SYSTEM AND METHOD FOR MONITORING OF AN OBJECT/STRUCTURE BY MEASUREMENT OF VIBRATIONS USING AN OPTICAL FIBER

• Main Authors: CARMINATI, Stefano, ZAMPATO, Massimo, PALMIERI, Luca, TUROLLA, Axel
• Format: Patent
• Language: English; French; German
• Published: 31.07.2024
• Subjects: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC ORINFRASONIC WAVES; MEASURING; PHYSICS; TESTING

System (1) and method for monitoring by optical fiber (3) for the measurement of vibrations an object /structure (2). The system comprises the optical fiber (3) associated with the object/ structure (2) and having one end connected to a circulator (4) and a terminated opposite end, a source (5) of symbols emitting sequence of NS input signals (σ i= [0,..,NS- 1] ) and which is configured to generate an input vector (s (τ) ) with Nc input signals (Sn (τ) n= [0,..,Nc-1] ), a multi-carrier OFDM modulation block (6) adapted to modulate a light beam (13) emitted by a laser source (12) by means of an OFDM modulating signal to determine a sensing signal (s IN (t)) with Nc subcarriers, said modulating signal OFDM being generated on the basis of the input vector (s(τ) ); the circulator (4) being adapted to send the sensing signal (s IN (t)) to the optical fiber (3) and to receive a backscattered signal SOUT (t); an OFDM demodulation block (19) which receives a second light beam of intensity proportional to said light beam (13) to demodulate the backscattered signal (SOUT (t)) determining an output vector (u(τ) ) with Nc output signals (un(τ) n= [0,..,Nc-1] ) which include backscattered symbols; a processing unit (20) that processes the output vector (u(τ)) and the input vector (s(τ)), on the basis of respective Nc reference vectors (R- n n= [ 0,.., Nc 1] ) of said optical fiber (3), generating a deformation vector (V(T)) of said optical fiber (3), said Nc reference vectors (R- n n=[0,..,Nc-1] ) being determined considering unperturbed conditions of said optical fiber (3).