基于时差的同类辐射源信号分选定位方法

多站电子侦察系统中,多个观测站接收到的脉冲信号的时差信息可用于信号分选和定位。但当多个参数相近的同类辐射源信号在时域和频域都混叠在一起时,会得到大量虚假时差信息。该文结合目标位置信息场定位法,提出基于时差的同类辐射源信号分选定位方法。该方法首先利用时差窗先验信息,将主站与副站的脉冲进行时差和参数匹配提取同类辐射源的时差信息,然后对得到的所有时差利用目标位置信息场定位法确定目标数目和位置,最后利用定位结果确定真实时差,剔除虚假时差,完成信号分选和目标精确定位。仿真实验验证了该方法的有效性和实用性。     

短基线时差定位技术研究

由于当前的长基线时差定位系统不能对窄波束辐射源目标定位,提出了短基线时差定位技术。首先推导了短基线时差定位算法;然后分别对长、短基线时差定位系统的定位精度分布进行了仿真,根据定位精度需求对时差测量精度提出了要求,通过仿真分析得出两路信号相关算法已经不能满足该时差精度需求,需要研究新的时差测量算法;最后提出了利用信号载频相位信息求时差的研究思路,为高精度时差测量精度的研究提供了参考,也为短基线时差定位系统的实现提供了技术基础。     

一种单星无源高精度定位方法

针对基于双星或多星的卫星通信终端定位系统使用约束多、定位误差大等问题,提出一种单星无源高精度定位方法。利用一个高增益窄波束天线接收辐射源旁瓣泄露信号,同时接收主瓣经卫星转发的信号,通过互模糊函数实现微弱旁瓣信号检测和时差参数估计,结合旁瓣接收天线波束指向信息,实现对目标的准确定位。仿真结果表明,可实现对微弱旁瓣信号的检测和运动目标的高精度定位。     

我国卫星干扰源定位的邻星选择与干扰应对措施研究

卫星干扰定位技术是处理日益增多的卫星通信干扰的重要措施,而利用卫星进行干扰定位离不开邻星的选择。利用主流的双星时差和频差定位技术离不开邻星选择的问题,本文对邻星选择的条件进行了总结和深入分析,提出适用于我国通信卫星系统干扰定位的基于合作卫星的定位方案,梳理出可用的干扰定位资源,并提出了应对卫星通信干扰的其他措施。     

四星时差定位中的卫星构型及其定位性能

针对目前多星联合定位研究中对卫星覆盖区域无法长时间高精度定位的问题,提出了一种新型的四星星座构型,并在STK软件中得到了实现。推导了在地球约束情况下基于四星时差定位的误差模型,对卫星全球飞行过程中星座构型变化时的定位性能进行了仿真。仿真结果表明,新型四星星座可以实现在卫星全球飞行过程中对覆盖区域保持高精度定位,在时差测量误差为50 ns且不考虑卫星位置误差的情况下,定位误差在依45毅波束范围内优于1.5 km,对多星联合定位技术在工程设计应用上具有重要意义。     

带诱饵雷达辐射源目标位置信息场成像定位算法

针对带诱饵雷达辐射源群定位问题,提出了一种基于目标位置信息场的成像定位算法。具体方法为:采用两侦察接收机接收观测区域内目标辐射源信号,直接利用采样数据,通过对侦察机2接收到信号进行傅里叶运算变换到频域,在频域进行时差补偿,然后对时差补偿后信号进行逆傅里叶运算变换到时域,在时域对信号进行多普勒频差补偿,再对时差和频差补偿后信号与侦察机1采样信号进行复共轭求和运算,得到位置信息增量函数,最后采用加权将不同时间片的位置信息增量函数关联起来,从而建立位置信息场。仿真实验表明,本文所提成像定位算法具有较高的定位精度和目标分辨率,为进一步识别重点目标雷达和诱饵雷达提供基础。      

基于时差信息的超视距目标定位与跟踪

本文对超视距目标定位与跟踪问题进行了研究,并给出了一种把主动跟踪技术和无源时差定位技术结合起来对超视距目标进行侦测的新方法.该方法的定位系统由地面站和空中站组成,地面站上的无源侦收设备测得经空中站转发(或反射)的目标信号到达时间差,同时地面站上的主动雷达对空中站进行精密定位,计算出目标信号在这段距离上的传播时间,进而可获得目标信号到达空中站的时间差,此时就相当于在空中站的位置对目标进行超视距侦测,利用时差定位技术就可估计目标的位置信息.通过仿真分析可看出,利用本文的方法可对超视距目标进行良好的定位与跟踪.     

