Shanghai Institute Of Optics And Precision Machinery (SIPM) Makes Progress in Long-distance Acoustic Fiber Optic Cable Attitude Sensing Technology Based On Distributed Acoustic Wave Sensing

Recently, a team from the Department of Space and Astronautical Laser Technology and Systems, Shanghai Institute of Optical Precision Machinery (SIPM), Chinese Academy of Sciences (CAS), and the Key Laboratory of Space Laser Information Transmission and Detection Technology (KLTIDT), CAS, has proposed a long-range acoustic-sensitive fiber optic cable attitude sensing method based on distributed acoustic wave sensing (DAS), which provides a new idea for the oceanic distributed hydrophone trailing array array calibration, and the detection of the shapes of large-size structures. The related research results are published in Optics Letters under the title Distributed shape detection for an acoustic sensitive optical cable with DAS.
Acoustic sensitive optical cable plays an increasingly important role in marine applications such as hydroacoustic detection and target localization, but its attitude changes continuously under the effect of water current and carrier motion, which brings great difficulties to hydroacoustic enhancement and array processing. Therefore, it is of great significance to realize the attitude sensing of long-distance acoustic fiber optic cable.
The research team proposes a long-distance acoustic fiber optic cable attitude sensing technique based on DAS. Using the known position of the auxiliary sound source array, accurately obtain the positional relationship between each fiber optic cable unit and the auxiliary sound source array, and put forward adaptive peak-seeking algorithm to solve the problem of peak distortion of acoustic reverberation in the actual environment; give full play to the DAS is easy to large-scale networking, array can be flexibly reconfigured, and other unique advantages, to get the real-time attitude of the entire acoustic sensitive fiber optic cable. Validation experiments show that the technology can realize the attitude sensing of sound-sensitive fiber optic cable under air environment, and the three-dimensional positioning accuracy is 6.53 cm. The results provide a new type of structural attitude sensing method, which has the advantages of large applicable structure size, high detection density, convenient and flexible deployment, and is expected to solve the difficult problems of towed array attitude correction, which will play an important role in the field of hydroacoustic sound detection, marine safety and other fields.
The relevant research has been supported by the National Natural Science Foundation of China, the Shanghai Qi-Star Program, and the Chinese Academy of Sciences Youth Innovation Promotion Association.

Figure 1 Schematic diagram of the principle

Fig. 2 (a) Single-point high-precision localization results (b) U-shaped cable shape detection results