北斗卫星导航空间信号模拟畸变研究

针对卫星导航信号生成载荷故障会导致信号畸变，对北斗卫星导航信号模拟进行了研究分析。首先，建立了北斗导航信号模拟畸变的数学模型并对其进行了理论分析；其次，推导了北斗信号发生模拟畸变后的相关函数、功率谱密度函数和相关损耗，并仿真分析了北斗信号模拟畸变的相关峰曲线、功率谱密度曲线和相关损耗曲线；最后，利用S曲线及S曲线锁定点偏差的模型，仿真了北斗模拟畸变信号S曲线及S曲线锁定点偏差，并分析了北斗信号发生模拟畸变对测距性能产生的影响。结果表明：北斗信号发生模拟畸变的畸变程度越大，伪距测量误差越大，则导航系统的测距精度和定位精度越低，增强系统的完好性越小。

Research on Analog Distortion of Signal in Space for Beidou Satellite Navigation System

The failure for signal generated payload of satellite navigation will cause signal distortion. When signal of satellite navigation is distortional, the performance of navigation will be influenced. Therefore, the threat model for analog distortional signal of Beidou is researched and analyzed. The mathematical model for threat model B of Beidou is established and is analyzed theoretically. The formulas of cross-correlation function, power spectrum density and correlation loss are derived, and they are simulated and analyzed. In accordance with the mathematical model for S curve and S curve locking point bias of threat model B, S-curve and S-curve locking point bias are simulated and the impact on measurement performance is analyzed. The results demonstrate that the anomaly signal for Beidou will cause pseudorange measurement error. Furthermore, with the greater degree of distortion, the accuracies of Beidou including ranging accuracy and positioning accuracy are reduced, so does the integrity for augmentation system.