Traditional in-orbit imaging performance calibration of optical imaging satellite is always based on the sun or
ground artificial target. As imaging system performance advancing, the calibration procedure could base on
fainter target such as stars instead. The practical step of star-based satellite performance calibration procedure
is to select proper stars according to their magnitude and spectral character, center them in image by image
processing, and transform the image to achieve imaging MTF. Nowadays space-based camera with large
aperture could transfer photoelectrons continuously to obtain enough long exposure duration, so faint stars
can also be detected. But the center of star would always tilt from the center of detector pixels which would
be very hard to align. With Discrete Fourier Transformation (DFT) and Point Source Function (PSF)
correlation, the align accuracy could be improved observably. Finally, as a complex imaging system, the final
image MTF would also includes defocus effect and satellite platform jitter etc, which the defocus is of circular
shape and temporal independentCbut the jitter is of linear type in short exposure and the direction and length
may be a function of time. So based on a time serial images and the iteration algorithm, the jitter characteristic
may be separated. Simulation calibration procedure mentioned above indicates satisfying consequence. So
those calibration outcomes could also be used to determine the defocus of the focal plane in camera and the
high frequency jitter of the satellite platform during exposure duration while imaging.
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