Security monitoring of an asset using distributed acoustic sensing with selected gauge lengths

A method for monitoring security of an asset for events which are potentially damaging or threatening to the asset, the method comprising:

• installing a continuous optical fiber continuously through the asset to be monitored;
• the asset having at least first and second zones where the continuous optical fiber passes through said first and second zones to define different portions of the continuous optical fiber each associated with a respective one of the first and second zones;
• wherein the asset is monitored by a perimeter monitoring system having said first and second zones using different installations of the continuous optical fiber in the first zone where the continuous optical fiber is installed on a fence adjacent the asset and in the second zone where the continuous optical fiber is installed in the ground at a location adjacent the asset;
• using a distributed acoustic sensing (DAS) interrogator to send signals into and receive data signals from the continuous optical fiber;
• effecting an analysis of the received data signals to determine the presence of an event in one or more of the zones;
• the analysis including assigning to the continuous optical fiber a series of sequential sliding windows where each sliding window has an associated gauge length parameter assigned thereto and analyzing the signals from each sliding window based on the gauge length assigned thereto;
• and selecting for the received data signals at the same time a first gauge length parameter for at least one sliding window in the first zone which is different from a second gauge length parameter for at least one sliding window in the second zone.

A method for monitoring security of an asset for events which are potentially damaging or threatening to the asset, the method comprising:

• installing a continuous optical fiber continuously through the asset to be monitored;
• the asset having at least first and second zones of different physical condition, environment and/or of different risk factors where the continuous optical fiber passes through said first and second zones to define different portions of the continuous optical fiber each associated with a respective one of the first and second zones;
• wherein the asset is monitored by a perimeter monitoring system having said first and second zones using different installations of the continuous optical fiber in the first zone where the continuous optical fiber is installed on a first fence adjacent the asset and in the second zone where the continuous optical fiber is installed on a second fence different from the first fence at a location adjacent the asset;
• using a distributed acoustic sensing (DAS) interrogator to send signals into and receive data signals from the continuous optical fiber;
• effecting an analysis of the received data signals to determine the presence of an event in one or more of the zones;
• the analysis including assigning to the continuous optical fiber a series of sequential sliding windows where each sliding window has an associated gauge length parameter assigned thereto and analyzing the signals from each sliding window based on the gauge length assigned thereto;
• selecting for the received data signals at the same time a first gauge length parameter for at least one sliding window in the first zone which is different from a second gauge length parameter for at least one sliding window in the second zone.

A method for monitoring security of an asset for events which are potentially damaging or threatening to the asset, the method comprising:

• installing a continuous optical fiber continuously through the asset to be monitored;
• the asset having at least first and second zones of different physical condition, environment and/or of different risk factors where the continuous optical fiber passes through said first and second zones to define different portions of the continuous optical fiber each associated with a respective one of the first and second zones;
• using a distributed acoustic sensing (DAS) interrogator to send signals into and receive data signals from the continuous optical fiber;
• effecting an analysis of the received data signals to determine the presence of an event in one or more of the zones;
• the analysis including assigning to the continuous optical fiber a series of sequential sliding windows where each sliding window has an associated gauge length parameter assigned thereto and analyzing the signals from each sliding window based on the gauge length assigned thereto;
• selecting for the received data signals at the same time a first gauge length parameter for at least one sliding window in the first zone which is different from a second gauge length parameter for at least one sliding window in the second zone;
• and changing at least one of the first and second gauge length parameters in response to changes in environmental or ambient conditions applied to the continuous optical fiber in at least one of the first and second zones.