Abstract: Aiming at the problem of maintaining the stability of Walker constellation in low Earth orbit (LEO), the factors affecting the orbit perturbation of LEO satellites and the stability of constellation configuration were analyzed. By analyzing the characteristics of the orbit perturbation and relative drift of the LEO Walker constellation, a two-bias strategy was proposed. First, the offset amount at the first offset was obtained by fitting the relative drift amount of the constellation when it was not offset. Then the relative drift after the first offset was used to obtain the second offset, eliminating the effects of residual terms. The two offsets were superimposed to greatly reduce the relative drift. The results show that the deviation of the initial parameters of the satellites in the LEO Walker constellation caused the divergence of the relative ascension of the ascending node and the relative drift of the along-track angle. The two-bias strategy can reduce the relative drift of the two constellations to less than 0.1°, which improves the effectiveness of the strategy and the stability of the constellation configuration.

Key words: LEO, Walker constellation, configuration maintenance, offset, stability