我国的气象卫星及其应用

 在敬爱的周恩来总理“要搞我们自己的气象卫星”方针指引下,中国的气象卫星事业经历了创建、成长和壮大三个阶段。现已建成国家气象卫星资料接收处理中心以及设在北京、广州、乌鲁木齐3个气象卫星地面站的气象卫星应用系统。1988～2000年我国共发射了5颗气象卫星,成为世界上少数拥有极轨、静止两种系列气象卫星的国家之一。其中风云一号C星被世界气象组织正式列入业务应用卫星序列。目前,气象卫星接收网遍布全国,气象卫星应用产品已遍布全国各地,为众多的应用部门所使用。气象卫星气象卫星属遥感类卫星,用多通道高分辨率扫描辐射计、红外分光计和微波辐射计等遥感器俯视地球,一切气象,尽收眼底。     

边缘修正CV模型的卫星遥感云图分割方法

对卫星遥感云图进行自动分割是分析卫星云图资料的重要步骤。为了更加准确的对卫星遥感云图进行分割,提出了融合边缘信息CV模型的卫星遥感云图分割方法。对原卫星云图进行扩散,得到平滑图像,根据平滑图像计算边缘信息,将得到的边缘信息融入CV模型中,并加入距离规范项使得CV模型的水平集函数在演化过程中不需要重新初始化。实验结果表明,与传统CV模型、区域能量拟合水平集模型、偏置场修正水平集模型相比,所提方法分割出的云区域更加准确,分割速度更快。     

基于实测光谱分析的HJ-1B数据浅层雪深反演

积雪的重要性是不言而喻的同时积雪所带来的危害也受到越来越多的重视.目前,积雪深度遥感监测研究主要集中在微波遥感,少量的利用光学遥感进行的积雪深度研究也主要是利用气象卫星数据以及MODIS数据等.我国自主发射的环境与灾害监测小卫星无论是在光谱分辨率还是在空间分辨率上,都与气象卫星数据以及MODIS数据有较大区别,对利用H...     

气象卫星云图压缩编码方法的研究

本文根据对气象卫星云图统计特性的研究结果,提出了一种“差分变换—Huffman编码算法”,并利用该算法对气象卫星云图进行信息保持型压缩编码。文中介绍了在程序中应用本文作者所提出的最小频数顺序合成—逆序分解算法实现这种压缩编码的基本步骤。通过对实际卫星云图磁带数据的压缩编码,结果表明,平均压缩比高达2.4～3.9,最高编码效率达97.9%,并且解码复原图象准确无误。     

数字化卫星云图自动识别的动态聚类算法

根据数字化气象卫星资料的特点，设计了对卫星云图进行自动分类识别的动态聚类算法，利用ＧＭＳ－５的１０．５￣１１．５μｍ和０．５５￣０．９μｍ两个通道的资料，采用迭代自组织的数据分析算法对云图进行了分类试验。     

太赫兹大气遥感技术

由于其独特的大气敏感特性,太赫兹波在大气遥感领域起着越来越重要的作用。国际上太赫兹大气遥感技术发展方兴未艾。2004年,美国NASA发射AURA卫星,探测仪器中包括了具有两种极化的2.5 THz辐射计;2007年,欧空局ESA研制了Marschals外差式光谱仪,采用临边探测方式探测气体成分在亚毫米波段热辐射的高光谱。我国在轨气象卫星风云三号已经具备毫米波段辐射计,风云四号卫星是世界上首颗搭载太赫兹遥感仪的地球静止轨道气象卫星。针对我国大气遥感的现状,在概述国内外太赫兹遥感应用和技术的基础上,提出发展自主知识产权的大气遥感技术的思路;大力发展自主知识产权的太赫兹关键器件、太赫兹探测仪系统集成,研究太赫兹大气探测的新原理和反演新方法,整体提升我国在大气遥感领域的技术水平。     

