Spacecraft synchronization in the presence of attitude constrained zones

In this paper, we consider the problem of achieving identical orientation for a group of spacecraft in presence of attitude forbidden zones. The attitude forbidden zones can be identically defined over the group of spacecraft or can be defined independently. In order to find a feasible consensus-like algorithm, we utilize the quadratic convex parameterization for the attitude forbidden zones with unit quaternions. Subsequently, we embed this parameterization into a convex auxiliary system-whose output is shared among the spacecraft through a communication network. The auxiliary system´s output play the role of an indicator function for the spacecraft dynamics such that it does not violate the attitude forbidden zones while attempting to reach consensus. In order to evaluate the effectiveness of the algorithm, we present two sets of simulations where synchronization of six spacecraft with identical and independent attitude forbidden zones with random initial attitudes are considered.