US 12,360,004 B2
Monitoring optical fibers with false alarm suppression using dissimilar algorithms
Cary R. Murphy, Hickory, NC (US); Daniel M. Goertzen, Winnipeg (CA); and Mark K. Bridges, Hickory, NC (US)
Assigned to Network Integrity Systems, Inc., Hickory, NC (US)
Filed by Network Integrity Systems, Inc., Hickory, NC (US)
Filed on Oct. 14, 2022, as Appl. No. 17/966,120.
Prior Publication US 2024/0125671 A1, Apr. 18, 2024
Int. Cl. G01P 5/02 (2006.01); G01H 9/00 (2006.01); G01M 11/08 (2006.01); G01W 1/14 (2006.01); G08B 13/186 (2006.01); G08B 21/18 (2006.01); G08B 29/18 (2006.01); G01D 5/353 (2006.01); G01M 11/00 (2006.01); G01W 1/00 (2006.01); G08B 13/12 (2006.01)
CPC G01M 11/088 (2013.01) [G01H 9/004 (2013.01); G08B 21/182 (2013.01); G01D 5/35361 (2013.01); G01M 11/3109 (2013.01); G01P 5/02 (2013.01); G01W 2001/006 (2013.01); G01W 1/14 (2013.01); G08B 13/124 (2013.01); G08B 13/186 (2013.01); G08B 29/18 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for monitoring an optical cable containing at least one optical fiber for disturbance events of the optical cable comprising:
in a first monitoring system, introducing a monitoring optical signal into said at least one optical fiber;
receiving optical signals from said at least one optical fiber which are modified by disturbance events on said at least one optical fiber;
wherein the optical signals are divided into a plurality of data streams, where each data stream is associated with a specific respective portion of said at least one optical fiber with the portions divided along the length of said at least one optical fiber so that each data stream is indicative of a disturbance event of a plurality of disturbances in the respective portion and therefore of the disturbance event in said at least one optical cable at the respective portion;
wherein in the first monitoring system comprises a Distributed Sensing system such as DAS where the optical signals from said at least one optical fiber are backscattered signals which are divided into said plurality of data streams;
wherein each data stream comprises a series of data values representative of the plurality of disturbances over time in the respective portion;
applying a first detection algorithm to the data and using the first detection algorithm applied to the data streams to generate a first output indicative of the disturbance event;
in a second monitoring system introducing a second monitoring optical signal into said at least one optical fiber;
receiving optical signals from said at least one optical fiber which are modified by disturbance events on said at least one optical fiber;
wherein the second monitoring system comprises a zone monitoring system which is responsive to optical signals received from a plurality of selected lengths of said at least one optical fiber defining a plurality of monitoring zones which are modified by said disturbance events in said plurality of monitoring zones of said at least one optical fiber and form a single stream of data from each of said zones;
applying a second detection algorithm to the received optical signals and using the second detection algorithm applied to the received optical signals to generate a second output indicative of the disturbance event;
and in a control system using information from the first and second outputs to determine if an alarm should be issued.