Calibration for star tracker with lens distortion

A new calibration model was proposed in the paper. Compared with traditional measurement models of star tracker containing principal points offset and focal length parameters only, the new model takes lens distortions into account. Lens distortions related mainly indicate radial distortion and tangential distortion. On the basis of the new measurement model, an easy autonomous calibration method, two-step method, based on least-squares method for star trackers is presented. In the first step, principal points, focal length, and attitude angle, were computed with distortion-free model using non-iterative least-square algorithm. In the second step the distortion parameters were estimated and all parameters were optimized by iteratively algorithm. Then synthetic attitude data and star catalog were adopted in the simulation. The results demonstrated that the proposed measurement model was accurate, and the calibration method of star tracker was available.