In the WalkerConstellation class, the buildRegularSlots(O referenceOrbit) method builds all the constellation’s orbits according to the parameters passed in the constructor.
It would be useful to specify in the documentation that this method builds a Walker Delta constellation (ascending nodes are distributed over 360°).
It would also be interesting to be able to build a Walker Star constellation (ascending nodes distributed over 180°) for polar orbits.
… The Star pattern for WalkerConstellation is now implemented in Orekit develop branch 