导航卫星双频复用信号模拟失真的仿真

导航卫星有效载荷信号生成链路组成部件的非理想特性不可避免会引起发射导航信号的失真，目前对于这种失真带来的信号测距性能损失并未有适用的解析模型。针对宽带双频复用信号的模拟失真，采用相关损耗、S曲线偏差和载波相位偏差作为评估指标，仿真评估了载荷模拟组件中高功率放大器（HPA）、HPA前置滤波器、多路复用器（OMUX）对AltBOC、TD-AltBOC、ACEBOC和AltLOC不同调制方式测距性能的影响。其中对于HPA使用了有记忆HPA行为模型，考虑了不同HPA前置滤波器带宽和HPA工作点的影响，并评估了失真信号相对于理想信号在宽带导频和单边带导频2种跟踪方式下的性能损失。仿真结果可以为信号调制方式比较评估、有效载荷信号生成链路的优化设计提供参考。

Simulation of analog distortion of dual-frequency multiplexing signal generated by navigation satellite

The non-ideal components of the signal generator of a navigation satellite payload can distort the transmitted signal.On the one hand, no applicable analytical model about the ranging performance loss caused by such signal distortions has been established by far.On the other hand,the existing simulation stud-ies about the analog distortions of wide-band dual-frequency multiplexing signals are not quite comprehensive. Taking the correlation loss,S-curve bias,and carrier phase bias as evaluation index,this paper simulates and evaluates the effects of the payload analog components including the high power amplifier(HPA), pre-HPA filter,and output multiplexer(OMUX) on the ranging performance of 4 different dual-frequency multiplexing modulations including AltBOC,TD-AltBOC,ACEBOC and AltLOC.In the simulation,we employ a memory behavioral model of HPA instead of a memoryless model, taking the effects of different pre-HPA filter band-width and HPA operating points into account.In addition,the performance loss of the distorted signal relative to the ideal signal is evaluated for both the double sideband and the single sideband pilot tracking methods. The study provides a useful reference for not only the comparison and evaluation of different signal modulation schemes but also the optimization design of the payload signal generator.