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Group alternating integration for distributed acoustic sensing with improved signal-to-noise ratio

Angelsky Oleg, Strynadko Myroslav, Zenkova Claudia, Zheng Jun

Opto-Electronics Review

2025

Vol. 33, No. 4

art. no. e155878

Distributed acoustic sensing (DAS) based on Rayleigh backscattering is actively used for perimeter monitoring of critical infrastructure. However, traditional signal processing methods often face challenges in detecting weak or short-term events in noisy conditions. In this paper, we propose an improved signal accumulation method based on group averaging with alternating sign integration. The proposed method provides the efficient noise suppression and improves the detection of local mechanical disturbances along the fibre. Comparative simulation study between the classical and the proposed approach demonstrates a significant improvement in signal visibility in the presence of additive noise. Potential implementations of multi-layered and mesh-integrated DAS configurations are also discussed to further enhance signal-to-noise ratio (SNR). The obtained results can serve as a basis for the development of modern security systems for critical facilities.

A high performance distributed sensor system with multi-intrusions simultaneous detection capability based on phase sensitive OTDR

Zhan Y., Yu Q., Wang K., Yang F., Kong Y., Zhao X.

Opto-Electronics Review

2015

Vol. 23, No. 3

187-194

A high performance distributed sensor system with multi-intrusions simultaneous detection capability based on phase sensitive OTDR (Φ-OTDR) has been proposed and demonstrated. To improve system performance, three aspects have been investigated. Firstly, a model of one-dimensional impulse response of backscattered light and a Monte Carlo method have been used to study how the laser line width affects the system performance. Theoretical and experimental results show that the performances of the system, especially the signal-noise-ratio (SNR), decrease with the broadening of laser linewidth. Secondly, a temperature-compensated fibre Bragg grating with a 3 dB linewidth of 0.05 nm and a wavelength stability of 0.1 pm has been applied as an optical filter for effective denoising. Thirdly, a novel interrogation method for multi-intrusions simultaneous detection is proposed and applied in data denoising and processing. Consequently, benefiting from the three-in-one improvement, a high performance Φ-OTDR has been realized and four simultaneous applied intrusions have been detected and located at the same time along a 14 km sensing fibre with a spatial resolution of 6m and a high SNR of 16 dB. To the best of our knowledge, this is the most multifunctional Φ-OTDR up to now and it can be used for perimeter and/or pipeline intrusion real-time monitoring.