Telecom cable tension screening technique based on wave propagation and distributed acoustic sensing
A radio-controlled, two-way acoustic modem for operating with a distributed fiber optic sensing (DFOS) system including circuitry that receives radio signals including configuration information, configures the modem to operate according to the configuration information, and generate acoustic signals that are detected by the DFOS system. The acoustic modem includes one or more sensors that detect environmental information that is encoded in the acoustic signals for further reception by the DFOS system. The received configuration information may change the operating times, sensors or other operating aspects of the modem as desired an such information may be transmitted from a fixed location or a mobile vehicle.
1. A telecommunications cable tension screening method using wave propagation and distributed fiber optic sensing/distributed acoustic sensing (DFOS/DAS), the method comprising:
providing a distributed fiber optic sensing/distributed acoustic sensing (DFOS/DAS) system including
a length of optical sensor fiber, at least a portion of which is suspended from a plurality of utility poles;
an optical interrogator in optical communication with the length of optical sensor fiber, the optical interrogator configured to generate optical pulses, introduce the generated optical pulses into the length of optical sensor fiber and receive backscattered signals from the optical sensor fiber;
an analyzer configured to collect and analyze the backscattered signals, generate waterfall images to determine utility pole localization, and determine vibration wave speed of vibrations propagating in the optical sensor fiber and determine a tension force of the optical sensor fiber;
operating the DFOS/DAS while providing mechanical impacts to a plurality of the utility poles;
generating color waterfall images from backscattered signals resulting from the mechanical impacts;
determining a location along the length of the optical sensor fiber at which a utility pole receiving mechanical impacts is located;
determining a wave speed of vibrations propagating in the optical sensor fiber resulting from the mechanical impacts; and
determining a tension force of the optical sensor fiber.
2. The method of claim 1 further comprising applying a Canny edge detection operation to the color waterfall images generated from backscattered signals resulting from the mechanical impacts.
3. The method of claim 2 further comprising converting the color waterfall images to greyscale images.
4. The method of claim 3 further comprising applying a Gaussian blur with image convolution to smooth the greyscale images.
5. The method of claim 4 further comprising determining the wave speed of the vibrations propagating in the optical sensor fiber from the smoothed greyscale images and determining the tension force in the optical sensor fiber from the determined wave speed.