RT info:eu-repo/semantics/article
T1 Analysis and reduction of large errors in Rayleigh-based distributed sensor
A1 Li, Zhang
A1 Pereira da Costa, Luis Duarte
A1 Zhisheng, Yang
A1 Soto Hernández, Marcelo Alfonso
A1 González Herráez, Miguel
A1 Thévenaz, Luc
K1 Fiber optics
K1 Fiber optics sensors
K1 Rayleigh scattering
K1 Electrónica
K1 Electronics
AB Commonly, the frequency shift of back-reflection spectra is the key parameter to measure quantitatively local temperature or strain changes in frequency-scanned Rayleigh-based distributed fiber sensors. Cross correlation is the most common method to estimate the frequency shift; however, large errors may take place, particularly when the frequency shift introduced by the temperature or strain change applied to the fiber is beyond the spectral width of the main correlation peak. This fact substantially limits the reliability of the system, and therefore requires careful analysis and possible solutions. In this paper, an analytical model is proposed to thoroughly describe the probability of large errors. This model shows that the cross correlation intrinsically and inevitably leads to large errors when the sampled signal distribution is finite, even under perfect signal-to-noise ratio. As an alternative solution to overcome such a problem, least mean squares is employed to estimate the frequency shift. In addition to reducing the probability of large errors, the proposed method only requires to measure a narrow spectrum, significantly reducing the measurement time compared to state-of-the-art implementations. Both the model and the solution are experimentally verified using a frequency-scanned phase-sensitive optical time-domain reflectometry system, achieving a spatial resolution of 5 cm, with a sensing range of 860 m and an acquisition time below 15 s, over a measurable temperature range of more than 100 K with a repeatability of 20 mK, corresponding to a temperature dynamic range of 5000 resolved points.
SN 0733-8724
YR 2019
FD 2019-09-15
LK http://hdl.handle.net/10017/39529
UL http://hdl.handle.net/10017/39529
LA eng
NO European Commission
DS MINDS@UW
RD 20-abr-2024