【摘要】 利用Es层对VHF电波的反射或散射作用,可以实现单跳达2 000 km的无线超视距通信。分析了在距离为1 250 km和1 495 km的2条链路试验中统计得到的Es层信道传输特性;在此基础上,对Es层超视距通信调制解调器的组成、工作原理及抗衰落、抗多径时延展宽以及速率自适应关键技术方案进行了简要介绍;并在实验室内搭建了Es层信道模型,在此信道仿真平台上测试了调制解调器的误码性能,得出了实测误码性能曲线与带内三重频率分集PSK相干检测理论曲线相差小于2 dB的测试结论。更多还原

【Abstract】 Sporadic E has a reflection or troposcatter effect on the VHF electric wave,by which a type of wireless BLOS communication may be implemented,with single-hop up to 2 000 kilometres.An analysis about the channel transmission characteristics of Sporadic E derived from the test statistics of two links is first made.The distances of the two links are 1 250 kilometres and 1 495 kilometres respectively.Then a brief introduction to the composition,work principle as well as the anti-fading,anti-multipath delay spread and rate-adaptive technology solution of the Sporadic E BLOS communication modem is offered.Furthermore,a channel model of Sporadic E is made,then bit-error-rate performance of the modem is tested on this channel simulation platform in lab,and a result is achieved that the difference is less than 2 dB between the practical test performance and the ideal performance of triad diversity in band with PSK coherent detection.更多还原