Abstract:In order to solve the problem of calculating the orbit parameters with elliptic parameters fitted by partial edge point in the target image in optical navigation (sphere), a direct projection model of orbit parameters mapped by edge points is proposed to avoid the fitting of parameters. Based on the pinhole imaging model, the direct projection mathematical model of the edge points and the orbit parameters is established. The orbit direct projection model is theoretically deduced. And the Levenberg-Marquard algorithm is used to obtain the orbit parameters. The simulation results show that the orbit accuracy can reach 5‰ under the same edge points. Compared with the traditional method, this method avoids the ellipse fitting process and reduces the intermediate error process.