Rolling Shutter Distortion Modeling and Corrective Algorithm for Agility Improvement of Star Sensors

Agile satellites are recent trends for Earth observation, imaging, security, and remote sensing applications. The target and location accuracy of it is governed by its star sensor, which provides absolute attitude to the platform. The challenge imposed on the image processing of star sensor is to achieve high-accuracy star imaging while the satellite is under angular motion for Earth observations. The recent imaging detectors, active pixel sensor detectors, with lower readout noise, capture sky images using an electronic rolling shutter frame. Although it provides better noise performance compared with a global shutter, it causes additional distortion of star positions under high angular rate of the satellite. This letter is focused on developing a mathematical model of rolling shutter distortion in star sensor system by analyzing its kinematics and detector readout method. One of the challenges in rolling shutter correction is nullifying the effect of acceleration and studying its residual effects. A star sensor-specific approach is also proposed to correct the distortion to achieve the arc-sec-order accurate attitude information. This letter also presented simulation results for angular rates up to 10°/s and acceleration up to 5°/s
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and the results of a practical demonstration.