Spatial averaging method for coherent distributed acoustic sensing
AssigneeNEC Laboratories America, Inc.
InventorsJunqiang HU, Yue-Kai HUANG, Ezra IP
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Abstract
Aspects of the present disclosure describe systems, methods and structures for coherent distributed sensing that employs a moving average method among locations along a sensing fiber employing a user configured number of taps that involves location grouping and a group's internal phase alignment followed by an inter-group phase alignment and combining. Our method employs two steps of rotation to achieve the alignment: intra-group rotation and inter-group rotation to align the phase of all participating sensing fiber locations.
Claims10
A spatial averaging method for a coherent distributed acoustic sensing (DAS) system comprising:
- generating by an interrogator, interrogating light and sending it into a length of optical sensing fiber;
- detecting by a coherent detector, backscattered light that results from the interrogating light sent into the optical sensing fiber;
- generating and outputting by a coherent detector, signals indicative of detected backscattered light;
- and
- analyzing by a signal processor, the outputted signals indicative of detected backscattered light and determining strain signals associated with location(s) along the length of the optical sensing fiber that are indicative of a vibration and acoustic environment of the optical sensing fiber at the location(s);
- SAID METHOD CHARACTERIZED IN THAT:
- complex products (beating products) of outputted signals for two locations along the length of the optical sensing fiber are used to determine a phase change in-between every location along the length of the optical sensing fiber.
Dependencies are inferred from the claim text.