静止轨道瞬态点源多目标闪电信号实时探测技术

闪电是具有代表性的瞬态点源多目标,与雷暴等强对流气象现象有着密切的联系,通过对闪电的观测可获取雷暴雨等强对流天气的分布、变化、定位。文中论述了在静止轨道上利用瞬态点源多目标闪电信号和缓变的云层、陆地与海洋等背景噪声之间存在时间、空间和光谱特性上的差异,采用光谱滤波、空间滤波、帧—帧背景去除三种方法的组合来实现瞬态点源多目标闪电信号的增强与探测的方案及其技术实现,进行了理论分析与试验验证。     

影响雷达系统设计的要素

驾驭雷达系统设计的八个基本要素: 1.功能:雷达起什么作用,应提供什么数据?如果与其它雷达或通信系统协同工作,必须具备什么界面? 2.性能:必须提供什么样的空间区域的数据?分辨力、精度和数据率如何?要求它探测并跟踪的目标的特性怎样?预期的目标的空间、时间和速度分布如何?可以接受的平均虚警时间,要求雷达能在什么样的环境(自然或人造环境)下工作?     

红外遥感技术在民用对地观测卫星中的应用现状（上）

利用卫星遥感技术对地球资源、海洋和大气等环境状况进行监测,可以为人类生存环境提供预测信息和安全保障。红外遥感仪器是对地观测卫星的主要探测载荷。随着红外探测器性能和系统集成技术的不断提高,空间红外遥感仪器的探测能力也得到了长足发展。介绍了近五年各国相继发射的各类高性能对地观测卫星,总结了主要红外遥感仪器的应用状况、功能和特性,并对其未来的发展趋势进行了分析。     

红外遥感技术在民用对地观测卫星中的应用现状（下）

利用卫星遥感技术对地球资源、海洋和大气等环境状况进行监测,可以为人类生存环境提供预测信息和安全保障。红外遥感仪器是对地观测卫星的主要探测载荷。随着红外探测器性能和系统集成技术的不断提高,空间红外遥感仪器的探测能力也得到了长足发展。介绍了近五年各国相继发射的各类高性能对地观测卫星,总结了主要红外遥感仪器的应用状况、功能和特性,并对其未来的发展趋势进行了分析。     

大气层外空间目标红外探测性能分析

由于空间环境的特殊性,对空间红外目标进行探测与大气层内红外目标的探测有明显不同.本文从空间目标的红外辐射原理出发,给出了空间目标红外特性的计算模型,并给出了空间目标在3～5 μm和8～12 μm波段红外辐射强度的计算结果;通过对空间目标红外特性的计算分析.提出了几种探测方案,并分别计算了各方案对空间红外目标的探测距离,...     

深圳市闪电定位系统介绍及其数据应用

介绍了深圳市闪电定位系统的结构、探测原理、探测参量与指标,对数据存储结构及基础数据进行了说明。利用数据库查询功能从时间范围和空间范围内筛选出深圳市闪电定位的数据,采用ArcGis软件的Arcmap组件中的点密度分析功能对其进行分析,得出了深圳市的历年平均地闪密度分布图及雷灾点附近地闪定位图,并统计得出某一位置附近雷电流雷击概率,对雷电灾害风险评估、雷灾调查等领域的应用具有重要意义,如：合理选取地闪密度值、判断灾害是否由雷电引起以及可能引起雷灾的闪电位置及参数等。     

弹道中段目标动态红外辐射特性仿真计算

利用红外光谱辐射特性进行弹道式空间目标探测和识别是一种有效的方法,用该技术探测弹道式空间目标就要对空间目标的红外辐射特性进行研究.在原有目标和诱饵红外辐射特性模型的基础上,综合考虑目标弹道和姿态运动,空间热环境辐射和内热源传热等因素,利用节点网络法建立了弹道中段目标的动态红外辐射计算模型,实现了在不同时刻、不同观测点、不同运动状态下的中段目标红外辐射特性的仿真计算.根据公开的相关资料,设计了两种目标和诱饵,通过对比分析不同弹道条件下目标与诱饵的辐射特性,验证了计算模型的正确性.     

