星载SAR双程信道建模与仿真实现

目前卫星移动通信的信道研究主要集中在星-地单程链路对无线电波传播的影响,而在星载SAR回波信号的无线传播环境中,信号需要经过星-地和地-星的双程传播,2次穿越大气层,且要经过地面目标的反射。因此,有必要针对星载SAR的这个特点,建立星载SAR的信道模型,为回波信号的模拟提供参考。在经典的卫星移动通信信道模型C.Loo模型的基础上,考虑星-地和地-星链路损耗及地面后向散射系数,推导了星载SAR星-地-星双程链路的理论信道模型,并利用正弦和方法设计了与理论模型相对应的仿真模型,通过仿真验证了理论模型和仿真模型的一致性。

Modeling and Simulation Implementation of Spaceborne SAR Round-trip Channel

The present research on satellite mobile communication channel focuses on the effects of satellite-ground one-way link on the radio propagation,but in the environment of spaceborne SAR,the signal needs to travel in the satellite-ground and ground-satellite round-trip link,pass through the atmosphere twice and be reflected by ground targets.So it is necessary to establish a round-trip channel model of spaceborne SAR.In this paper,considering the round-trip path loss and surface backscattering coefficient,we establish a theoretical channel model for spaceborne SAR on the basis of the classic C.Loo model,and design a corresponding simulation model based on sum of sinusoids.Simulation results indicate that the probability density function（PDF）of simulation model is close to that of theoretical model.