ATTITUDE DETERMINATION USING VECTOR OBSERVATIONS - A FAST OPTIMAL MATRIX ALGORITHM

The attitude matrix minimizing Wahba's loss function is computed direc tly by a method that is either faster or more robust than any previous ly known algorithm for finding this optimal estimate. Analysis of the special case of two vector observations identifies those cases for whi ch the TRIAD or algebraic method minimizes Wahba's loss function. The new method also provides an estimate of the attitude error covariance matrix, including an especially convenient representation of the two-o bservation covariance matrix.