临近空间对地探测目标与背景红外特性研究

红外辐射特性是红外探测系统进行目标识别的主要依据。基于辐射传输原理,面向临近空间对地探测目标与背景的红外特性进行研究。利用全球大气廓线反映全球大气状况先验知识,设计了一套临近空间对地探测红外特性研究的辐射传输仿真方案。利用MODTRAN模型进行仿真,量化临近空间对地探测目标与背景的红外特性差异,分析传感器最优透过率波段以及红外辐射特性的影响因素。结果表明,大气透过率以及目标与背景的红外辐射差异随着临近空间传感器高度的增加而减小,且与大气状况密切相关;得出了传感器在3~14 μm范围内的最优透过率波段;季节、大气能见度与传感器观测角度对目标与背景的亮温差异造成的影响不可忽略。     

凝视型地球辐射探测仪的辐射标定技术研究

凝视型地球辐射探测仪是我国的新型空间应用遥感仪器,仪器具有全波探测通道和短波探测通道,采用腔体探测器,对地凝视观测,视场覆盖地表边缘,用于从空间的低轨道卫星平台测量地球辐射出射总量,提供地球辐射收支信息.作为定量化应用的遥感仪器,对仪器提出了高精度的定标需求,本文结合仪器的设计特点,提出了使用辐射标准传递方法,先用黑体标定凝视型地球辐射探测仪全波腔体探测通道,继而用全波通道标定积分球,再用标定好的积分球对凝视型地球辐射探测仪短波探测通道进行标定的办法,提高了短波探测通道的辐射标定精度.     

地球同步轨道星载降雨测量雷达设计

分析了雨的空间分布特性,对现阶段降雨测量雷达的现状进行了调研,提出了一种地球同步轨道星载降雨测量雷达设计方法。该雷达采用Ka频段工作频率,采用螺旋扫描实现5 000km直径的圆区域覆盖,可实现0.3mm/h以上强度降雨的探测。同时,地球同步轨道降雨测量雷达可实现定点观测,通过3~4颗卫星组网即可实现全球覆盖。该雷达是实现全球气候与环境变化监测,军事战场作战环境综合探测的必要装备。     

Onboard switching for ATM via satellite

This article presents an architecture for onboard ATM switching. The constraints of the space environment and the associated delays (especially with geostationary satellites) create often conflicting requirements for the implementation of ATM via satellite. These requirements must be considered when designing onboard equipment. The article suggests that the use of MF-TDMA framing and of physical-layer scheduling as a preswitching stage allows for the use of standard switch fabrics onboard with additional fault tolerance and buffer mechanisms. The details of the scheduler and of the RF front end, including demodulation and demultiplexing, are presented as well as suitable switch fabrics and their performance/implementation impact. ATM is now widely considered the delivery medium for the broadband services of the future. This fact has also attracted the attention of the satellite community. Current satellite ATM trials have concentrated on trunking applications using available broadcast satellites. However, the US FCC filings for Ka band satellites, as well as Canadian W and European initiatives, have focused on a new generation of digital regenerative multibeam onboard processing satellites     

星载大气痕量气体差分吸收光谱仪定标机构设计

星载大气痕量气体差分吸收光谱仪(星载仪器)搭载于太阳同步轨道卫星上,应用于定量监测全球空气质量变化以及污染气体的分布输运过程。星上定标是成像光谱仪获取数据定量化应用的基础,星载仪器采用太阳光定标方式和标准灯定标方式进行在轨定标。需对星上定标方式采用的定标机构进行分析和合理的设计,以保证星载仪器在轨定标的可靠性和精度。     

多通道扫描成像辐射计热设计

多通道扫描成像辐射计是FY-4卫星的主要载荷之一,可实现对地的多光谱观测.辐射计在轨运行期间承受复杂的外热流环境,为保证高质量的成像品质,必须对其进行有效的热设计,根据地球静止轨道和辐射计构型特点,分析了热设计的特点,并对仪器进行详细的热设计和热分析,计算结果证明了热设计方案的合理性.     

Satellite constellation design for 5G wireless networks of mobile communications

Satellite constellation design plays an important role in satellite networks. Network constellation system design can affect the effectiveness of current improvements of the communications link and the management of the entire network. The power requirement of the mobile stations and ground stations is very high in a geostationary Earth orbit communication system, which means the terrestrial terminal is hard to be made handheld for fifth generation mobile communications. The emergence of nongeostationary orbit satellites such as low Earth orbit satellites greatly compensates for the disadvantage of geostationary Earth orbit satellites. Based on the classical constellation design method, the orthogonal circular orbit constellation is proposed. The design objectives considered here are the following: global Earth coverage by low Earth orbit satellites, the duration of continuously covering one mobile station by one satellite is more than 9.57 min, the access satellite link duration time of the mobile station is more than 4.79 min, and the number of satellites and orbits is to be minimum.     

