理论分析了机械抖动激光陀螺(MDRLG)闭锁误差产生的原因，给出了闭锁误差与输入角速率、机械抖动频率和机械抖动幅度的关系。针对激光陀螺读出电路整脉冲计数解调的缺陷，提出了用抛物线方程描述激光陀螺输出信号零速率点的相位特征来补偿丢失的小角速率信息，并且利用激光陀螺零速率点相位的正弦值和余弦值以及零速率点相位的二阶导数进行闭锁误差补偿的新方法。仿真实验结果表明，在整周期采样过程中，激光陀螺最大输出误差由原来的6.25%减小到0.622%，有效地减小了闭锁误差，提高了激光陀螺的检测精度。同时该方法也使激光陀螺输出信号具有良好的稳定性和重复性。

The origin of lock-in error of the mechanically dithered ring laser gyroscopes (MDRLG) is theoretically analyzed. It is obtained that the lock-in error relates to the input angular velocity, the dither frequency and the dither magnitude. According to the limitation of pulse count decoder caused by the readout circuit, a new method for eliminating the lock-in error of RLG is presented. At first, the phase character at the zero rate of crossing is described by a parabola equation. Secondly, the fractional angular signal that is smaller than a pulse count is compensated. Finally, by utilizing the values of sine, cosine and the second derivate of the phase at the zero rate of crossing, the lock-in error is eliminating. The simulation results show that the maximum output error of RLG is reduced from 6.25% to 0.622%. So this method improves the detection precision of RLG, and the output signal of RLG has preferably stability and repetition.