Spanos, Pol D.2013-09-162013-09-162013-09-162013-09-162013-052013-09-16May 2013Ainscough, Thomas. "Spacecraft Attitude Estimation Integrating the Q-Method into an Extended Kalman Filter." (2013) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/71913">https://hdl.handle.net/1911/71913</a>.https://hdl.handle.net/1911/71913A new algorithm is proposed that smoothly integrates the nonlinear estimation of the attitude quaternion using Davenport's q-method and the estimation of non-attitude states within the framework of an extended Kalman filter. A modification to the q-method and associated covariance analysis is derived with the inclusion of an a priori attitude estimate. The non-attitude states are updated from the nonlinear attitude estimate based on linear optimal Kalman filter techniques. The proposed filter is compared to existing methods and is shown to be equivalent to second-order in the attitude update and exactly equivalent in the non-attitude state update with the Sequential Optimal Attitude Recursion filter. Monte Carlo analysis is used in numerical simulations to demonstrate the validity of the proposed approach. This filter successfully estimates the nonlinear attitude and non-attitude states in a single Kalman filter without the need for iterations.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Attitude estimationNonlinear estimationExtended Kalman filterWahba problemThesis2013-09-16123456789/ETD-2013-05-543