Abstract: Fiber optic gyro(FOG) strapdown inertial navigation system used in orientation has an advantage of independence, but its system error accumulates with time; Global position system(GPS) can provide more accurate information, but it is interfered easily. FOG and GPS was integrated using information fusion technology. GPS height information was introduced into vertical channel to restrain error increasing basing on setting feedback coefficients. GPS latitude, longitude and horizontal velocity was introduced as Kalman filter observation to remove accumulating error. Information fusion means presented here was applied in a medium-precision FOG/GPS navigation system, and tested in a vehicle. Error of system output positioning parameters was not increased along with time. The testing results are presented to validate the availability and engineering utility of the information fusion means.