摘要
指出了电离层的结构对电波传播过程的影响 :使标准电波产生DOPPLER频移 ;并给出了标准电波的频移Δf与标准电波的频率 f之间的定性关系 :(1)当电离层的层状结构随高度变化很小时 :Δf∝f ,这时的频移主要是由反射高度的变化引起的 ;(2 )当折射指数 μ变化很小 ,并且忽略电子碰撞和地磁影响时 ,Δf∝ 1/f ,这时的频移主要是由群路径上 μ的变化 (即大气浓度的变化 )引起的。标准电波的频移主要是由两个方面的因素引起的 :从积分路径上看 ,频移与群路径本身的变化有关 ,即与反射高度的变化有关 ;从积分变量上看 ,频移与路径上折射率指数的变化有关 ,而折射率指数的变化主要体现在电离层中电子浓度的变化。正因为电波的频移与电离层之间的关系如此密切 ,对电波频移的探测就显得尤为重要 。
In this paper, we not only point out the effect of ionosphere structure to transmission of radio waves:bringing Doppler frequency shift to standard radio waves,but also give certain relation between Δf frequency shift of standard radio waves and f frequency of standard radio waves:(1) Δf∝f when the variation of the stratified structure of ionosphere with height is very small. The frequency shift is mainly caused by the variation of reflection height;(2) Δf∝1/f when the variation of refraction indexμis very small and the effect of electron collision and earth's magnetic field is neglected. The frequency shift is mainly caused by the variation ofμon the group path (the variation of atmosphere density). The frequency shift caused by two factors mainly. In the integration path, it is related to the variation of group path itself. In the integration variable, it is related to the variation of refraction index that embody in the variation of electron density in ionosphere. It is because of the relation between frequency shift and ionosphere that the observating the frequency shift is very important. It can obtain many abnormal events in ionosphere.
出处
《大连海事大学学报》
CAS
CSCD
北大核心
2002年第B08期126-126,共1页
Journal of Dalian Maritime University
