BD GPS GLONASS GALILEO多星座卫星导航信号模拟器
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全球卫星导航定位系统GNSS介绍全球卫星导航定位系统GNSS介绍2010-12-17 17:01全球卫星导航定位系统(GNSS=Global Navigation Satellite System)是一种以卫星为基础的无线电导航系统。
系统可发送高精度、全天时、全天候、连续实时的导航、定位和授时信息,是一种可供海陆空领域的军民用户共享的信息资源。
卫星导航定位是指利用卫星导航定位系统提供位置、速度及时间等信息来完成对各种目标的定位、导航、监测和管理。
世界上最早的卫星导航系统是美国的子午仪导航系统(1964年开始运行)。
该系统的空间段由5-6颗卫星组成,采用多普勒定位原理,主要服务对象是北极星核潜艇,并逐步应用于各种海面舰船。
系统可在全球范围内提供全天候断续的二维定位。
系统建成后曾得到广泛应用,但该系统存在着定位实时性差、不能确定高程等缺陷,无法满足高精度、高动态用户的要求。
为满足日益增长的军事需要,20世纪60年代末70年代初,美国和前苏联分别开始研制全天候、全天时、连续实时提供精确定位服务的新一代全球卫星导航系统,至90年代中期全球卫星导航系统GPS和GLONASS均已建成并投入运行。
我国也建设了自主知识产权的北斗一号系统,并于2003年底正式开通运行。
欧盟筹建的GALILEO全球卫星导航系统正在计划实施之中。
卫星导航系统的出现,解决了大范围、全球性以及高精度快速定位的问题,最早应用于军用定位和导航,为车、船、飞机等机动工具提供导航定位信息及精确制导;为野战或机动作战部队提供定位服务;为救援人员指引方向。
随着技术的发展与完善,其应用范围逐步从军用扩展到民用,渗透至国民经济各部门。
其中包括海上和沙漠中的石油开发、交通管理、个人移动电话定位、商业物流管理、渔业、土建工程、考古…,卫星导航系统已成为数字地球、数字城市的空间信息基础设施。
●美国全球定位系统GPS GPS于60年代末开始研制,1973年系统方案正式诞生,1994年建成实用卫星导航系统,耗资120多亿美元。
GNSS卫星导航实验系统GNSS卫星导航实验系统大致可分为两类:应用型实验箱、原理型实验箱。
先就这两种实验箱作简单介绍:一、应用型实验箱GNSS卫星导航应用型实验系统是为开展卫星导航应用的学习与实验而研发的,此实验系统方案分为室内和室外两部分。
室内实验系统通过系列化的GNSS实验工具,将GNSS接收机OEM各部分功能进行拆分、解剖,同时结合强大的嵌入式安卓开发平台,使教师及学生可以在真实设备、真实卫星信号环境下,亲自动手进行导航卫星应用实训。
室外实验系统包括CORS差分站建设及车联网平台应用开发,使学生对高精度定位技术应用更深刻的理解。
为学生毕业后,顺利进入相关领域、从事相关工作,提供坚实的理论基础及实践经验。
GNSS卫星导航应用型实验系统可广泛应用于物联网专业、通信专业、测绘专业等专业的教学、实验以及产品开发。
二、GNSS卫星导航应用型实验系统组成GNSS卫星导航应用型实验系统是有多个设备组合而成的实验系统,其中包括:北斗/gps卫星导航信号转发系统北斗/gps双模手持终端北斗/gps高精度卫星接收天线北斗短报文开发一体机LT20051北斗/gps应用型教学实验箱GNSS实验室高精度差分源北斗/gps车辆远程监控调度平台卫星导航教学模块三、北斗/gps卫星导航应用型实验系统实验内容对于教学来说,能够进行哪些实验,是教师和学生们需要关注的事情,GNSS卫星导航应用型教学实验系统,主要是能够让学生学习到一些基础的应用,通过实验加以了解。
对此,莱特科技卫星导航应用型实验系统主要能实现的实验有哪些呢:1、北斗/gps定位原理实验(NMEA数据解析实验)2、GIS应用实验3、传感器应用实验4、综合应用实验(北斗/gps车辆远程监控调度实验)5、北斗/gps手持机应用实验6、高精度定位应用实验7、北斗短报文通讯实验8、惯导应用实验9、安卓通讯基础实验10、PC通讯基础实验通过利用卫星导航应用型实验系统学习后,将会更好的了解到北斗导航的应用有哪些,学习这些应用的实验过程,并且通过仿真实验能够更好的学习这些卫星导航应用的实验过程。
北斗接收机定位校准试验郭建麟;彭军;何群;孙丰甲;李娜娜【摘要】The development of Beidou Satellite navigation system triggered a wave of Beidou receivers development at home and a-broad. Users pay more attention to the performance and reliability of Beidou receivers, and the calibration of the Beidou receivers has become an urgent issue. This paper introduces several calibration methods of positioning accuracy for Beidou receivers, and compares these methods through calibration experiments.%随着北斗卫星导航系统的发展,引发了国内外北斗接收机研制的热潮,用户更多地关注北斗接收机的性能和可靠性,因此北斗接收机的校准就成为亟待解决的问题。
本文首先介绍了目前国内常用的几种北斗接收机定位精度的校准方法,然后通过校准试验来对比这几种方法的优缺点。
