Detection system, detection method, and analysis device

A detection method for detecting a linear structure, using an optical fiber cable including a multi-core optical fiber and having different cross sectional lengths in a vertical direction and a horizontal direction, the detection method comprising:

• measuring a strain distribution along an extending direction of the multi-core optical fiber before the optical fiber cable is installed into the linear structure, by using a strain distribution measurement device,
• measuring a strain distribution along an extending direction of the multi-core optical fiber after the optical fiber cable is installed into the linear structure, by using the strain distribution measurement device, and
• calculating the shape of the optical fiber cable using a difference between the strain distribution before the optical fiber cable is installed and the strain distribution after the optical fiber cable is installed, and calculating an installation position of the linear structure based on the shape of the optical fiber cable, by using an analysis device.

An analysis device, using an optical fiber cable including a multi-core optical fiber and having different cross section lengths in a vertical direction and a horizontal direction, the analysis device comprising:

• a reception unit, including one or more processors, configured to receive a strain distribution along an extending direction of the multi-core optical fiber measured before the optical fiber cable is installed into the linear structure, and to receive a strain distribution along an extending direction of the multi-core optical fiber measured after the optical fiber cable is installed into the linear structure, and
• an arithmetic unit, including one or more processors, configured to calculate a shape of the optical fiber cable using a difference between the strain distribution before the optical fiber cable is installed and the strain distribution after the optical fiber cable is installed, and to calculate an installation position of the linear structure based on the shape of the optical fiber cable.