Nowadays, the combined attitude measurement method of inertial sensor and dual antenna RTK ( real time kinematic) is widely used in the field of vehicle attitude measurement. This method integrates the characteristics of rapid update rate of inertial sensor and the advantages of high accuracy of dual antenna RTK. When encountering high buildings or trees, the satellite signal will be lost, resulting in the dual antenna RTK unable to provide the available heading angle, and the inertial sensor cannot maintain the heading angle accuracy for a long time. This paper attempts to adopt an information fusion method based on micro inertial measurement unit miniature inertial measurement unit(MIMU), magnetic sensor and dual antenna RTK. The experimental analysis of the actual sports car is carried out. It is concluded that this method can ensure the stable output of high-precision vehicle attitude data by introducing magnetic sensors to provide heading information under the condition of satellite signal loss.