【期刊名称】《计测技术》【年(卷),期】2015(000)004【总页数】4页(P58-61)【关键词】北斗接收机;校准;定位精度【作者】郭建麟;彭军;何群;孙丰甲;李娜娜【作者单位】中航工业北京长城计量测试技术研究所,北京100095;中航工业北京长城计量测试技术研究所,北京100095;中航工业北京长城计量测试技术研究所,北京100095;中航工业北京长城计量测试技术研究所,北京100095;中航工业北京长城计量测试技术研究所,北京100095【正文语种】中文【中图分类】TB93Key words:Beidou receiver;calibration;positioning accuracy北斗卫星导航系统与GPS,GLONASS和Galileo统称为全球导航卫星系统(GNSS),是我国正在实施且自主研发的全天候、全天时提供卫星导航定位信息的区域导航系统,可为各类用户提供高精度、高可靠的定位、导航、授时服务[1]。
labsat双星模拟器使用说明书LabXXX双星模拟器说明书LabXXX录制和回放真实世界数据,允许在受控条件下进行真实和可重复的测试。
信号伪差(包括多路径、电离层效应)和信号断续均被复制,并不限定测试所用卫星数量。
传统测试通常需要多次驾车穿行同一路线,每次测试时的状况和卫星星座均会不同。
这就使复制和查找所测试装置的软件错误或接收问题,是个挑战。
使用LabXXX 可节省大量工作时间,让您无须离开测试台便可快速确定错误及核实“案例”。
一项十分有用的功能是,可使用LabXXX 上的高速数字端口录制和回放额外数据流。
如此以来,CAN总线数据、RS22信号或数字事件触发器就能在回放时完全同步,为您的研究室模拟带来全新的现实级别。
LabXXX 接收来自标准卫星天线的信号,但并不处理接收到的每个信号以计算出定位,然后以*带宽将原始卫星信号数字化并保存至移动SD卡或USB硬盘。
LabXXX 的射频(RF)输出随后连接至所测试装置的天线输入,录制的信号以回放成射频信号。
所测试装置随后开始跟踪卫星,如同沿着LabXXX 在原始录制期间所行经的相同路线行驶一样。
一键录制/回放使LabXXX 十分易于操作。
它构造坚固,并内置电池和清晰显示屏,LabXXX 可轻松应用于您的产品在日常使用中所经历的相同环境,只需少量或无需培训。
包含预录制和模拟的世界各地的免费文件库,让您能尽快做好准备和开始操作。
每款LabXXX双星座GNSS信号模拟器均可调谐至以下种用户可选频率之一: 1. 1575.420 MHz – GPS L1、Galileo E1、SBAS、QZSS 2. 1602.000 MHz - GLONASS L1 3. 1561.098 MHz - 北斗 B1用户可以自己生成测试场景,可以使用人工信号生成自己的自定义测试场景,XXXGen软件可让您用谷歌地图快速绘制路线,然后自动生成射频文件,再将该文件传送至LabXXX 上的SD卡并进行回放。
卫星导航的基本原理是:测量至4个卫星的距离,建立测量方程,固定系统时间和由星历导出的卫星坐标,估算用户的三维坐标和钟差。
显然,得到的用户坐标是在星历所体现的坐标系。
每个卫星导航系统都有自己的坐标系,例如GPS 使用WGS —84,GLONASS 使用PZ —90,GALILEO 使用GTRF 。
使用不同的导航系统,用户坐标当属不同的坐标系。
坐标系属于一个导航系统的大地参考。
大地参考对导航系统是至关重要的。
大地参考,犹如导航系统的生命线。
没有大地参考,就没有导航系统;没有大地参考,就没有导航定位。
大地参考的性能,在很大程度上决定导航系统的性能,决定导航定位的性能。
一个导航系统的大地参考,除坐标系外,还有引力场模型、地球定向参数,以及导航定位的相关常熟、模型和算法等其他元素,这些元素完整的构成了一个导航系统的大地基准。
在所有这些元素中,坐标系是最基本,也是于用户最直接、最密切的元素。
GPS 导航系统的坐标系统介绍1、全球定位系统(GPS )。
由24颗卫星组成,分布在6条交点互隔60度的轨道面上,精度约为10米,军民两用,正在试验第二代卫星系统,GPS 测量常用的坐标系统:(1)WGS-84坐标系WGS-84坐标系是目前GPS 所采用的的坐标系统,GPS 所发布的星历参数就是基于此坐标系统的。
WGS-84坐标系统的全称是World Geodical System-84(世界大地坐标系-84),它是一个地心地固坐标系统。
WGS-84坐标系统由美国国防部制图局建立,于1987年取代了当时GPS 所采用的坐标系统-WGS-72坐标系统而成为GPS 的所使用的坐标系统。
WGS84坐标系统是GPS 定位系统采用的协议地球坐标系统,是目前精度最高的全球性大地测量坐标系统, GPS 所发布的星历参数就是基于此坐标系统的。
WGS-84坐标系的几何意义是:坐标系的原点位于地球质心,z 轴指向(国际时间局)BIH1984.0定义的协议地球极(CTP)方向,x 轴指向BIH1984.0的零度子午面和CTP 赤道的交点,y 轴通过右手规则确定。
卫星导航系统课程设计一、教学目标本课程旨在让学生了解卫星导航系统的基本概念、原理和应用,掌握GPS、GLONASS、Galileo和BeiDou等卫星导航系统的工作原理和信号处理方法,培养学生运用卫星导航技术解决实际问题的能力。
1.了解卫星导航系统的历史和发展;2.掌握卫星导航系统的基本原理;3.熟悉各类卫星导航系统的特点和应用;4.了解卫星导航信号的传播和接收。
5.能够运用卫星导航系统进行定位和导航;6.能够分析卫星导航信号,提取有用信息;7.能够运用编程语言进行卫星导航软件的开发和调试;8.能够撰写卫星导航技术相关的实验报告。
情感态度价值观目标:1.培养学生对卫星导航技术的兴趣和好奇心;2.培养学生团队合作精神和实践能力;3.使学生认识到卫星导航技术在现代社会中的重要性和地位;4.培养学生关注国家卫星导航发展战略的意识。
二、教学内容本课程的教学内容主要包括以下几个部分:1.卫星导航系统概述:介绍卫星导航系统的历史、发展及现状,各类卫星导航系统的特点和应用。
