MINIMAL-PARAMETER ATTITUDE MATRIX ESTIMATION FROM VECTOR OBSERVATIONS

A computationally efficient, sequential method is presented for attitu de 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 in R-n. In the three-dimensional case, these third order attitude parameters can be interpreted as temporal integrals of the body-frame angular velocity c omponents. A nonlinear algorithm is developed, which uses this minimal set of three parameters to estimate the nine-parameter direction-cosi ne matrix. Having an extremely simple kinematic equation, these parame ters render the resulting estimator highly computationally efficient. An orthogonalization procedure, incorporated into the measurement proc essing stage, enhances the accuracy and stability of the resulting alg orithm, yet retains reasonable simplicity. The performance of the new estimator is demonstrated via a numerical simulation study.