The purpose of the research is to establish a calibration method for antenna pointing, which has difficulty in observing stars except the sun because of its low cost but noisy receiver, nor has its own calibration system. Two approaches are suggested in this paper. First method is the estimation of the target direction using the received signal. This is real time estimation, using Unscented Kalman Filter based on Cross-Scan method. Second is off-line estimation, which calculates coordinate of antenna using the result of the real time estimation. The first method was tested by simulation and the experiment tracking the sun. It was found that antenna will be able to track the sun for more than 4 hours autonomously. In the experiment, Φ3m parabola for Nano-JASMINE, nano-satellite for astrometry being developed by National Astronomical Observatory of Japan, the University of Tokyo, was used. The second method was tested by simulation and it was indicated that the pointing error would be less than 0.3degree.