2.卫星导航原理:讲解卫星导航系统的基本原理,包括信号传播、信号接收、定位算法等。
3.卫星导航系统信号处理:分析卫星导航信号的组成、调制方式及解调方法,讲解信号处理技术的应用。
4.卫星导航应用:介绍卫星导航技术在定位、导航、时间同步等方面的应用,以及在各行业中的实际应用案例。
5.卫星导航编程实践:通过编程语言(如Python)开展卫星导航软件的开发和调试,使学生掌握卫星导航技术的实际应用。
三、教学方法为了提高教学效果,本课程将采用多种教学方法相结合的方式,包括:1.讲授法:讲解卫星导航系统的基本概念、原理和应用,使学生掌握相关知识。
2.讨论法:学生针对卫星导航技术的热点问题进行讨论,培养学生的思维能力和团队协作精神。
3.案例分析法:分析卫星导航系统在实际应用中的案例,使学生了解卫星导航技术在生活中的重要作用。
4.实验法:开展卫星导航编程实践,使学生掌握卫星导航技术的实际应用。
北斗卫星导航系统民用全球信号多模多频宽带射频芯片技术要求和测试方法下载提示:该文档是本店铺精心编制而成的,希望大家下载后,能够帮助大家解决实际问题。
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北斗单系统及多 GNSS 系统组合全球卫星可用性分析吴有龙,杨忠,陈维娜,姚文进,陈闯,陈帅(1 金陵科技学院智能科学与控制工程学院,南京 211169;2 南京理工大学自动化学院,南京 210094;3 南京理工大学智能弹药技术国防重点学科实验室,南京 210094;4 沈阳理工大学装备工程学院,沈阳 110159)0 引言卫星定位技术已广泛应用于武器装备定位导航、卫星定轨、飞行状态监测、地壳运动监测和大地测量等领域[1-4]。
长期以来,基于卫星的定位技术主要依靠美国的全球定位系统(global positioning system, GPS),随着全球卫星导航系统(global navigation satellite system, GNSS)的快速发展,越来越多的跟踪站和星座被建立[5-6]。
近年来,俄罗斯的格洛纳斯(global navigation satellite system, GLONASS)、中国的北斗(BeiDou satellite navigationsystem, BDS)和欧盟的伽利略(GALILEO)系统蓬勃发展[7-11]。
未来的 GNSS 将以四大卫星导航系统的融合为全球用户提供服务。
多卫星星座信号融合优势明显,可见卫星数的增加,可显著提高定位精度,还可以减少由于地形、建筑、树木覆盖和卫星故障造成的 GNSS 服务盲区。
此外,由于测量冗余度较高,还可以提高位置解的可靠性[12-13]。
因此,人们进行了许多努力来研究多星座融合的优势,如多 GNSS 实时动态定位,单点定位和精密单点定位[14-16]。
许多工作是基于几十个甚至几个站点的数据集,这些数据集仅仅覆盖了有限的经纬度地区,需要进一步了解和研究当前全球范围内 GNSS 星座的定位性能。
对于卫星导航定位技术,卫星的可见性和位置精度因子(position dilution of precision, PDOP)可以作为评价定位性能优劣的重要指标[2,8,11,16]。
GPS与北斗卫星导航系统异同分析摘要:随着我国自主建设的北斗卫星导航系统已投入试运行服务,我国的综合国力大大增强。
该文详细介绍了gps与北斗卫星导航系统的系统组成、工作原理及功能。
同时具体分析了gps与北斗卫星导航系统的异同,指出了北斗系统的未来发展趋势。
关键词:gps 北斗卫星导航系统对比发展中图分类号:p228.4 文献标识码:a 文章编号:1674-098x(2013)03(c)-0-011 gps系统简介1.1 gps系统组成gps定位系统是一种卫星无线电导航系统,它由空间部分、地面监控部分和用户接收机三大部分组成。
gps的空间部分是由21颗工作卫星和3颗备用卫星组成,它位于距地表20200 km的上空,均匀分布在6个轨道面上,轨道倾角为55 °。
卫星的分布使得在全球任何地方、任何时间都可观测到4颗以上的卫星,并能在卫星中预存导航信息。
地面监控部分主要由1个主控站、3个注入站、5个监测站组成,主要负责收集由卫星传回的讯息,并计算卫星星历、相对距离,大气校正等数据。
用户接收机主要接收gps卫星发射信号,获得必要的导航和定位信息,经信号变换、放大和处理,完成定位、导航、跟踪、测绘及定时工作。
1.2 gps系统工作原理gps导航系统的基本原理是测出已知位置的卫星到用户接收机之间的距离,然后综合多颗卫星的数据就可以知道接收机的具体位置。
卫星的位置可以根据星载时钟所记录的时间在卫星星历中查出,用户到卫星的距离则通过记录卫星信号传播到用户所经历的时间,再将其乘以光速得到。
当gps卫星正常工作时,会不断地用二进制码元组成的伪码发射导航电文。
当用户接受到导航电文时,提取出卫星时间并将其与自己的时钟作对比便可得知卫星与用户的距离,再利用导航电文中的卫星星历数据推算出卫星发射电文时所处位置,用户在wgs-84大地坐标系中的位置速度等信息便可得知。
2 北斗卫星导航系统简介2.1 北斗卫星导航系统组成及功能北斗卫星导航系统(compass)是我国自行研制开发、独立运行的全球卫星导航系统。
GNSS卫星信号模拟器数学模型的研究与软件实现开题报告一、研究背景及意义全球导航卫星系统(GNSS)是一种通过卫星信号传送定位和时间信息的系统,包括美国的GPS、俄罗斯的GLONASS、欧洲的Galileo、中国的北斗等。
在很多领域,如航空、交通、军事和地质勘探等,都有广泛应用。
GNSS卫星信号模拟器是一种模拟GNSS卫星信号的设备或软件,可以用于GNSS接收机的测试、算法验证、产品开发等。
