机载GNSS海洋反射信号的建模与仿真

由于全球导航卫星系统反射(GNSS-R)机载试验耗费大和重复性差,需研制GNSS-R信号模拟器,但没有相应的反射信号模型。提出了一种基于数据拟合的机载GNSS海洋反射信号建模方法。首先,对复杂的GNSS海面反射信号进行近似简化。然后利用ZV模型生成的时延相关功率曲线,通过最小二乘拟合和非线性拟合,建立了多条等时延间隔的海洋反射信号功率衰减模型,从而得到机载GNSS海洋反射信号的时延、功率、多普勒频率参数。最后,对多条反射信号的合路信号进行相关的仿真验证。验证的结果表明模拟的14条反射信号的相关功率曲线与ZV模型理论曲线的相关系数优于0.99,能够有效地用于GNSS海洋反射信号的生成。该方法可根据海面风场、浪高、波高等海面信息,模拟不同海况的海洋反射信号,为GNSS-R信号模拟器的研制奠定基础。

Modeling and simulation of airborne GNSS ocean reflection signal

Due to the large consumption and poor repeatability of global navigation satellite system-reflection (GNSS-R) airborne experiment,it is needed to develop GNSS-R signal simulator.But there is no corresponding signal model.In this paper,a modeling method for airborne GNSS ocean reflection signal,based on data fitting,is proposed.First,the complex GNSS sea surface reflection signal was simplified.Then,the time delay correlation power curve generated by the ZV model was used.The power attenuation model of the ocean reflection signal is established by the nonlinear iterative fitting and the least square fitting.With the method,the time delay,power and Doppler frequency parameters of the airborne GNSS ocean reflection signal could be obtained.Finally,the simulation verification of the multiple combined signals was conducted.The simulation results indicate that the correlation coefficient of the 14 signal correlation power curve and the theoretical curve of the ZV model is better than 0.99,which can be used to generate the GNSS ocean reflection signal effectively.The method simulates the different ocean reflected signals according to the sea surface information such as the sea surface wind field,wave height and wave height,which may lay the foundation for the development of GNSS-R signal simulator.