A multipath channel model for wideband communication links is presented for study of the low elevation performance of wideband TT&C (Tracking,Telemetry and Command) and communication links for UAV (Unmanned Aircraft Vehicle) systems,a hot subject of research in recent years.Based on this,amplitude attenuation,carrier phase shift and data chip delay of the reflected path and their effect on data reception are studied.A simulation model is constructed to analyze variation of the amplitude of received signals at different ranges,flight heights and operational frequencies.The results are in essential agreement with the results of field tests.Therefore,the proposed model is of high significance for application in field flight tests.Finally,design suggestions are given from the perspective of engineering systems.%无人机宽带测控通信链路在低仰角下的性能是近年来的研究热点与难点.首先给出低仰角情况下的宽带多径信道模型,在此基础上深入研究了地面反射路径的幅度衰减、载波相位偏移和数据码元时延,及其叠加在直射路径上对数据接收的影响；其次建立了仿真模型,分析在不同作用距离、飞行高度以及工作频率情况下接收电平幅度衰减变化趋势,并与外场实测数据进行比对验证,结果表明,给出的宽带多径信道模型基本上能够反映出外场实测数据的变化趋势,在实际飞行任务中具有较强的现实指导意义；最后从实际工程系统角度出发给出了相应的设计建议.
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