GNSS卫星信号模拟器的数学模型是实现模拟器功能的基础,主要包括两部分:信号传播模型和信号特性模型。
信号传播模型描述了GNSS信号在大气和电离层中的传播过程,以及在无线电传输中的传输过程。
信号特性模型描述了GNSS信号的频率、相位、功率、时间变化等特性。
这些模型的准确度和合理性对于GNSS卫星信号模拟的精度和可靠性至关重要。
二、研究内容和目标本论文的研究内容为GNSS卫星信号模拟器数学模型的研究和软件实现。
主要针对以下问题展开研究:1. GNSS卫星信号传播模型的研究和改进。
根据大气和电离层等影响因素,建立精确的信号传播模型,提高信号传播的准确度。
2. GNSS卫星信号特性模型的研究和改进。
通过分析GNSS信号的相关数据,建立更加准确的信号特性模型,提高信号模拟的精度。
3. GNSS卫星信号模拟器软件的开发。
基于上述两个模型,开发模拟GNSS卫星信号的软件,实现信号的模拟和应用测试等功能。
本论文的研究目标是建立准确的GNSS卫星信号模拟器数学模型,提高信号模拟的精度和可靠性,为GNSS卫星信号应用提供更加有效和可靠的测试手段。
三、研究方法和步骤本论文采用的研究方法主要包括理论分析、仿真计算和软件开发三个方面。
具体步骤如下:1. 文献综述。
对于GNSS卫星信号模拟器的相关研究和技术现状进行了综述,明确了研究的方向和内容。
2. 信号传播模型的研究。
根据大气和电离层等影响因素,建立准确的信号传播模型,并进行相关的数学分析。
多模导航模拟器时间同步控制系统设计与实现张金龙;张波;李署坚【摘要】在多模导航模拟器设计过程中,针对控制信息数据包和中频板卡信号产生时间同步控制的问题,设计了一种应用于基于软件无线电体系架构多模导航信号模拟器的时间同步控制系统;该系统通过由系统计时板对外设板卡同步触发启动控制,驱动软件与外设板卡1 s时隙同步控制,以及驱动软件向外设板卡传输数据包的同步控制,实现对各系统频点的时间同步控制;通过联合定位测试结果表明,采用该控制系统的多模导航模拟器的各系统频点的输出信号是时间同步的,并且该控制系统还具有各系统频点时间同步精度高和系统复杂度低等优点.【期刊名称】《计算机测量与控制》【年(卷),期】2015(023)012【总页数】4页(P4019-4022)【关键词】多模导航;时间同步;联合定位【作者】张金龙;张波;李署坚【作者单位】北京航空航天大学电子信息工程学院,北京 100191;北京航空航天大学电子信息工程学院,北京 100191;北京航空航天大学电子信息工程学院,北京100191【正文语种】中文【中图分类】TN967.1随着全球卫星导航系统的快速发展和广泛应用,对于导航信号模拟器的相关研究也不断升温。
作为多模导航接收机开发与验证的重要工具,近年来多模导航信号模拟器的研制成为全球导航卫星系统(global navigation satellite system, GNSS)领域的研究热点之一,国内外学者对此做了大量的研究工作。
由于国内多模导航信号模拟器的研制起步较晚,相关技术仍较国外有很大差距,具有自主知识产权的已经产品化的多模导航信号模拟器依然很少。
针对多模导航模拟器的时间同步控制问题,本文给出了多模导航信号模拟器中时间同步控制系统详细设计方案,该方案通过由系统计时板对外设板卡同步触发启动控制、驱动软件与外设板卡1 s时隙同步控制、驱动软件向外设板卡传输数据包的同步控制,实现对各系统频点的时间同步的控制,并且能够支持多模导航信号模拟器长时间持续稳定的工作。
ConsultativeCommittee for Space Data SystemsREPORT CONCERNING SPACEDATA SYSTEM STANDARDSTELEMETRYSUMMARY OFCONCEPT AND RATIONALECCSDS 100.0-G-1GREEN BOOKDECEMBER 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEAUTHORITY* * * * * * * * * * * * * * * * * * * * * * * * **Issue:Green Book, Issue 1**Date:January 1987**Location:CCSDS Plenary Meeting**November 1986**Frascati, Italy** * * * * * * * * * * * * * * * * * * * * * * * *This report reflects the consensus of the technical panel experts of the following member Agencies of the Consultative Committee for Space Data Systems (CCSDS):o British National Space Centre (BNSC)/United Kingdom.o Centre National D'Etudes Spatiales (CNES)/France.o Deutsche Forschungs-u. Versuchsanstalt fuer Luft und Raumfahrt e.V (DFVLR)/ West Germany.o European Space Agency (ESA)/Europe.o Indian Space Research Organization (ISRO)/India.o Instituto de Pesquisas Espaciais (INPE)/Brazil.o National Aeronautics and Space Administration (NASA)/USA.o National Space Development