Characterisation of Raman distributed temperature sensor using deconvolution algorithms

The behaviour of distributed temperature sensors based on spontaneous Raman scattering using deconvolution algorithm is studied for improvement of temperature and spatial resolution in Raman distributed temperature sensor (RDTS). The deconvolution algorithms such as Fourier deconvolution (FourD), Fourier regularised deconvolution and Fourier wavelet regularised deconvolution (FourWaRD) are investigated in this study. Numerical simulation shows that the temperature resolution is enhanced by six times using the proposed FourWaRD algorithm compared with conventional FourD algorithm. In this study, for a light source with 60 ns pulse width, a spatial resolution of 3 m is achieved using the FourWaRD algorithm. The proposed sensing system exhibits a temperature resolution of 0.45 K because of the reduction of noise. In addition, the signal to noise ratio (SNR) of proposed RDTS is realised using Indium Gallium Arsenide avalanche photo detector over a 30 km sensing range. The authors have achieved about 4 dB improvement of SNR using FourWaRD algorithm compared with FourD algorithm at a distance of 25 km for an input power of 10 dBm. The numerical simulation results indicate that the proposed deconvolution algorithms are beneficial complements for RDTS to realise accurate detection and temperature monitoring of sharp temperature variations.