卫星导航信号抗单频干扰性能研究

摘要

For different signal structures,the degradation of tracking performance caused by CWI (continuous wave interference) is different. The traditional analyses and the corresponding results are obtained with the assumption that the CWI complies with the Gaussian distribution and the effect of PRN (Pseudo-Random Noise) on performance is ignored. With the consideration of the effect of discrete spectrum line of PRN code, the expression of the maximum code tracking error of the non-coherent early-minus-late power discriminator for infinite front-end bandwidth case under CWI is provided and the validation of the expression by computer simulation is performed. The maximum tracking error, average tracking error, and relative tracking error are used to evaluate the anti CWI performance of the GNSS (global navigation satellite system) signal. The comparison of the tracking performance between the coherent early-minus-late and the non-coherent early-minus-late power discriminators under CWI shows that their performance difference is obvious under low signal-to-interference ratio and the performance difference depends on the modulation types. At last,the evaluation of the anti CWI performance among all GPS C/A codes and the comparison of the performance among BPSK(1) ,BOC(1,1),and MBOC(6,1,1/11) under CWI are performed, respectively.%不同信号体制的导航信号受单频干扰的影响不同.目前针对此问题的分析都是在干扰为高斯分布以及忽略伪码离散频谱的前提下进行的.本文针对非相干超前减滞后功率鉴相器,考虑了伪码离散谱线的影响,导出了非带限情况下单频干扰导致的最大跟踪误差的解析式,并进行了仿真验证.提出用最大跟踪误差,以及在此基础上得出的平均跟踪误差和相对跟踪误差来评价不同信号体制的导航信号在单频干扰下的性能.通过和相干超前减滞后鉴相器在单频干扰下的性能对比,结果表明仅在低信干条件比下,二者的性能差异才明显,且不同调制方式性能差异的位置不同.仿真分析了BPSK(1),BOC(1,1)和MBOC(6,1,1/11)信号在单频干扰下的跟踪性能和所有GPS C/A码的抗单频干扰性能.