星载光纤陀螺的最优调制深度

为了选取合适的调制深度以提高星载光纤陀螺在空间辐射环境下的工作性能，通过对闭环光纤陀螺输出信号的信噪比分析建立了光纤陀螺随机游走系数与调制深度的关系的模型。根据该模型对光纤辐射致衰减、光纤长度、光源光功率对最优调制深度的影响进行了仿真研究。结果表明：光纤辐射致衰减越小、光源光功率越大，则光纤陀螺的最优调制深度越大，且相应的随机游走系数越小。增加光纤长度将降低光纤陀螺的最优调制深度，当光纤衰减较大且光纤较长时，过调制技术可能会使光纤陀螺性能恶化。因此，在星载光纤陀螺的设计过程中应根据实际情况对调制深度进行优化，以保证陀螺获得最优的工作性能。理论分析和仿真结果为星载光纤陀螺最优调制深度的选取提供了依据。

Optimum Modulation Depth in Spacecraft|Borne IFOG

In order to improve the performance of spacecraft|borne interferometric fiber optic gyroscope (IFOG) in the space radiation environment by selecting a reasonable modulation depth, a model for describing the relation of the random walk coefficient (RWC) to the modulation depth is developed by analyzing the SNR of the output signal of close|loop IFOG. Simulation for the influence of radiation|induced attenuation (RIA) in the fiber, fiber length, and output power of optical source on the optimum modulation depth is performed. Results indicate that the optimum modulation depth increases with the increase of optical output power and increases with the decrease of RIA in the fiber. Moreover, the RWC corresponding to the optimum modulation depth decreases with the increase of optical output power and the decrease of RIA in the fiber. However, the optimum modulation depth decreases with the increase of fiber length of sensing coil. Furthermore, the use of overmodulation technique could deteriorate the IFOG performance when the fiber length is long and the RIA in the fiber is large. Consequently, in order to achieve the best performance, the modulation depth for IFOG must be optimized according to the actual condition during the design spacecraft|borne IFOG. Theory analysis and simulation results provide a basis for the choice of optimum modulation depth in space|borne IFOG.