一种兼容型空基区域导航增强脉冲信号设计

Design of a Compatible Pulse Signal for Aircraft-Based Regional Navigation Augmentation

摘要:

空基区域导航增强系统是一种卫星导航系统的有效辅助与补充手段，其信号设计是影响增强定位精度的重要因素；针对系统对导航卫星辅助增强与独立定位的需求，以北斗系统为应用背景，给出了一种能够与北斗卫星信号兼容的区域增强信号设计建议；根据兼容性需求分析结果，对频点、扩频码与电文格式等进行了选择和设计；针对增强系统中可能存在的远近效应，提出了脉冲调制的优化方式，根据信号参数设计适用于空基区域增强信号的脉冲信号占空比，并设计相适应的脉冲图案；仿真结果表明，采用脉冲信号形式的区域增强信号能够与北斗卫星信号实现兼容，卫星信号比区域增强信号弱30 dB时能够正常捕获，减弱远近效应的影响。

Abstract:

The aircraft-based regional navigation augmentation system serves as a crucial auxiliary and complementary component to satellite navigation systems, with its signal design being a pivotal factor influencing augmentation positioning accuracy. Considering the system's requirements for both navigation satellite augmentation and independent positioning, this study proposes a regional augmentation signal design that is compatible with the BeiDou satellite signal, using the BeiDou system as the practical context. Based on the findings of a compatibility requirement analysis, careful selections and designs were made for carrier frequency, spread spectrum codes, and navigation message formats. Addressing the potential near-far problem issues within the augmentation system, an optimization method for pulse modulation is introduced. The duty cycle of the pulse signal, tailored for space-based regional augmentation, was designed in accordance with the signal parameters, and the corresponding pulse pattern was developed. Simulation results demonstrate that the regional augmentation signal in pulse form is compatible with the BeiDou satellite signal. Furthermore, the satellite signal can be successfully captured even when it is 30 dB weaker than the regional augmentation signal, effectively mitigating the impact of the near-far effect.