An Image-Based Alignment Errors Correction Method for Segmented Fresnel Primary Mirror

Abstract

The alignment errors correction of segmented Fresnel primary mirror in multiple imaging scenes is simulated. Based on the linear relationship between five kinds of alignment errors and modulation transfer function metric or image frequency domain metric, an iterative correction method is introduced to compensate the alignment errors of segmented Fresnel lens at five degrees of freedom. The correction capability under point target imaging and the effect of alignment error correction under extended target imaging are studied. The simulation results show that the proposed correction scheme can effectively correct the alignment error when the rms value of segmented Fresnel primary mirror is less than 0.7λ. This method does not need to add any additional devices to the telescope, but optimizes directly based on the images, and is independent of the spatial structure of the imaging target. It may be suitable for fine phasing correction of segmented membrane diffractive optical telescope in orbit.

Keywords

• Segmented membrane telescope
• alignment errors
• fine phasing correction