Agency of Japan (NASDA)/Japan.The panel experts of the following observer Agencies also technically concur with this report:o Chinese Academy of Space Technology (CAST)/People's Republic of China.o Department of Communications, Communications Research Centre(DOC-CRC)/Canada.This report is published and maintained by:CCSDS SecretariatCommunications and Data Systems Division (Code-TS)National Aeronautics and Space AdministrationWashington, DC 20546, USAIssue 1i December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEFOREWORDThis CCSDS report presents the conceptual framework and rationale for the CCSDS Telemetry System. The background information provided here will be found helpful in understanding the two CCSDS technical Recommendations for Telemetry.This report supports CCSDS Recommendations for "Packet Telemetry" (Reference [1]) and "Telemetry Channel Coding" (Reference [2]).Through the process of normal evolution, it is expected that expansion, deletion or modification to this report may occur. This report is therefore subject to CCSDS document management and change control procedures which are defined in Reference [3].Questions relative to the contents or status of this report should be addressed to the CCSDS Secretariat.Issue 1ii December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEDOCUMENT CONTROLIssue Title Date Status/Remarks CCSDS 100.0-G-1Report Concerning Space December Current IssueData System Standards,1987Telemetry: Summary ofConcept and Rationale, Issue 1Issue 1iii December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE[This page intentionally left blank.]Issue 1iv December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEIssue 1v December 1987CONTENTS Sections PageREFERENCES......................................................................................................... vii 1DOCUMENT PURPOSE, SCOPE AND ORGANIZATION................................. 1-11.1PURPOSE...................................................................................................... 1-11.2SCOPE............................................................................................................ 1-11.2ORGANIZATION.......................................................................................... 1-12OVERVIEW OF CCSDS TELEMETRY SYSTEM.............................................. 2-12.1INTRODUCTION.......................................................................................... 