时差无源三站精确定位技术研究

论述基于时差的两种无源三站定位原理，重点介绍脉冲时差加干涉仪技术实现三维机动目标辐射源定位的原理，以及系统采用的自动时差配时，时差检测，时差提取等技术，试验说明这一定位系统具有优越性能，还就波束时差定位原理推导了算法公式。     

基于对流层散射传播的超视距时差定位

针对远距离地面目标的平面时差定位误差大的问题,将对流层散射信号的传播路径经过一定的近似之后,提出了一种基于对流层散射传播的超视距时差定位技术。仿真结果表明,与平面内的时差定位相比,目标距离越远,超视距时差定位的优势越明显。     

基于时差序列的多机无源定位算法研究

多站时差序列定位法是一种针对脉冲辐射源的无源定位方法,它是利用短时间内获得的大量时差信息进行定位。文中基于时差序列的定位体制,提出了2个实用的多机定位算法。在目标脉冲波束扫过我方飞行编队的短时间内,将载机位置近似为常值,从而可以使用能够瞬时定位的两步加权最小二乘算法,当测量误差比较大时,采用最大似然法进一步提高定位精度。仿真结果表明,文中提出的基于时差序列的多机定位算法能够达到较高的定位精度,具有很好的工程实用价值。     

卫星互联网下的VSAT卫星通信

本文介绍了VSAT通信在卫星互联网下的新发展,分析了VSAT系统的互联网接入方式,研究了卫星互联网的技术热点,展望了卫星互联网的发展前景.     

新型数字卫星接收机的寻星功能

分析近几年来推出的新型数字卫星接收机的寻星功能包括寻星指示和接收参数扫描两大功能，以及这些功能特点在寻星操作中的运用。     

GEO卫星受IGSO卫星干扰情况分析研究

文章以倾斜地球同步轨道卫星(IGSO)地球站干扰对地静止轨道卫星(GEO)为研究对象,分析了IGSO卫星运行轨迹以及干扰信号出现的原理,最终得出规避干扰出现的建议或者措施,为卫星操作者提供技术参考。     

Satellite Direct-to-Home

An overview of satellite direct-to-home (DTH) digital television in the Americas is presented, including history, service applications, and a reference architecture identifying key system building blocks. Satellite DTH's relationship to and differences from terrestrial ATSC are highlighted. The paper concludes with notes on the technology evolutions that allowed the introduction of digital DTH satellite service and contribute to its continued growth today.     

Satellite antennas

Communication satellites have evolved from a radio relay in space to encompass other applications such as processing and meteorology. The demand for high capacity communication satellites has led in the past two decades to the development of multibeam antennas, a landmark in satellite antenna technology. Satellite antennas are classified into three categories according to function: communication; tracking, telemetry, and command (TT and C); and special satellite antennas. While the application of shaped beam antennas has been developed to its fullest extent as in INTELSAT VI and VII, an active monolithic microwave integrated circuit (MMIC) phased array will play an important role in future satellite antenna technology. Examples of each state-of-the-art satellite antenna technology and the process of space qualification are presented briefly     

Satellite Geodynamics

Satellite geodynamics concerns the use of space technology in the study of the dynamic processes and movements of the solid Earth. The study involves measurements of the Earth's gravity and magnetic fields, the distortions and relative motions of its tectonic plates and the orientation of, and rate of rotation about, its axis. These studies address fundamental questions of geophysics such as the causes of Earth movements and earthquakes, the nature of convection in the mantle, and the origin of the magnetic field. The use of space technology has helped advance our concepts and models in solid-Earth geophysics. Shortly after the dawn of the space age, tracking data were used to precisely define the pear-shaped Earth. Since that time, other data have given several up-to-date representations of the secularly changing magnetic field and global models of the gravity field. Using this technology, it is now possible to determine the contemporary rate of relative plate motion at the level of about 1 cm a year. There are exciting prospects for future missions in satellite geodynamics. The Geopotential Research Mission is designed to improve gravity and magnetic field models and new, highly portable geodetic systems based on the Global Positioning System and spaceborne laser systems should permit rapid determination of positions with 1-cm precision.     

卫星因特网

卫星通信一直在与地面通信齐头并进地发展,因特网和多媒体通信构成了因特网新的发展动力。因特网商用化和媒体化后遇到了骨干阻塞、接入困难、内容分发慢、不能实时传输等诸多难题,而基于数字图像广播（DVB）的、具有远程接入和内容投送／广播功能的卫星因特网成为解决这些难题的有效途径。基于地面因特网的内容获取（pull)和卫星因特网的内容推送（push)的结合,将成为未来因特网的典型运行形式。     

Satellite communications

This paper provides an introduction to the classic paper “Transoceanic Communication by Means of Satellites,” which was written by J.R. Pierce and R. Kompfner and appeared in the March 1959 issue of the Proceedings of the IRE. This paper also provides a periscopic view of satellite communications development since then. Surprisingly, in some aspect, the fundamental ideas have not changed much after 40 years. Conceptually, most technical development falls within these ideas. Practically, however, technological advances and significant progress has been made in all areas of space segment, ground segment, and launch vehicles. Today, due to its impact and usefulness, satellite communications is no longer the domain of the technologists alone. Instead, it has created industries, established relevant institutions, coordinated regulations and standards, provided employment, and financially benefitted many persons. This paper addresses these issues, which have been indirectly created by the scientists and engineers who developed satellite communications     

Satellite Beam Optimization for the Broadcasting Satellite Service

In view of the forthcoming ITU Regional Administrative Radio Conference for the planning of the Broadcasting Satellite Service at 12 GHz for the American Continent to be held in 1983, there is a need for a means to transfer the service quality requirements for a Broadcasting Satellite Service into a consistent set of satellite and receiving terminal parameters.