基于被动遥感卫星可见至红外通道观测的云特性遥感

云是地球辐射收支、水循环和生物化学循环的主要调节者。自1960年人类第一颗气象卫星(TIROS)的发射起,被动卫星遥感已经发展成为获取云观测资料最高效的手段之一。被动卫星具有观测范围大、时间跨度久的特点,其中利用可见至红外波段(0.40～15μm)的遥感成像仪相对高光谱成像仪、微波成像仪具有时空分辨率更高的观测优势。首先,针对极轨卫星多光谱成像仪、多角度偏振成像仪和新一代静止卫星成像仪三类载荷概述了被动卫星基于可见至红外波段的观测特点。然后,介绍了包括云检测、云相态、云顶参数、云光学和微物理参数的观测原理和应用方法。最后,通过总结和展望为被动卫星可见至红外资料的云特性遥感研究提供一些思考。     

遥感卫星图像特征分析

 一、引言遥感是一门新兴技术,它随着空间技术、传感器、计算机与图像处理技术发展而迅速发展起来．在遥感卫星中,按照传感器的成像原理和工作方式,可以分为主动式和被动式两类．被动式传感器接收目标自身的热辐射或反射太阳辐射,如各种相机、扫描仪、辐射计等,这一类传感器又称之为光学传感器．从传感器的发展过程来看,光学传感器成像技术已比较成熟,其中以美国陆地卫星（Ｌａｎｄｓａｔ）和法国ＳＰＯＴ卫星为典型代表;主动式传感器能向目标发射电磁波,然后接收目标反射的回波,主要指各种形式的雷达,特别是星载合成孔径雷达,其中以欧空局ＥＲＳ卫星和加拿大ＲＡＤＳＡＴ卫星为典型代表．     

水汽“吸收再发射模型”的解释与应用

卫星水汽图像的基本原理是卫星云图教学中的难点.通过构建概念模型——“吸收再发射模型”直观地展现水汽吸收再发射过程,加深学生对概念的理解,使其在天气预报业务中更加准确地解译卫星水汽图像.     

多角度偏振遥感相机DPC在轨偏振定标

为了做好卫星数据应用的技术储备,多角度偏振遥感相机DPC航空预研版已经研制成功并完成了航空飞行实验. DPC相机用于获取地气系统反射的偏振、多角度的太阳辐射信息,其地气物理参数反演依赖于定标的精度. 偏振相机的辐射定标包括强度和偏振两个方面. 本文研究偏振遥感相机的偏振参数的在轨定标原理与方法. 基于偏振遥感相机的设计原理,以相机的偏振辐射模型为基础,探索偏振定标的原理和方法. 使用DPC航空遥感实验数据,初步实现了在轨偏振定标并对定标结果进行了分析. 为将来我国自主星载偏振遥感数据处理和在轨偏振定标提供 关键词： 偏振定标 遥感 在轨定标 DPC     

Functions of retired GEO communication satellites in improving the PDOP value of CAPS

This paper briefly introduces the maneuverable feature of the slightly inclined geosynchronous orbit (SIGSO) satellites under a new control model degraded from the geosynchronous orbit (GEO) communication satellites which will retire as most of the fuel in these satellites has been consumed. Basing on the transmitting Chinese Area Positioning System (CAPS), the authors, by analyses, indicate that such satellites can make an improvement to CAPS constellation configuration, especially to the PDOP value from simulation. The results show that the use of SIGSO satellites can (1) actualize three-dimensional (3D) navigation and positioning compared with the situation, which, only using GEO satellites, cannot be carried out, and improve navigation and positioning accuracy to some extent; (2) reuse the communication services of these satellites for more years, and GEO communication satellites will be retired at a later time and delay their time to become space debris and reduce their pollution of the space environment, so that valuable space resources are maximally used. As for the use of these satellites in the transmitting positioning system, the authors present some views and suggestions in this work. Supported by the National Basic Research and Development Program of China (Grant No. 2007CB815501) and the Chinese National Programs for High Technology Research and Development (Grant No. 2007AA12z343)     

