北斗导航信号电离层闪烁模拟及其影响

电离层闪烁具有突发性、偶发性和区域性,且难以建模准确刻画。针对电离层闪烁影响下的北斗导航信号复现问题,研究了基于应用伽马分布和零均值高斯分布模型的导航信号电离层闪烁序列生成方法,并基于国防科技大学电子科学与工程学院研制的NSS8000型多体制导航信号模拟器给出了北斗导航信号电离层闪烁模拟的硬件架构。在此基础上,通过中频信号采样和软件接收机处理,分析了电离层闪烁对北斗接收机跟踪环路的影响。结果表明:在相位闪烁指数为0,幅度闪烁指数为0.9时,码环鉴相误差可达0.05 chip;而在幅度闪烁指数为0,相位闪烁指数为0.5时,载波环鉴相误差可达15°,处于失锁的临界状态。

Simulating and Analyzing the Imapact of Ionoshperic Scintillation for BeiDou Navigation Signals

Due to its accidental, sudden and regional characteristics, the simulation of GNSS navigation signals under ionospheric scintillation is difficult to implement accurately. The ionospheric scintillation time-series generation method based on Gamma distribution and zero-mean Gaussian distribution is proposed, and with the NSS8000, a multi-system navigation signal simulator developed by our department, the hardware architecture of BeiDou navigation signal simulation under ionospheric scintillation is given. Then on this basis, by intermediate frequency signal sampling and software receiver processing, the impact of ionospheric scintillation on BeiDou receiver tracking loops is analyzed. Finally, the results indicate that the code tracking error can reach 0.05 chips when the phase scintillation index is 0 and amplitude scintillation index is 0.9, while the carrier tracking error is already reach 15 degrees when the amplitude scintillation index is 0 and phase scintillation index is only 0.5, which the carrier tracking loops is almost loss of lock.