不同干扰对铱星机载导航设备接收信号的影响

铱星是目前使用较广泛的低轨道卫通系统，其机载收发信机已在多种民航客机上应用。由于铱星系统研发较早，未考虑后加入的机载通信系统的干扰，且机载电子环境日益复杂，铱星用户链路信号受到的威胁越来越大，需对其进行更完备的电磁兼容分析。首次建立了铱星下行链路信号的接收模型，分析了天线隔离度和不同干扰下的信号误信率，并用实测验证仿真结果。实验测试了不同频率和占空比的宽带和窄带干扰对铱星机载设备接收的信号质量的影响，与仿真吻合程度较好。结果表明：相同功率水平下，宽带干扰的影响大于窄带干扰；不同种类的宽带干扰造成的影响差异不大；带内和带外的宽带干扰造成的影响差异不大，但窄带干扰的影响呈先减小后增加的趋势；脉冲干扰的影响程度与占空比呈正相关。

The Influence of Different Interferences on Received Signals of Iridium Airborne Navigation Equipment

Iridium is widely used in low orbit satellite communication system currently, and its airborne transceivers have been using in a variety of civil aviation aircraft. Aimed at the problems that the Iridium satellite system being relatively earlier in design on no consideration of the interference of the newly developed satellite navigation system, and the airborne electronic environment being more and more complex, and the threat to Iridium user link signal being increased, more complete electromagnetic compatibility analysis is needed, a model of receiving Iridium downlink signal is established. The antenna isolation and bit error rate under different interferences are analyzed, and the simulation results are verified by experiments. The effects of wideband and narrowband interference with different frequencies and duty cycles on the quality of downlink signal received by the Iridium airborne equipment are tested, which is in good agreement with the simulation. The results show that under the same power level, the influence of wideband interference is greater than that of narrowband interference. The impact of different types of wideband interference is not much different. The impact of in band and out of band wideband interference is not much different, but the impact of narrowband interference decreases first and then increases. The impact of pulse interference is positively correlated with the duty cycle.