莫斯科、伊尔库茨克至南极长城站短波衰落特性分析

为了研究过极区的短波长电路的衰落特性，在南极长城站收测莫斯科、依尔库茨克的短波授时台信号，并给出各频率对应的衰落深度、衰落率、衰落平均持续时间等参数的统计特征和衰落幅度分布曲线。结果表明：（１）在莫斯科、依尔库茨克－南极长城站两条电路上，其电离层短波信道是快衰落信道，信号幅度衰落绝大部分服从瑞利分布，分布特性与频率、时间、距离、位置关系不大；（２）莫斯科－南极长城站电路的衰落深度与频率、时间有关，频率低，其衰落深度大。但依尔库茨克－南极长城站电路的衰落深度与频率、时间无关，说明衰落深度与频率、时间的关系还要受距离、位置等因素的影响。（３）频率越高，衰落率也越高，０４：００～０９：００时段内衰落率高于其他时段。

SHORTWAVE FADING CHARACTERS FOR THE CIRCUITS OF MOSCOW AND IRKUTSK TO THE GREAT WALL STATION IN ANTARCTICA

The two transpolar shortwave time signal circuits,Moscow and Irkutsk to the Great Wall Station in Antarctica, are used to study the fading characters for shortwave long circuit.The ionospheric shortwave channels for the two circuits are rapid fading channels,its signal amplitude fading obeys the Rayleigh distribution essentially and this distribution is independent of time,frequency,distance and geographic location.The fading depth is different for the two circuits. For Moscow to the Great Wall Station circuit,the lower the frequency,the larger the fading depth.But for Irkutsk to the Great Wall Station circuit,there is little relationship between the fading depth and frequency.It seems that the relationship between fading depth and frequency is controlled by the factors such as location,distance etc.The higher the frequency, the higher the fading rate for the two circuits.