2-12.2TELEMETRY SYSTEM CONCEPT............................................................. 2-22.2.1PACKETIZATION LAYER............................................................... 2-32.2.2SEGMENTATION LAYER.............................................................. 2-32.2.3TRANSFER FRAME LAYER.......................................................... 2-32.2.4CHANNEL CODING LAYER.......................................................... 2-52.2.5RELATIONSHIP BETWEEN TELEMETRY ANDTELECOMMAND SYSTEMS........................................................... 2-73TELEMETRY SYSTEM DESCRIPTION AND RATIONALE............................. 3-13.1PACKET TELEMETRY................................................................................ 3-13.1.1INTRODUCTION.............................................................................. 3-13.1.2TELEMETRY SOURCE PACKET.................................................... 3-23.1.3FLOW CONTROL MECHANISMS................................................. 3-63.1.4TELEMETRY TRANSFER FRAME................................................ 3-103.2TELEMETRY CHANNEL CODING............................................................ 3-153.2.1INTRODUCTION.............................................................................. 3-153.2.2CONVOLUTIONAL CODE.............................................................. 3-193.2.3PERIODIC CONVOLUTIONAL INTERLEAVING........................ 3-193.2.4REED-SOLOMON CODE ................................................................ 3-20AnnexesAGLOSSARY OF TELEMETRY TERMINOLOGY............................................... A-1B"APPLICATION NOTES" FOR PACKET TELEMETRY.................................... B-1C SUMMARY OF SEGMENTATION OPTIONS.................................................... C-1CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE Issue 1vi December 1987D TELEMETRY TRANSFER FRAME ERROR DETECTIONENCODING/DECODING GUIDELINE................................................................ D-1Figures2-1Layered Telemetry Service Model.......................................................................... 2-42-2Telemetry Data Structures....................................................................................... 2-62-3Telemetry/Telecommand Relationships.................................................................. 2-83-1Telemetry Data Flow............................................................................................... 3-33-2"Source Packet" (Version 1) Format....................................................................... 