高频雷达海洋表面电磁散射及海态遥感研究

发布时间：2018-04-30 22:31

本文选题：高频地波雷达 + 电磁散射　；参考：《武汉大学》2014年博士论文

【摘要】：随着海洋在国家战略中占据着越来越重要的地位,在经济建设与国防建设的发展中,对于近岸海洋动力学环境的研究需求越来越紧迫。由于实时有效地对近岸海洋动力学环境进行监测,可以为近岸海洋的生态环境提供科学的依据,并能避免由于不良的海洋动力学环境而带来的对海岸经济的重大损失,因此我们迫切地需要对近岸海洋遥感技术进行更加深入有效的研究。高频地波雷达是超视距雷达的一种,由于其成本相对低廉且使用方便,是近几十年发展起来的一种用于海洋环境监测的新型装备,可对海洋环境进行实时、全天候和超视距的大面积监测,其发展前途及研究价值均相当可观。世界上多个国家和地区都在高频地波雷达上进行了一些研究。高频地波雷达的海态参数提取对于实际生产应用有着重大意义,而电磁散射问题作为高频地波雷达的理论基础,是高频地波雷达能够长期发展的坚实基础。随着科学技术的发展,理论模型与实测数据的不一致对更加深入地理解与应用海洋遥感技术存在一定的限制,因此我们需要建立与实测数据相吻合的理论模型,对现有的理论模型进行一些补充与完善。本论文正是基于这样的课题背景,就海洋粗糙表面电磁散射回波模型进行了理论研究工作,并对海洋动力学参数的提取以及过程中的算法处理作了一些研究。本文的主要工作如下： 1、分析了海洋表面电磁散射原理,通过对海洋表面电磁散射模型进行建模,利用微扰法对经典的一阶散射截面方程进行了推导。 2、详细地对高阶布拉格散射的规律及原理进行了观察及分析,并根据海洋表面电磁散射原理,对于高阶布拉格散射模型进行了建模,然后利用微扰法推导了电磁散射截面方程。根据入射场及散射场模型,结合Maxwell方程组,以及边界条件对高阶布拉格散射截面方程进行了推导。对原有的散射模型进行了补充,并对不同的雷达工作频率下的海洋多普勒回波谱进行了仿真和模拟。 3、在单极子／交叉环的方向图公式和直线二元阵的方向图公式的基础上,推导了单极子／交叉环二元阵的方向图公式,并对单极子／交叉环二元阵的实测雷达回波数据进行了波束形成处理,并将雷达的原始回波与单个单极子／交叉环的波束形成结果,以及与对单极子／交叉环二元阵的雷达回波进行波束形成后得到的结果进行了分析比较。 4、利用高频地波雷达OSMAR-S在布拉万台风期间的观测数据,对于特殊天气情况下即台风天气中的高频地波雷达回波谱进行了分析,对台风到达前,台风到达中以及台风离开后海洋的回波距离多普勒谱呈现出不一致性这一问题进行了详细的观察与分析。
[Abstract]:As the ocean plays an increasingly important role in the national strategy, in the development of economic construction and national defense construction, the research on coastal marine dynamic environment is becoming more and more urgent. Because of the real-time and effective monitoring of the coastal marine dynamic environment, it can provide scientific basis for the coastal marine ecological environment and avoid the heavy loss to the coastal economy caused by the poor marine dynamic environment. Therefore, we urgently need to do more in-depth and effective research on coastal ocean remote sensing technology. High frequency ground wave radar is a kind of over-the-horizon radar. Because of its low cost and convenient use, it is a new type of equipment developed in recent decades for marine environment monitoring. The development and research value of all-weather and over-the-horizon monitoring are considerable. Many countries and regions in the world have carried out some research on HF ground wave radar. The extraction of sea parameters of HF ground wave radar is of great significance for practical application. Electromagnetic scattering, as the theoretical basis of HF ground wave radar, is the solid foundation for the long-term development of HF ground wave radar. With the development of science and technology, the inconsistency between the theoretical model and the measured data has some limitations on the deeper understanding and application of marine remote sensing technology, so we need to establish a theoretical model consistent with the measured data. The existing theoretical models are supplemented and perfected. Based on the background of this thesis, a theoretical study on the electromagnetic scattering echo model of ocean rough surface has been carried out, and some researches have been made on the extraction of marine dynamic parameters and the algorithm processing in the process. The main work of this paper is as follows: 1. The principle of ocean surface electromagnetic scattering is analyzed, and the classical first-order scattering cross-section equation is derived by using perturbation method. 2. The law and principle of high order Bragg scattering are observed and analyzed in detail. According to the electromagnetic scattering principle of ocean surface, the model of high order Bragg scattering is modeled, and then the equation of electromagnetic scattering cross section is derived by using perturbation method. According to the incident field and scattering field model, combined with Maxwell equations and boundary conditions, the high-order Bragg scattering cross-section equation is derived. The original scattering model is supplemented, and the ocean Doppler echo spectra under different radar operating frequencies are simulated and simulated. 3. On the basis of the unipole / cross ring pattern formula and the linear binary matrix direction diagram formula, the unipole / cross ring binary matrix pattern formula is derived. The beamforming data of the monopole / cross loop binary array are processed, and the results of the original radar echo and the single monopole / cross loop beamforming are given. The results obtained by beamforming of radar echo of monopole / cross loop binary array are analyzed and compared. 4. Based on the observation data of HF ground wave radar (OSMAR-S) during Typhoon Brawan, the echo spectrum of HF ground wave radar in typhoon weather is analyzed under special weather conditions, and before the arrival of Typhoon, The inconsistency of echo range Doppler spectrum in typhoon arrival and after typhoon departure is observed and analyzed in detail.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN958.93

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