Sensing principle of fiber optic gyroscope and quartz flexibility(Q flex) accelerometer is analyzed theoretically.Error model which is made up of the scale factor nonlinearity model,bias model,cross coupling error model and temperature model of IMU in the integrated navigation system is established.The error of the IMU is compensated and digital filter for the signal of IMU sensors is schemed in order to improve the applicability of the integrated navigation system in vehicle.GPS,barometer and rotary encoder are used in the integrated navigation system for resolving the problem of non convergence caused by the long term navigation.The integrated navigation arithmetic using unscented kalman filter is schemed in order to solve the problem of nonlinearity errors in navigation system.The result of simulation and dynamic test of UKF in execrable road is exciting.The above mentioned methods enhance the overall navigation performance.