Encke methods adapted to regularizing variables

In this paper formulations of Encke's type corresponding to the best known sets of linearizing coordinates KS and BF are presented. They are easier to derive than the usual formulation in Cartesian variables, since no numeric al difficulties appear in the equations of motion. The experiments performe d show a remarkably good behavior of the new methods for the numerical inte gration of satellite orbits, the performance of the classic version being c learly improved, at least in the analyzed cases corresponding to nearly cir cular low Earth orbits. Some questions concerning the possibility of increa sing the accuracy by means of rectifications are briefly treated. Moreover our methods are proved to be able to compete with the corresponding methods in linear KS or BF elements.