EMP susceptibility insights from aircraft exposure to lightning

Examines the interactions of natural lightning and the nuclear electromagnetic pulse (EMP) with aircraft. The propositions that one can use normal exposure to lightning to provide information on EMP protection, and deliberate exposure to lightning to test EMP protection are evaluated. The rarity of encountering lightning, its random occurrence and variability (necessitating extensive onboard instrumentation), and its apparent deficiency in energy at the high frequencies make the use of lightning for an EMP surveillance or test impractical     

静止轨道高分辨率相机Geo-Oculus方案论证研究

Geo-Oculus是欧空局于2008年开展的一项详细论证工作,它用于讨论在地球静止轨道上工作的对地观测卫星如何实现对全球环境与安全进行高空间分辨率和高时间分辨率监视的情况。Geo-.Oculus相机的主要任务是监视欧洲的灾害（水灾、山崩和暴风雨等）、火灾、海藻分布情况和水质,它还具备对石油泄漏和海岸线上的腐蚀物和沉淀物转移的监视能力。Geo-Oculus相机同时具有高空间分辨率和高时间分辨率的特点,其工作波段覆盖紫外、可见、近红外、短波红外和远红外区域,并可被细分为二十多个通道。该相机的可见光通道的地面分辨率可达到21m,紫外通道的为40m,而远红外通道的为750 m。该相机方案论证从工作模式、波段、光学分辨率和焦平面选型等方面展开。这项论证工作是针对静止轨道高分辨率相机方案研究的一个很好的案例,为下一步的详细设计和研制工作奠定了基础。     

风云二号B星星载扫描辐射计水汽通道定标方法

FY-2B静止气象卫里扫描辐射计水汽通道发射前定标在实验室真空罐内进行．发射在轨后,可以利用里上黑体监视探测器性能变化,但由于呈上黑体光路与目标光路不同,无法进行水汽通道的在轨全光路定标．介绍了FY-2B水汽通道的发射前定标、利用在轨电定标确定量化关系进行的定标处理以及与NOAA-17卫里HIRS／3通道12的相对定标方法．     

FY-4大气垂直探测仪扫描镜的太阳入侵研究

针对FY-4三轴稳定静止卫星上遥感器的夜间太阳入侵问题,建立了星上遥感器的太阳辐照模型,由此计算了星上任意面元的太阳入射角系数和太阳辐射.针对其上的大气垂直探测仪结合遮光罩实际设计参数,分析了扫描镜的每日太阳入射角系数、太阳辐射、太阳入侵的时刻、入侵持续时间以及接受的太阳辐照的年变化曲线,并与GOES-8(地球静止轨道...     

A satellite switched CDMA system for fixed service communications

Satellite-switched code-division multiple access is a system proposed for geostationary fixed satellite service. SS/CDMA provides both multiple access and switching to a multibeam satellite. In this article we present the system architecture and performance. The SS/CDMA consist of the common air interface (CAI) and the onboard code switching mechanism. The CAI provides signaling control and traffic channels. Traffic channel access and modulation is based on a spectrally efficient CDMA scheme. The satellite code-division switch (CDS) routes calls from an uplink to a downlink beam without onboard demodulation and channel decoding. This system operates with demand assignment control; that is, channel bandwidth and switch connections are only assigned per user request. The system can offer a wide variety of bit rates with wireline quality of service. The services provided are circuit-switched calls for voice data and video, and packet-switched for data. As shown, the proposed SE-CDMA can achieve high capacity and very low bit error rates at low signal-to-noise ratio. Also, the innovative switching technique can provide low complexity and achieve high throughput for all services     

Key payload technologies for future satellite personal communications: A European perspective

This paper deals with satellite payload architectures adequate for the provision of universal mobile telecommunication services (UMTS) by medium altitude earth and geostationary orbit (MEO and GEO) satellites. The payload concept introduced is based on a transparent transponder with onboard digital signal processing (DSP) operations and digital beamforming at the traffic carrier level (narrowband beamforming). The emphasis of the paper is on key design aspects and technology considerations of the payload processor unit (PPU), which includes multiplexing/demultiplexing and digital beamforming operations, and on the antenna and RF signal handling subsystems. For completeness, a review on the European digital technology is also presented. The development of such a payload architecture is in line with present and planned activities of the European Space Agency (ESA) for MEO and GEO orbit systems, which are also implicitly discussed in the paper.