Aas 13-836 Quaternion Based Optimal Spacecraft Reorientation under Complex Attitude Constrained Zones

The paper addresses quaternion-based energy and time optimal spacecraft reorientation in the presence of complex attitude constrained zones. Designing an optimal reorientation trajectory for a rigid body spacecraft is posed as a nonlinear optimal control problem. In this direction, attitude constrained zones are defined with respect to the onboard instrument under two categories, forbidden and mandatory zones. These zones are parameterized as quadratic inequality constraints in unit quaternions. The optimal control problem is then solved using a Gauss pseudospectral method. Ambiguity on geodesic/non-geodesic rotations which is a consequence of the quaternion formulation, is discussed and a novel algorithm is presented for its treatment. The paper concludes with extensive simulation results including typical scenarios many science mission spacecraft face as well as more complex scenarios in order to demonstrate the viability of the proposed methodology.