A Non-singular Attitude Filtering Based On UKF Using Modified Rodrigues Parameters

Modified Rodrigues Parameter(MRP) is a method to estimate attitude. Previous work which used MRP based on EKF has a disadvantage that can be only used in a range which MRP vector behaves nearly linearly. This article provides a MRP based on UKF to break the constraint make it possible to reduce the transformation times between MRP and shadow MRP. Plus, UKF MRP has an advantage of smaller amount of calculation which naturally contributes to a more complete theoretical derivation of MRP. In example problem part, UKF MRP is used to solve an INS and GPS system's attitude estimation problem and the MRP filter formulation based on UKF and linear EKF MRP is compared with USQUE.