本文選題：電離層加熱 + 射線追蹤�。� 參考：《西安電子科技大學(xué)》2015年碩士論文

【摘要】：隨著科學(xué)技術(shù)的不斷發(fā)展,電離層通信也漸漸的成為了人類生活的一部分,如廣播、電視、無(wú)線通信、全球定位系統(tǒng)(GPS)的定位和導(dǎo)航等人類活動(dòng)與電波在電離層中的傳播息息相關(guān)。近年來(lái),自從人們發(fā)現(xiàn)人工加熱電離層可以明顯干預(yù)電離層中電磁波的傳播特性,該方向的研究就一直備受國(guó)內(nèi)外學(xué)者關(guān)注。本文基于電離層加熱模型與射線追蹤方法,對(duì)加熱電離層中電波的傳播特性展開(kāi)了系統(tǒng)的研究。主要工作如下:1.簡(jiǎn)要的闡述了人工加熱電離層和在加熱電離層中電波傳播的研究背景和意義。探討了電離層加熱在民用及軍事技術(shù)應(yīng)用上的重要性。2.從電離層歐姆加熱理論出發(fā),根據(jù)電子密度變化的連續(xù)性方程、粒子的動(dòng)量方程和能量守恒方程,介紹了電離層加熱的數(shù)值仿真模型。并以國(guó)際電離層參考模型IRI-2012和中性大氣模型MSIS-90為背景,在不同的加熱時(shí)間和不同的加熱功率的條件下,對(duì)電離層加熱進(jìn)行了數(shù)值仿真。從而確定這加熱時(shí)間和加熱功率對(duì)加熱電離層的電子密度、電子溫度擾動(dòng)的影響。3.基于射線追蹤的Haselgrove方程,在已知背景電離層電子密度梯度的條件下,利用龍格庫(kù)塔數(shù)值計(jì)算方法,介紹了在電離層中電波傳播的變步長(zhǎng)射線追蹤模型。根據(jù)該射線追蹤模型,繪制了電波傳播軌跡。并且對(duì)電波在常規(guī)的、含有Es層的,和含有加熱F層的電離層中傳播的射線追蹤進(jìn)行了仿真和分析。研究了Es層和加熱F層的存在對(duì)電磁波在電離層傳播的影響。4.介紹了在電離層中電波可能存在的傳播模式,從理論上對(duì)多徑效應(yīng)進(jìn)行了分析。其次,給出了電波在電離層傳播過(guò)程中的傳輸損耗、吸收損耗和反射損耗的數(shù)學(xué)表達(dá)式并進(jìn)行了理論分析。接下來(lái),分析研究了電離層豎直方向上的運(yùn)動(dòng),不規(guī)則體加熱F層的豎直方向上的運(yùn)動(dòng),電離層內(nèi)電子密度的變化,以及地磁場(chǎng)隨時(shí)間的變化對(duì)多普勒頻移的影響。最后通過(guò)計(jì)算機(jī)仿真研究了不同發(fā)射仰角和不同發(fā)射頻率的電波在電離層中的回波效應(yīng)。5.首先,對(duì)電波在電離層不規(guī)則體加熱F層的散射理論進(jìn)行了介紹,基于該理論,對(duì)電波在電離層不規(guī)則體F層中的散射進(jìn)行了仿真,為定量分析電波在不規(guī)則體散射的雷達(dá)散射截面RCS提供了理論指導(dǎo)。
[Abstract]:With the development of science and technology, ionospheric communication has gradually become a part of human life, such as radio, television, wireless communications, Human activities such as positioning and navigation of global positioning system (GPS) are closely related to the propagation of radio waves in the ionosphere. In recent years, since it has been found that artificial heating of the ionosphere can significantly interfere with the propagation characteristics of electromagnetic waves in the ionosphere, the research in this direction has been concerned by domestic and foreign scholars. Based on the ionospheric heating model and the ray tracing method, the propagation characteristics of the electric waves in the heated ionosphere are studied systematically in this paper. The main work is as follows: 1. The research background and significance of artificial heating ionosphere and electric wave propagation in heated ionosphere are briefly described. The importance of ionospheric heating in civilian and military applications is discussed. Based on the theory of ionospheric ohmic heating the numerical simulation model of ionospheric heating is introduced according to the continuity equation of electron density the momentum equation of particles and the energy conservation equation. Based on the international ionospheric reference model IRI-2012 and the neutral atmospheric model MSIS-90, the ionospheric heating is numerically simulated under different heating time and different heating power. The effects of heating time and heating power on the electron density and electron temperature disturbance of the heating ionosphere are determined. Based on the Haselgrove equation of ray tracing, the variable step size ray tracing model of radio wave propagation in the ionosphere is introduced by using the Runge-Kutta numerical method under the condition of known background electron density gradient. According to the ray tracing model, the track of radio wave propagation is plotted. The ray tracing in conventional, es and heated F ionosphere is simulated and analyzed. The influence of the existence of es layer and heated F layer on the propagation of electromagnetic wave in the ionosphere is studied. The possible propagation modes of radio waves in the ionosphere are introduced, and the multipath effect is analyzed theoretically. Secondly, the mathematical expressions of transmission loss, absorption loss and reflection loss during ionospheric propagation are given and analyzed theoretically. Then, the motion of the ionospheric vertical direction, the vertical motion of the irregularly heated F layer, the variation of the electron density in the ionosphere and the influence of the geomagnetic field with time on the Doppler frequency shift are analyzed. Finally, the echo effect of radio waves with different elevation angles and different emission frequencies in the ionosphere is studied by computer simulation. First of all, the scattering theory of electric wave in F layer heated by irregularly ionospheric body is introduced. Based on this theory, the scattering of radio wave in F layer of irregularly ionospheric body is simulated. It provides theoretical guidance for quantitative analysis of RCS of radio wave scattering in irregular bodies.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN011

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