Traffic monitoring
AssigneeQinetiq Limited
InventorsDavid John Hill, Sean Dormer Thomas
Life of this patent
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Abstract
The present invention provides an optical fiber sensor for traffic monitoring, which comprises a former consisting of an elongate plate, and an optical fiber wound onto at least one surface of the elongate plate. The elongate plate is flexible in a direction transverse to the at least one surface such that passage. Traffic over the optical fiber sensor is arranged to cause a variation in at least one predetermined property of an optical signal transmitted through the optical fiber sensor. The resulting sensor has a reduced depth which makes it easier to locate within the surface of a traffic route, has increased flexibility to enable it to confirm to the surface of the traffic route, and has good cross axis sensitivity rejection.
Claims47
An optical fibre sensor for traffic monitoring, comprising:
- a former comprising an elongate plate;
- and
- an optical fibre wound onto at least one surface of the elongate plate, the elongate plate being flexible in a direction transverse to the at least one surface such that passage of traffic over the optical fibre sensor is arranged to cause a variation in at least one predetermined property of an optical signal transmitted through the optical fibre sensor;
- wherein the variation in at least one predetermined property of an optical signal transmitted through the optical fibre comprises a variation in phase, which is detectable by an interferometric interrogation system.
An optical fibre sensor as claimed in any preceding claim, further comprising a coating provided over the elongate plate and optical fibre.
An optical fibre sensor as claimed in any preceding claim, wherein the elongate plate comprises a metal strip.
An optical fibre sensor as claimed in any preceding claim, wherein the optical fibre sensor further comprises a semi-reflective element coupled to at least on end of the optical fibre.
A traffic monitoring system, the system comprising:
- at least one sensor station;
- and
- an interferometric interrogation system;
- wherein the at least one sensor station comprises at least one optical fibre sensor as claimed in any preceding claim, the at least one optical fibre sensor being deployable in a traffic route;
- wherein the interferometric interrogation system is adapted to respond to the variation in said at least one predetermined property produced in the at least one optical fibre sensor due to a force applied by a unit of traffic passing the at least one sensor station.
Dependencies are inferred from the claim text.