提高光纤光栅传感器测量精度的研究

Method for improving measurement precision of fiber Bragg grating sensor

在实际应用中,光纤光栅传感器的测量精度受到噪声、成本等因素的制约。为了实现低成本的高精度光纤光栅传感器系统,提出了对光纤光栅反射谱采用自适应阈值小波消噪和B样条拟合算法的处理技术,并通过实验和仿真得出自适应阈值小波消噪,有效提高了系统的信噪比,在相同采样精度下拟合处理前波长检测的误差为0.01nm,处理后为0.0017nm,误差降低了一个数量级。实验结果证明该方法不但可以有效降低噪声带来的读取误差,而且提高了测量Bragg波长漂移量的分辨率,从而实现高精度测量温度、应变等外界参量。

In practice,the measurement precision of fiber Bragg grating sensor is limited by noise,cost and other factors.In order to achieve low-cost and high-precision fiber Bragg grating sensor system,a method is proposed which uses adaptive threshold wavelet denoising and B-spline fitting algorithm on the fiber Bragg grating reflection spectrum.Two results are obtained by experiment and simulation.One is that adaptive threshold wavelet denoising can effectively improve SNR of the system.The other is that the error of the wavelength testing is 0.01 nm before fitting and 0.0017 nm after fitting under the same sampling precision and error is lowed about an order of magnitude.Experimental results prove that the method can effectively reduce reading errors caused by noise,and improve the resolution for measurement of fiber Bragg grating wavelength shift in order to achieve high-precision measurement of temperature,strain and other external parameters.