Tightly-coupled MEMS-INS/GPS Integration Using Sequential Processing Method

The delta pseudorange measurement is often used in INS/GPS tightly-coupled integration for velocity determination. However, it is a type of integrated measurements with errors strongly related to the pseudorange errors at the beginning and end of the integration interval. In order to correctly account for these errors, in this paper, we carry the delayed state terms to remember the estimation errors of the pseudorange at the beginning of the integration interval. Besides, sequential processing is used in the measurement update of the Kalman filter (KF) algorithm to prevent the matrix inverse calculation. Simulations are conducted on the basis of a field collected 3D UAV trajectory. Numerical results show that the correct handling of the errors involved in the delta pseudorange measurements is critical, especially when the vehicle is maneuvering under high dynamics.