An S-transform-Based Positioning Method for Asymmetric Interferometer Disturbance Sensors

To effectively eliminate the influence of the asymmetric structure on the positioning accuracy of asymmetric interferometer disturbance sensors, this paper proposes a positioning method based on convolution window filtering (CWF) and the S-transform (ST). First, we employ the CWF method to remove the noise and detect the endpoint of a disturbance frame, which is permanently stable. Then, the ST-based algorithm is used to remove the asymmetry of the extracted signal, which would seriously reduce the positioning accuracy. Finally, an experiment is performed to verify the effectiveness of this scheme by employing an asymmetric dual-laser source Mach-Zehnder interferometer based sensing system. The experimental results demonstrate that 93.25% of the positioning errors of 800 set tests are distributed in the range of ±20 m at the sensing length of 101 km. The average processing time of 800 set tests is 0.21 s. Therefore, the proposed method has practical applications in the field of perimeter security.