基于光纤传感的航天器结构应变参数精确测量

为实现空间高低温环境下航天器结构应变参数的精确测量，采用基于法布里–珀罗（Fabry-Perot, F-P）标准具和乙炔（C2H2）气室的复合波长参考的光纤测量方法，对可调谐滤波器透射波长进行校正，以保证解调精度。在解调过程中，采用自适应阈值法解决光源平坦度差引起的F-P标准具寻峰困难问题，并且基于时间预测性最大化原理对透过气室的光源信号进行盲分离，以提高气室波长校正精度。实验结果表明，该方法可实现在高低温环境下光纤传感器中心波长解调偏差小于3 pm，结构应变测量相对误差小于4%，能够满足实际工程应用中航天器结构应变参数的高精度测量需求。

Accurate measurement of strain parameters of spacecraft structure based on optical fiber sensing

In order to achieve a high accuracy measurement of the strain parameters of the spacecraft structure with optical fiber sensors, in the space environment of high and low temperatures, a demodulation approach with a composite wavelength reference is adopted, with the Fabry-Perot(F-P) etalon and the acetylene(C2H2) gas cell being used together to calibrate the transmission wavelength of the tunable filter. An adaptive threshold method is adopted to improve the peak finding process of the F-P etalon in spite of the flatness of the light source. Meanwhile, the light source signal passed through the gas cell is separated blindly based on the principle of the time prediction maximization, so as to improve the precision of the wavelength calibration for the gas cell. It is shown that the deviation of the wavelength demodulation with the above approach is less than 3 pm in the temperature scope of -25 ℃ to 60 ℃, and the relative measurement error of the structure strain is less than 4%. With this method, the requirement of the accurate measurement of the strain parameters for spacecraft structures can be satisfied in various engineering applications.