The utilization of a telescope with a large single aperture is limited by the manufacturing technique, cost, volume and
weight of a monolithic mirror. In order to solve these problems, the technology of the segmented synthetic aperture was
introduced. The primary mirror of a large segmented synthetic aperture telescope consists of several segmented mirrors,
whose misalignment errors make the wavefront change drastically and influence the MTF of the optical system badly.
The wavefront coding technology (WFC) is an innovative technology that joints the optical design and digital image
processing together. By adding a phase mask close to the pupil of an optical system and modulating the wavefront, the
WFC system becomes very insensitive to defocus and other aberrations based on defocus. The theoretical analysis of
characteristics of the WFC system was done in the form of PSF. The application of WFC to a segmented three mirror
anastigmat (TMA) was presented. A space telescope with an effective focal length as 40m, a F number as 10, a field of
view as 0.5°x0.05° was designed, whose primary mirror consisted of seven segmented mirrors. The influence of defocus
and misalignment errors on the telescope was discussed. The imaging process of the WFC system and following image
restoration were simulated. As a result, sharp images were obtained and the large segmented synthetic aperture telescope
had looser misalignment tolerance and extended depth of focus.