C波段蒸发波导传播衰落特征的试验研究

海洋蒸发波导是海上超视距传播的主要机制,对于海上无线电系统的设计和运行具有重要影响.利用在我国南海开展的蒸发波导环境下的C波段微波超视距传播试验数据,对比分析了不同传播距离下的路径损耗和信号快衰落分布特征.试验结果表明:随着传播距离的增大,路径损耗逐渐接近对流层散射传播损耗,主要传播机制也逐渐从蒸发波导传播向对流层散射传播过渡;5min采样的接收信号电平快衰落分布接近为广义瑞利分布,衰落深度和衰落幅度均小于瑞利分布.所得结果对利用蒸发波导的通信系统设计具有参考价值.

Experimental study on fading characteristics in the evaporation duct propagation at C band

The evaporation duct is an important anomalous transhorizon propagation mechanism in marine areas. It has important effects on the design and operation of marine radio system. Based on the experimental data of C-band microwave transhorizon propagation in evaporation duct environment in the South China Sea, the characteristics of path loss and fast signal fading distribution at different propagation distances are compared and analyzed. The experimental results show that with the increase of propagation distance, the propagation loss gradually approaches the tropospheric scattering propagation loss, and the main propagation mechanism gradually transits from evaporation duct to tropospheric scattering. The fast fading distribution of the received signal level sampled in 5 minutes is close to the generalized Rayleigh distribution, and the fading depth and amplitude are smaller than the Rayleigh distribution. The results are valuable for the design of over-the-horizon communication system using evaporation duct.