Abstract: The phase maintenance method is introduced for a nearcircular LEO satellite constellation without orbital altitude maintenance requirements in this paper. According to the orbit perturbation theory, the satellite phase drift model considering J2 perturbation and atmospheric drag perturbation is derived, and then two expression methods of phase deviation based on fixed reference satellite and virtual reference satellite are given respectively. On this basis, the theoretical and practical control quantity considering actual control errors are given for the two cases of orbit decay rate consistent and inconsistent. Finally, the effectiveness of the two methods are verified by a LEO Walker constellation simulation example. The results show that the two methods can effectively complete the phase maintenance task. The two methods have no significant difference in the number of times of control and the total amount of control in the case of orbit decay rate consistent. But in the case of orbit decay rate inconsistent, the phase maintenance strategy based on a fixed reference satellite is better.

Key words: satellite constellation, phase maintenance, reference satellite, orbit decay