the calibration method and procedure of the system are presented
the principle and composion of calibration system are also introduced. An analysis for the distortion of three-mirror off-axi is carried out on the basis of the distortion mathematically. The distortion is settled in the mathematical model by means of least square poly-regress method. The results show that calibration accuracy of the absolute distortion is less then 2μm(1σ)
and the calibration accuracy of relative distortion is less then 1×10-4(1σ). This method is fit for the request of high accuracy calibration of the distortion for three-mirror off-axis