Interferometric fiber-optic gyro（IFOG） is a new fiber-optic gyro

whose performance decides the precision of the inertial navigation system.The analog signal of IFOG is so weak that it is easily disturbed by many kinds of noises when it is static.So it is hard to evaluate the static performance of IFOG.A project which can measure and filter this weak signal is advised aimed at some IFOG.It is proved that this project can improve S/N of IFOG’s output and effectively pick-up the original signal at real-time from all kinds of noises by a lot of static and dynamic experiments.Meanwhile this project is relatively cheap.