Lower atmospheric duct monitoring based on ground-based GNSS occultation signal
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摘要: 大气波导对超短波及以上频段无线电波传播影响显著,为解决海上大气波导参数实时获取问题,提出从地基接收全球卫星导航系统(GNSS)掩星过程的接收信号中提取海上低空大气波导环境信息. 采用抛物方程方法实现由大气波导参数预测地基GNSS掩星信号接收功率的正演模型. 通过遗传算法结合正演模型、参数化的大气波导模型和目标函数,实现根据GNSS掩星信号接收功率得到大气波导参数的反演算法. 仿真模拟了标准折射、表面波导和悬空波导环境对近地面接收GNSS掩星信号的影响. 通过试验获得不同折射环境下北斗卫星导航系统(BDS)、GLONASS、GPS实测掩星信号,并利用实测GNSS掩星信号进行了低空大气波导的反演. 结果表明:所采用的方法能够有效的监测反演海上低空大气波导,且具有无源被动遥感的特点.Abstract: The atmospheric duct has a significant impact on the propagation of ultra-short and the above radio waves. In order to solve the problem of real-time acquisition of the parameters of the marine atmospheric duct, it is proposed to extract the environmental information of the marine atmospheric duct from the received signals of the ground-based GNSS satellite occultation process. The parabolic equation method is used to realize the forward model for predicting the received power of ground-based GNSS occultation signals from ducting parameters. Through combining the forward model, the parameterized atmospheric duct model and the objective function with genetic algorithm, the inversion algorithm of ducting parameters based on the received power of GNSS occultation signal is realized. The influence of standard refraction, surface duct and elevated duct on GNSS occultation signal received near the ground is simulated. Through experiments, the measured occultation signals of Beidou, GLONASS and GPS under different refraction environments are obtained, and the measured GNSS occultation signals are used to retrieve the low-altitude atmospheric duct. The results show that the adopted method can effectively monitor and retrieve the low-altitude atmospheric duct, which has the characteristics of passive remote sensing.
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Key words:
- atmospheric duct /
- path loss /
- parabolic equation /
- genetic algorithm /
- occultation
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表 1 低空大气波导反演参数
波导参数 单位 搜索边界 反演结果 最小值 最大值 c1 M 单位/m −1 0.4 0.066 zthick m 0 500 434.6 zb m 0 1500 101.8 Md M 单位 0 50 29.3 -
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