【作者】 曹海林；

【导师】 杨士中； 杨力生；

【作者基本信息】 重庆大学 ， 电路与系统， 2010， 博士

【摘要】 深空探测是人类在新世纪的三大航天活动之一。深空测控通信系统完成对深空探测器测控及通信。论文密切结合总装预研项目“S/Ka测控通信系统研究”中关键技术之一“窄波束天线捕获”需求,以实现粗略轨道预报下的窄波束大天线的快速捕获为出发点,对深空测控通信大天线相关技术展开研究。作者的主要工作和创造性成果可概括为以下几个方面:①研究了基于物理光学法的大反射面天线辐射场计算方法,并利用Matlab实现了计算软件包。对几种常用于天线仿真设计的电磁计算方法及相应的商用软件进行了分析,并总结出了适用于本文的天线设计方法。利用Matlab实现了基于物理光学法的大天线辐射场计算软件包。最后将基于Matlab代码的计算结果与通用反射面天线GRASP软件的仿真结果进行比较分析,两种仿真结果相符,表明了本文开发的计算软件包的正确性及可靠性。为本文后续的研究提供了基础。②研究了阵列天线馈电大反射面天线系统的灵敏度、效率、噪声等性能参数,提出了基于电小喇叭阵列馈电改善大反射面天线性能的思路。基于二维阵列的结构分析,对适合用于反射面馈电的六边形阵进行了研究。针对深空测控的应用,分别研究了基于电大喇叭阵列馈电和电小喇叭阵列馈电的大反射面天线性能。仿真和分析结果表明:利用阵列天线对反射面馈电可以改善大反射面天线灵敏度及可视范围;电小喇叭阵列馈电的反射面天线与电大喇叭阵列馈电的反射面大天线相比,具有更广的可视范围及更高的孔径效率。③针对深空测控通信中地面站窄波束天线捕获深空探测器的难题,提出了一种电波束扫描和机械扫描相结合的多波束-螺旋快速扫描捕获方法。从反射面天线偏馈扫描原理出发,利用物理光学法对偏馈反射面方向图进行分析,对共焦面馈源阵列中每个馈源照射反射面形成的次级远场方向图计算,利用间接共轭场匹配技术综合出多个正交的波束,形成了具有更广的可视范围多波束反射面天线,以更大螺距进行螺旋扫描。仿真和分析结果表明:多波束—螺旋扫描在较粗预报范围能快速对指定空域完成扫描、捕获探测器;利用共轭场匹配技术综合的多波束不但能改善天线的可视范围,而且获得了更高的增益,改善了链路中信号的信噪比,为更远的深空探测提供可能。④为了改善深空测控通信中大口径窄波束天线的扫描范围,提出了一种基于粒子群算法(PSO)的阵列馈电波束综合的方法。在深入研究PSO算法特性的基础上,提出了先利用物理光学法计算共焦面馈电阵每个馈源照射反射面的次级远场方向图并进行存储,再用PSO对馈电阵列的权值进行优化,对各个馈源产生的次级方向图加权综合出期望方向图的思想。仿真和分析结果表明:基于PSO优化方法与传统共轭场匹配方法相比,更能精确指向期望方向、控制旁瓣电平、综合出期望方向图、扩大深空测控通信天线的可视范围。⑤研究了深空测控通信中天线组阵技术,提出了一种适用大规模平板阵的快速来波方向(DOA)估计方法。研究了现有深空测控通信系统中大天线及天线组阵的技术与特点,探讨了大规模平板阵在深空探测中的应用。提出了一种利用新颖的平行阵结构、基于传播因子方法的快速DOA估计方法。仿真和分析结果表明:该算法可以实现快速而精确的DOA估计,适用于大规模阵及实时DOA估计。⑥研究了大反射面天线馈源阵列技术,主要设计一种有EBG结构的六边形馈电阵列。首先设计了加扼流槽电小喇叭馈源,仿真和实测结果表明扼流槽结构可使圆锥喇叭主瓣平坦、主瓣边缘变化陡峭,更适用于组阵。在深入研究EBG结构的带隙特性及抑制表面波特性的基础上,设计了一种基于EBG结构的六边形微带天线阵列馈源结构,并对其性能进行了实测和分析。结果表明:EBG结构可以有效抑制天线阵元之间的互耦,改善天线匹配及圆极化特性;基于EBG结构的六边形馈源阵列较无EBG结构性能有较大提高,更适用作反射面天线的焦平面馈电阵。更多还原

