US-12618708-B2 - Efficient method of automated buried cable determination for cable status monitoring

Abstract

A distributed fiber optic sensing (DFOS) system and method employing a fiber optic sensor cable that autonomously collects DFOS data and employs artificial intelligence/machine learning (AI/ML) to distinguish sections of the fiber optic sensor cable that are above ground (aerial), below ground (buried), and buried but occasionally above ground, in addition to any change(s) that occur with respect to the fiber optic sensor cable at such sections.

Inventors

• Shaobo HAN
• Ming-Fang Huang
• Ting Wang

Assignees

• NEC LABORATORIES AMERICA, INC.

Dates

Publication Date

20260505

Application Date

20230511

Claims (5)

1. 1 . An automated method for determining buried optical fiber cable locations comprising: providing a distributed fiber optic sensing (DFOS) system including a length of optical sensor fiber; an optical interrogator in optical communication with the length of optical sensor fiber, the optical interrogator configured to generate optical pulses from laser light, introduce the pulses into the optical sensor fiber and receive backscattered signals from the optical sensor fiber, and an analyzer that analyzes the received backscattered signals, the received backscattered signals originating at a plurality of locations along the length of the optical sensor fiber; continuously operating the DFOS system and collecting received backscattered signals from the plurality of locations along the length of the optical sensing fiber, and analyzing the received backscattered signals by applying a high-pass filter with cut point frequency to the received backscattered signals to generate a vector of intensity values, wherein each intensity value corresponds to one of the plurality of locations; for each individual one of the plurality of locations, determining quantile statistics as summary statistics based on the intensity values over a period of time; applying a median filter on the determined summary statistics to generate a filtered vector, performing spatial clustering on the filtered vector to partition the plurality of locations into one or more clusters, identifying a cluster having a lowest median intensity value from the one or more clusters; designating all locations within the identified cluster having the lowest median intensity value as a buried location; and reporting the buried location.
2. 2 . The method of claim 1 further comprising: adding an additional length of optical sensor fiber to the optical sensor fiber, identifying any additional buried locations; and reporting the additional buried locations.
3. 3 . The method of claim 1 comprising generating a baseline of buried locations.
4. 4 . The method of claim 3 comprising comparing the generated baseline with a newly identified buried location, and reporting the newly identified buried location when that newly identified location is not included in the baseline.
5. 5 . The method of claim 3 further comprising identifying buried locations that are exposed to a surface of ground and aerial cable touching the ground surface.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/341,446 filed May 13, 2022, the entire contents of which is incorporated by reference as if set forth at length herein. FIELD OF THE INVENTION This application relates generally to distributed fiber optic sensing (DFOS) systems, methods, structures and machine learning (ML) technologies. More particularly, it pertains to an efficient method of automated buried cable determination for cable status monitoring. BACKGROUND OF THE INVENTION It is of critical importance for telecommunications service providers to possess the ability to distinguish the locations—above or below ground—of sections of telecommunications facilities in a quick and reliable manner. Unfortunately, there exists no such acceptable method for determining the location(s) of underground (buried) cables. As such, telecommunications service providers must dispatch service personnel to perform in-person determinations, a time-consuming and expensive procedure. SUMMARY OF THE INVENTION An advance in the art is made according to aspects of the present disclosure directed to a distributed fiber optic sensing (DFOS) system and method that employs artificial intelligence/machine learning (AI/ML) methodologies to provide an integrated system and method providing real-time monitoring of an entire optical fiber cable route and distinguishes buried cable from aerial cables automatically and instantly (<1 min for a 25 km route). In sharp contrast to the prior art, systems, and methods according to aspects of the present disclosure provide for the autonomous determination of optical fiber cable location using AI/ML methodologies that advantageously: determines the buried sections of an optical fiber cable route; detects changes of status of the optical fiber cable route over time; wherein the AI/ML methodologies provide an automated operation; unsupervised—no manual labor is necessary when monitoring a new optical fiber cable route; no pre-training is required and no human annotation on data collection and classifiers training for each route separately; and is insensitive to field environmental conditions. BRIEF DESCRIPTION OF THE DRAWING FIG. 1(A) and FIG. 1(B) are schematic diagrams showing an illustrative prior art uncoded and coded DFOS systems; FIG. 2. Is a schematic diagram showing an illustrative operations of an automated buried cable determination according to aspects of the present disclosure; and FIG. 3 is a schematic diagram showing illustrative cable status monitoring application—normal vs. abnormal according to aspects of the present disclosure; FIG. 4 is a schematic flow diagram showing prior art workflow of existing, manual inspection and determination of optical fiber cable status; FIG. 5 is a schematic flow diagram showing illustrative workflow of the automated buried optical fiber cable detection and determination according to aspects of the present disclosure; FIG. 6 is a schematic diagram showing illustrative system setup according to aspects of the present disclosure; FIG. 7 is a series of plots illustrating median filter design for spatial smoothing of optical fiber data according to aspects of the present disclosure; FIG. 8 is a schematic diagram showing illustrative continuity detection compute the total number of buried sections according to aspects of the present disclosure; FIG. 9 is a schematic flow diagram showing illustrative data processing workflow of the automated buried optical fiber cable detection and determination according to aspects of the present disclosure; and FIG. 10 is a schematic diagram showing illustrative long-time monitoring of optical fiber cable status change for the automated buried optical fiber cable detection and determination according to aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION The following merely illustrates the principles of this disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are intended to be only for pedagogical purposes to aid the reader in understanding the principles of the disclosure and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function,