Improvements on quaternion-based iterative algorithms for attitude determination using GPS

In order to suppress strong measurement noise existing in the GPS attitude determination system in some practical situations, and to eliminate such effects on algorithms, a noise suppression method is suggested in the iterative procedure. To reduce the burden of calculation in this algorithm, the improved Broyden method is adopted. This method makes the estimations converge to the true value accurately even under strong noise. Improvements on reducing calculation burden also gives better results. Simulations showed the convergence errors caused by the noise to be smaller than was under former algorithms and the converging speed higher.