【Abstract】 Deep-space exploration is one of the three space activities in the new century. Deep-space telemetry, tracking & command (TT&C) and communication system is to complete the TT&C and communication for Deep-space spacecraft. Related tightly to the pre-research project entitled“S/Ka TT&C and Communication System Research”, this dissertation presents a systematic investigation into the technique of large antennas for deep-space TT&C and communication, which started with capturing spacecraft using narrow beam-width large antenna under a rough orbit forecast in little time. The major contributions of the dissertation on this subject can be summarized as follows:①The software package for calculating the radiation field of large reflector antenna using Matlab is developed, which based on physical optics. After a brief review of several computational electromagnetic methods and the corresponding commercial software commonly used in antenna design, the method of antenna analysis in this dissertation is addressed. The software package based on physical optics for calculating the radiation field of large reflector antenna is developed with Matlab. The accuracy comparison is carried out between our package and commercial software-General Reflector Antenna Software Package (GRASP). These simulation results show the accuracy of our software package is consistent with commercial software. This package provides the basis for follow-up research.②The performance of reflector antenna system using a focal-plane array, such as sensitivity, efficiency and noise, was analyzed. The antenna performance in terms of efficiency, sentivity and field of view, using a focal-plane array in place of a standard single-mode feed, can be greatly improved. Numerical simulations were performed to compare the large reflector antenna performance between the utilization of an electrically small horn array and an electrically large horn array when beam steering. These simulation results show that the reflector antenna using focal-plane array of electrical-small horn has wider field of view and higher aperture efficiency, comparing with electrically large horn array.③A novel multi-beam spiral scanning method of antennas in deep-space TT&C and communication is proposed. Physical optics was used to compute the far pattern of the antenna for excitation of the individual array elements in focal-plane array. Multiple closely overlapping beams were synthesized with indirect conjugate field matching technique. The simulation results show that, combined with spiral scanning method, the multi-beam reflector antenna can accomplish the desired area scanning in less time under raw obit forecast and the array gain in multi-beam reflector antenna can extend the range of deep-space exploration.④Particle swarm optimization (PSO) is used to synthesis the pattern of the parabolic reflector antenna using a focal-plane array in deep-space exploration. Physical optics was used to compute the far pattern of the reflector antenna for excitation of the individual array elements in focal-plane array, and then stored. Various scanning patterns were synthesized for deep-space TT&C and communication with PSO. These simulated results show that the patterns synthesized with PSO have wider scanning ability, more accurate direction, and lower side lobe, comparing with conjugate field match method.⑤After a detail review of large antennas and array technique in deep-space TT&C and communication, a new computationally efficient algorithm based propagator method for two-dimensional (2-D) direction-of-arrival (DOA) estimation is proposed, which uses two parallel uniform linear arrays. The algorithm takes advantage of the special structure of the array which enables 2-D DOA estimation without pair matching. Simulation results show that the proposed algorithm achieves very accurate estimation at lower computational cost. It’s desired in real time and huge planar array DOA application.⑥The array feed technology for large reflector antenna is investigated. A hexagonal feed array of microstrip antenna with EBG is proposed. A horn with choke was designed. Simulated and experimental results show that the choke structure can improve the horn with a flatter main lobe, a steeper edge and a symmetrical pattern. Taking it combining array, mutual coupling can be smaller. After an in-depth study of EBG structure to suppress mutual coupling between antennas, a hexagonal feed array of microstrip antenna with EBG for reflector antenna was designed. A seven elements array was tested. The results show that the EBG structure can suppress the antenna array mutual coupling between elements, as well as improving the matching and circular polarization performance of antenna. The hexagonal array with EBG is competent for the focal-plane of reflector antenna.更多还原