摘要
随着GPS导航系统的现代化、伽利略和北斗导航系统的发展,为了提高频谱利用率,往往需要在一个频点上发射多路导航信号。非恒包络信号通过非线性放大器后,放大器的AM/PM效应会使导航信号的功率谱扩展,伪码相关函数畸变,造成跟踪精度的恶化。因此,多路导航信号的复合要进行恒包络处理,然而有限的带宽会使导航信号的恒包络特性恶化。首先建立导航信号非线性失真的一般模型,分析放大器非线性效应造成的星座图发散、功率损失与伪码跟踪误差;然后以伽利略系统信号为例,通过仿真给出伪码跟踪误差、功率损失与滤波器带宽、放大器功率输出回退之间的定量关系。研究结果对实际工程中导航信号带宽、放大器工作点的选取有重要的参考价值,对我国导航系统下行信号体制的设计有一定的借鉴意义。
With the modernization of GPS navigation system and the development of GALILEO and Compass navigation system,it's necessary to send multi-channel navigation signals in one frequency band in order to improve the spectrum utilization.The amplifier's AM / PM effects would cause the expansion of the power spectrum and code correlation function distortion when the signals have non-constant envelope,which can result in the deterioration of tracking accuracy.Therefore,multiple composite navigation signals need to be processed to have constant envelope,but the limited bandwidth makes the navigation constant envelope signal degrade.This paper first builds a general model of the navigation signal's nonlinear distortion,and then analyzes the constellation divergence,PRN tracking error and the power loss caused by the amplifier's nonlinear effects.Through the simulation,the quantitative relationships between PRN tracking error,power loss and filter bandwidth,the amplifier power output back are obtained.This paper can provide some reference to the selection of navigation signal bandwidth and operating point of the amplifier,also it can provide some useful suggestion to the system design of downlink signal in China.
出处
《遥测遥控》
2011年第3期14-20,共7页
Journal of Telemetry,Tracking and Command
基金
上海市自然科学基金(10ZR1429100)
上海市优秀学科带头人计划基金(08XD14038)
