基于电离层加热的人工沿场散射RCS估计

在电离层加热理论研究和试验研究的基础上, 根据F层散射体的特征和不均匀体散射理论, 建立了人工沿场散射(AFAS)中散射体的散射截面积数学模型. 通过与国际上理论结果对比, 证明了模型的适用性. 利用模型估算了中国人工沿场散射通信中, 通信频段在20~100 MHz时散射体的散射截面积, 结果显示, 甚高频率(VHF)的低端可达80 dB•m2. 另外, 通过计算验证了雷达波束垂直地磁场方向时可获得最大散射截面积的理论. 

Estimating of RCS of AFAS Based on Ionospheric Heating

In the experimental researches of ionospheric heating, an interesting phenomenon was found: irregularities were excited in the heating experiment, which could scatter radio waves in a special way. The scattering is highly sensitive to the direction of geomagnetic field, and it is termed as AFAS (Artificial Field Aligned Scattering). A number of experimental researches were carried out by using the Platteville high power heating facility and other communication equipments. From these researches, people found that the RCS (Radar Cross Section) of AFAS is quite great, which may be as large as 80dB•m2. This is very useful for scattering communication. To study the application of the AFAS in communication, the estimation of RCS is important. A mathematical model was developed, which is based on the theoretical and experimental researches of the ionospheric heating, the characteristics of the scattering on F region and the scattering theory of irregularities. Comparison of the results between model and theory show that the model is applicable. Using the model, the RCS of AFAS in the frequency range of 20 MHz and 100 MHz were calculated, and a RCS of 80dB•m2 was obtained at low-level of VHF. Our calculation supports that the maximum of RCS occurs when the radar beams are in the direction perpendicular to the magnetic field.