The resonance was emerged during the outdoor vehicle experiment of the fiber optic gyro position and azimuth determining system, thus brought about relatively great errors. The system structure has been optimized,improved and a reasonable vibration dampening design has been employed in this work. The simulation results and the outdoor vehicle experiment show that the system accuracy has〖HJ*4/9〗 been improved and satisfied the overall requirements. The improved system can be used to other vehicles and the fire control system.