Geometric calibration of the linear-array whiskbroom optical satellites based on look-angle corrections

Abstract

Linear-array whiskbroom optical satellites are equipped with scanning mirrors and compensation mirrors. They rotate and scan imaging with the satellite flight orbit as the rotation axis, and geometrically splice the scanned images along the orbit, achieving a balance between large width and high resolution of remote sensing images. The addition of scanning mirrors and compensation mirrors necessitates multiple reflections for the imaging ray to reach the focal plane. Hence, the calibration of the geometric aspects for linear-array whiskbroom optical satellites will be an intricate procedure. A geometric calibration model based on look-angle corrections is established according to the imaging characteristics of linear-array whiskbroom optical satellites. All errors are corrected using correction quantities, and cubic polynomial surfaces are used to fit correction quantities. The proposed geometric calibration method based on the look-angle corrections has a sensor positioning precision of better than 1.0 pixels for the calibrated image.