New algorithm for attitude determination using global positioning system signals

A novel technique for finding a point-by-point (deterministic) attitude solution of a vehicle using Global Positioning System phase difference measurements is presented. This technique transforms a general cost function into a more numerically efficient form by determining three-dimensional vectors in either the body or reference coordinate system. Covariance relationships for the new algorithm, as well as methods that minimize the general cost function, are also derived. The equivalence of the general cost function and transformed cost function is shown for the case of orthogonal baselines or sight lines. Simulation results are shown that demonstrate the usefulness of the new algorithm and covariance expressions.