detector detects when the induced signal has the maximum value.Type: GrantFiled: December 30, 1999Date of Patent: October 2, 2001Assignee: Radiodetection LimitedInventors: Andrew Biggerstaff Lewis, Nicholas James Frost
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Patent number: 6236217Abstract: A method of detecting faults on a cable (1) is provided, such a cable (1) having a conductive path, there being a number of sensors (5a, 5b, 5c, 5d, 5e) along the length of the cable (1), each of the sensors shaving a resistance measurement device for detecting the cable to ground resistance of the respective section of the cable (1). The cable to ground resistance at the respective sections are measured and compared with a predetermined value, and if the cable to ground resistance of any one particular section is less than the predetermined value, it is determined that a fault is present in that section.Type: GrantFiled: February 17, 1999Date of Patent: May 22, 2001Inventors: Andrew Biggerstaff Lewis, Andrzej Zbigniew Regini
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Patent number: 6127827Abstract: In order to identify a cable buried underground, a very low frequency voltage signal is applied to the cable and an electric field sensor is brought into proximity with the cable. The sensor thus detects the voltage signal on the cable and so identifies the cable. The sensor is unaffected by one or more additional cables carrying voltage signals, which are proximate the cable of interest, as the electric filters from such additional cables do not pass to the cable of interest. The sensor is mounted on a probe which is mounted into a bore in the soil around the cable of interest. The probes may also carry a magnetometer for detecting magnetic fields generated by low frequency alternating current signals on the cable of interest.Type: GrantFiled: January 16, 1997Date of Patent: October 3, 2000Assignee: Radiodetection LimitedInventor: Andrew Biggerstaff Lewis