Minimal-Parameter Attitude Matrix Estimation from Vector Observations

A computationall y efficient, sequential method is presented for attitude matrix estimation using gyro and vector measurements. The method is based on a recently introduced, minimal-parameter third-order method for solving the orthogonal matrix differential equation. A nonlinear algorithm is developed, which uses a minimal set of three parameters to estimate the nine-parameter direction-cosine matrix. An orthogonali/a tion procedure, incorporated into the measurement processing stage, enhances the accuracy and stability of the resulting algorithm, yet retains reasonable simplicity. The performance of the estimator is demonstrated via a numerical simulation study.