Methods of rapid orbit forecasting after maneuvers for geostationary satellites

A geostationary (GEO) satellite may serve as a navigation satellite, but there is a problem that maneuvers frequently occur and the forces are difficult to model. Based on the technique of determining satellite orbits by transfer, a predicted orbit with high accuracy may be achieved by the method of statistical orbit determination in case of no maneuver force. The predicted orbit will soon be invalid after the maneuver starts, and it takes a long time to get a valid orbit after the maneuver ends. In order to improve ephemeris usability, the method of rapid orbit forecasting after maneuvers is studied. First, GEO satellite movement is analyzed in case of maneuvers based on the observation from the orbit measurement system by transfer. Then when a GEO satellite is in the free status just after maneuvers, the short arc observation is used to forecast the orbit. It is assumed that the common system bias and biases of each station are constant, which can be obtained from orbit determination with long arc observations. In this way, only 6 orbit elements would be solved by the method of statistical orbit determination, and the ephemeris with high accuracy may be soon obtained. Actual orbit forecasting with short arc observation for SINOSAT-1 satellite shows that, with the tracking network available, the precision of the predicted orbit (RMS of O-C) can reach about 5 m with 15 min arc observation, and about 3 m with 30 min arc observation. Supported by the National High Technology Research and Development Program of China (Grant No. 2006AA12Z322), the National Basic Research Program of China (Grant No. 2007CB815503), and the West Light Program of Chinese Academy of Sciences (Grant No. 2007LH01)     

The principle of the positioning system based on communication satellites

It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper introduces how to establish the system, a positioning system based on communication satellites called Chinese Area Positioning System (CAPS). Instead of the typical navigation satellites, the communication satellites are configured firstly to transfer navigation signals from ground stations, and can be used to obtain service of the positioning, velocity and time, and to achieve the function of navigation and positioning. Some key technique issues should be first solved; they include the accuracy position determination and orbit prediction of the communication satellites, the measuring and calculation of transfer time of the signals, the carrier frequency drift in communication satellite signal transfer, how to improve the geometrical configuration of the constellation in the system, and the integration of navigation & communication. Several innovative methods are developed to make the new system have full functions of navigation and communication. Based on the development of crucial techniques and methods, the CAPS demonstration system has been designed and developed. Four communication satellites in the geosynchronous orbit (GEO) located at 87.5°E, 110.5°E, 134°E, 142°E and barometric altimetry are used in the CAPS system. The GEO satellites located at 134°E and 142°E are decommissioned GEO (DGEO) satellites. C-band is used as the navigation band. Dual frequency at C1=4143.15 MHz and C2=3826.02 MHz as well as dual codes with standard code (CA code and precision code (P code)) are adopted. The ground segment consists of five ground stations; the master station is in Lintong, Xi’an. The ground stations take a lot of responsibilities, including monitor and management of the operation of all system components, determination of the satellite position and prediction of the satellite orbit, accomplishment of the virtual atomic clock measurement, transmission and receiving navigation signals to and from each satellite. In the north, the south, the east, the west and the center of Chinese main land, the function of CAPS demonstration system is checked and measured. In cars and on board the system is also checked and measured. The results are as follow: CA-code, horizontal positioning accuracy, 15–25 m (1 σ), vertical, 1–3 m; P-code, horizontal positioning accuracy, 8–10 m (1 σ), vertical, 1–3 m; velocity accuracy, CA-code, 0.13–0.30 m/s, P-code, 0.15–0.17 m/s; time accuracy, CA-code, 160 ns, P-code, 13 ns; determination accuracy of orbit ≤2 m. About 20 million US $ and two years are spent for the development of demonstration. A complete CAPS system is now being established. Supported by the National Natural Science Foundation of China (Grant No. 10453001), the National Basic Research Program of China (Grant No. 2007CB815500), the National High Technology Research and Development Program of China (Grant No. 2004AA105030), and the Funds of the Chinese Academy of Sciences for Key Topics in Innovation Engineering (Grant No. KGCXI-21)     

高离化类Ne铕离子的双电子伴线结构的理论研究

在对高离化态类Ne铕离子及其临近的类Na、类Mg离子的n=3→2跃迁的波长和强度详细计算的基础上，考虑了等离子体中单个谱线的展宽和谱线之间的重叠，得到了类Ne铕离子n=3→2的共振线及其类Na和类Mg离子双电子伴线的结构，并系统地分析了这些伴线对共振线波长和强度的影响.     

