The main idea of autonomous navigation based on velocity measurement is to detect the on-sight speed of the star in the space when the satellite sees it using the spectrograph. The Sun is one of the most important observation targets in space. In this paper, we analyze the data of the space-born spectrograph to observe the Sun at five different positions. Each data set has a period of about one hour. Using the Gaussian profile fitting, we can get the intensity, width and speed. The mean speed is about 10 km/s with a standard deviation of 3 km/s, which is caused by the small scale activities on the solar surface.