High-Precision large deformation measurement of array SAR based on FBG strain monitoring and initial state reconstruction

Array Synthetic Aperture Radar (SAR) as the novel generation airborne remote sensing system is installed below the wing, has received more attention because it can realize all-weather three-dimensional (3-D) imaging. Its high-precision imaging needs to measure large deformation of wing accurately. The exiting methods based on Fiber Bragg grating (FBG) sensors ignore the effects of wing initial state, which will generate non-negligible nonlinear measurement error. To solve this problem, a high-precision large deformation measurement method of array SAR based on FBG strain monitoring and initial state reconstruction is proposed. Firstly, initial angle reconstruction approach is presented to obtain initial state. Then, bending strain measurement method is used to obtain continuous strain. Finally, large deformation model based on initial angle and bending strain is established to achieve large deformation. Experimental results indicate proposed method can effectively measure large deformation, and can acquire the higher displacement accuracy compared to traditional method.