星载激光告警技术

随着激光武器技术的迅速发展，美、俄两国多次进行激光反卫星试验，卫星面临的激光威胁已日趋严重，进行星载激光告警技术研究势在必行。本文针对这项技术进行分析。     

“NextView计划”与光学遥感卫星的发展趋势

美国国家地理空间情报局(NGA)发起的“NextView计划”是在“未来成像体系”(Future Imagery Archtecture,FIA)计划失败的背景下提出的。“NextView计划”由WorldView-1和GeoEye-1两颗商业光学遥感卫星组成。卫星的地面像元分辨力分别为0.5 m和0.41 m,是目前世界商业卫星中分辨力最高的两颗卫星。本文介绍了“NextView计划”项目实施的依据,描述了WorldView-1和GeoEye-1两颗卫星的技术指标、工作模式和特点,并对未来光学遥感卫星的发展趋势做出了预测,认为未来光学遥感卫星将向“更高、更快、更小、更准、更艳”的方向发展。     

低轨道量子卫星通信星上交换算法及仿真

量子卫星通信能够解决量子移动通信在航海、航空领域中对于远距离和大范围的需求,而星上交换是量子卫星通信的关键技术之一.本文以低轨道量子卫星通信星上交换为研究对象,提出了一种新的星上交换算法——终端测距法.利用该算法测得终端到相邻小区中心的距离,并将测得的数据上传给当前服务卫星系统,再由卫星系统通过比较距离大小决定终端是否切换.数学分析和仿真结果表明,该算法可靠性高、操作方便,能够在各卫星之间实现平稳切换.     

一种新型准静态拓扑LEO/MEO卫星光网络设计

设计了一种新型的LEO/MEO全球覆盖双层卫星光网络,该结构具有稳定的MESH型连接关系,不仅满足卫星光通信捕获追踪和瞄准ATP(acquisition tracking and pointing)要求,还能简化星载处理和交换,降低路由开销。推导了同层和异层间星间链路空间位置表达式。数值仿真结果表明该网络相邻卫星间距离、方位角和俯仰角变化范围小,非常适合卫星激光链路,可作为构建未来卫星激光网络的参考。     

Resources scheduling for data relay satellite with microwave and optical hybrid links based on improved niche genetic algorithm

The formation of the Space-based Information System with the technology of high performance optical inter-satellite communication and the realization of global seamless coverage and mobile terminal accessing are the necessary trend of the development of optical and microwave hybrid communication. Considering the resources, missions and restraints of data relay satellite optical and microwave hybrid links system, a model of hybrid links resources scheduling is established and a scheduling algorithm based on an improved niche genetic algorithm is put forwarded. According to the multi-user-satellite, multi-time-window, multi-class-antenna and a number of missions with priority weight, the scheduling schemes are generated randomly to begin with and evaluated with the fitness functions. To obtain an optimal scheduling result, an improved niche genetic algorithm is adopted to optimize the scheduling schemes. The simulation result reveals that a satisfactory result is obtained and the improved niche genetic algorithm has advantages in both efficiency and performance in a scenario including a relay satellite with 2 optical antennas and 1 microwave antenna for user satellites connection, 8 user satellites with 64 missions. The simulation indicates that the model and the optimization algorithm are suitable for multi-user, multi-mission and multi-class-antenna hybrid communication recourses scheduling problem.     

A method of autonomous orbit determination for satellite using star sensor

1 Introduction Autonomous orbit determination of satellite means that orbit determination is solely finished on board, independent of the observation of ground system. Study on autono-mous orbit determination of satellite has been very hot in the field of orbit determination currently internationally due to its significance in application. There are two common ways of autonomous orbit determination internationally. One is autonomous orbit deter-mination based on navigation system, such as on-b…