Abstract. The integrated GPS/INS system has become an indispensable tool for providing precise and continuous position, velocity, and attitude information for many positioning and navigation applications. Therefore, it is important to gain insights into the characteristics of the integrated GPS/INS system performance, particularly their relationships with key operational factors, such as the trajectory and dynamics. Such knowledge can be used to improve the quality of positioning and navigation results from integrated GPS/INS systems. In order to analyse the influence of vehicle dynamics and trajectory, simulation and field tests have been carried out in this research. The test results show that the vehicle dynamic changes significantly affect the Kalman filter initialisation time and estimation performance depending on the system operational environments.