Key problems of mechanically dithered system of RLG

Mechanical dither is widely applied to reduce lock-in of the ring laser gyroscope(RLG) based on the principle proposed by Sagnac in 1913. This article reviews recent developments in the field for the optimal design of the dither mechanism that decides the effect of bias to some extent. The proper dither signal and its control directly influence dither efficiercy. Stable and accurate error compensation can further the improve the performance of RLG. Some proposals are then made for future research in the field.