The influence of co-phasing error on image quality in synthesized aperture telescope

In this paper, an active co-phasing and aligning synthesized aperture imaging system with three quasi-annulus-sectors segmented mirrors was analyzed. The influence of co-phasing error, especially piston error, on image quality of the synthesized aperture imaging system was studied. The relationship of the Point Spread Function (PSF) and piston errors between the adjacent segments was deduced theoretically within the coherence length of the source. According to this theoretical model, the influence of piston error on the image quality in the synthesized aperture imaging system was known that the PSF changes with the variation of piston error. And more importantly, the cycle of this change is λ/2 (λ is the wavelength of the source) when a certain piston error is introduced between two adjacent segment. Additionally, simulation model of the three segmented synthesized aperture imaging system was set up by ZEMAX and simulation experiments have been carried out to verify the conclusion derived from the theory model deduced above. The results show that the simulation experiments results consistent with the theoretical conclusion deduced above. The results provide theoretical foundation for further study and actual reference of tolerance for a synthesized aperture telescope design and manufacture.