Time synchronization method with trusted beacons and distributed fiber sensing

A method for distributed fiber optic sensing (DFOS) systems comprising:

• providing a DFOS system including
• a length of optical sensor fiber;
• an optical interrogator configured to generate optical pulses, introduce the generated optical pulses into the optical sensor fiber, and receive backscattered optical signals in response to the introduced optical pulses;
• and
• an analyzer that analyzes the backscattered optical signals and determines vibrational activity occurring at locations along the length of the optical sensor fiber;
• providing a plurality of beacons at a respective plurality of locations along the length of the optical sensor fiber, the plurality of beacons including
• vibrators configured to generate mechanical vibrations;
• and
• wireless transceivers configured to transmit and receive wireless signals;
• wherein the plurality of beacons generate mechanical vibrations, such vibrations are detected by the DFOS system.