研究了捷联导引头引起的隔离度问题，建立了捷联导引头延时造成的寄生回路模型，分析了捷联导引头延时引起隔离的机理，得到了捷联导引头延时引起的隔离度函数。研究了导引头延时造成寄生回路的稳定性，在制导参数取不同值情况下，绘制捷联导引头延时引起的寄生回路稳定区域。仿真结果表明：制导系统延迟环节动力学时间常数相对于弹体动力学时间常数越大，对系统克服导引头延时的影响越有利。减小弹体气动力时间常数，可以增强系统容忍导引头延时时间的能力。研究成果对于实现捷联导引头的工程应用具有重大意义。

The disturbance rejection rate problem caused by strap-down seeker was studied, the parasitical loop model induced by strap-down seeker time delay was established, the principium of how time delay causes disturbance rejection was analyzed, and the function of disturbance rejection rate induced by strap-down seeker time delay was deduced. Moreover, stability of the parasitical loop caused by time delay was investigated and of the parasitical loop with different guidance parameters was illustrated. The simulation result shows that, if the guidance system lag increases relatively to the missile aerodynamic time constant, the system can overcome larger seeker time delay; if the missile aerodynamic time constant is reduced, the guidance can tolerate larger seeker time delay. Disturbance rejection rate problem discussed in the paper is significant in the practical utilization.