Abstract: This paper describes the design and implementation of an integrated MEMS IMU and two-antenna GPS system for artillery vehicles. The two-antenna GPS is developed to accurately estimate the vehicle azimuth, and the integrated IMU/GPS provides attitude, position and velocity. To ensure numerical stability and real-time navigation, the faster Kalman filter based on UD factorization is presented in this paper. This research is aimed at producing a low-cost navigation system for artillery vehicles. Thus, an inexpensive solid-state MEMS IMU is used. A prototype system is built and tested, and testing results are given in this paper.