A micro displacement measurement method based on PGC demodulation of space optics

An improved interferometric system aiming at measuring micro displacement is put forward on the basis of phase generated carrier(PGC) demodulation of space optics. This system can improve the accuracy of Absolute Gravimeter(AG) by measuring the amplitude and direction of ground vibration. While the carrier frequency is between 1K and 2K, ground vibration with low frequency (10Hz to 100Hz) and micro vibration amplitude (30nm to 300nm) can be obtained, which satisfies the requirements of AG.