论文部分内容阅读
1.引言众所周知,在短波通讯、天波雷达工作频率的预报中,仅以长期预报方法已不能满足现今工程应用的要求,只有采用短期预报或实时预报电离层的传播条件,就需对电离层进行实时监测,才能解决和提高预报工作频率的精确度。高频返回散射探测,可作为实时监测电离层较理想的手段,为短波通讯、天波雷达提供工作频率。为此目的,我们对高频返回散射观测资料(1991年11、12月)进行统计、分析、讨论及其变化规律和特性的研究。 2.高频返回散射仪的工作原理及其主要性能、指标高频返回散射仪的工作原理是:发射机A和接收机B放在同一端工作,当发射机在某个预选的工作频率时,发射的电波斜向入射到电离层,再经电离层把电波反射到地球表面或地物,因地球表面或地物的不平坦和电气不均匀性,对无线电短波产生散射作用,而其中有一部分电波的能量是按原来入射的路径,经电离层再次反射(单次跳越或多次跳越),返回到接收机B端,被接收机收到返回信号,其过程如图1所示。
1. INTRODUCTION It is a well-known fact that only the long-term prediction method can not meet the requirements of current engineering applications in short-wave communications and skywave radar operating frequency prediction. Only when short-term forecasts or real-time prediction of ionospheric propagation conditions are used, Real-time monitoring, in order to solve and improve the accuracy of the forecast frequency of work. High-frequency backscattering detection can be used as an ideal means of real-time monitoring of the ionosphere to provide working frequencies for shortwave communications and sky wave radar. To this end, we conduct statistics, analysis, discussion and research on the laws and characteristics of high frequency backscattered observations (November and December 1991). 2. High-frequency backscatter works and its main performance indicators, high-frequency backscatter indicator works: Transmitter A and receiver B on the same side work, when the transmitter at a preselected operating frequency , The emitted radio wave is obliquely incident on the ionosphere and then the radio waves are reflected by the ionosphere onto the earth’s surface or features. Due to the unevenness and electrical unevenness of the surface or the earth’s surface, radio shortwaves scatter, Part of the radio wave energy is the original incident path, again reflected by the ionosphere (single jump or multiple jumps), returned to the receiver B-side, the receiver receives the return signal, the process shown in Figure 1 .