3-43-3Telemetry Segment (Version 2) Format.................................................................. 3-93-4Telemetry Transfer Frame Format........................................................................... 3-113-5Coding System Block Diagram................................................................................ 3-173-6Performance of Various Codes in a Gaussian Channel........................................... 3-18D-1Encoder.................................................................................................................... D-4D-2Decoder................................................................................................................... D-4TableC-1Summary of Segmentation Options........................................................................ C-3CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEREFERENCES[1]"Packet Telemetry", Recommendation CCSDS 102.0-B-2, Issue 2, Blue Book,Consultative Committee for Space Data Systems, January 1987 or later issue. [2]"Telemetry Channel Coding", Recommendation CCSDS 101.0-B-2, Issue 2, Blue Book,Consultative Committee for Space Data Systems, January 1987 or later issue. [3]"Reference Model of Open Systems Interconnection", International Organization forStandardization, Draft International Standard DIS-7498, February 1982 or later issue.[4]Rice, R.F., and Hilbert, E., US Patent 3988677, October 26, 1976.[5]Morakis, J.C., "Discussion of Synchronization Words", NASA Technical Memorandum86222, NASA-Goddard Space Flight Center, Greenbelt, Maryland, May 15, 1985. [6]"Procedures Manual for the Consultative Committee for Space Data Systems", Issue 1,Consultative Committee for Space Data Systems, August 1985 or later issue.[7]Cager, R., "Spacecraft Identification Requirements Analysis", CCSDS Panel 1-CTelecommand Action Item 6.26, June 3-7, 1985.[8]"Telecommmand: Summary of Concept and Service", Report CCSDS 200.0-G-6, Issue 6,Green Book, Consultative Committee for Space Data Systems, January 1987 or later issue.[9]"Telecommand, Part 2: Data Routing Service, Architectural Specification",Recommendation CCSDS 202.0-B-1, Issue 1, Blue Book, Consultative Committee for Space Data Systems, January 1987 or later issue.[10]Rice, R.F., Channel Coding and Data Compression System Considerations for EfficientCommunication of Planetary Imaging Data, Technical Memorandum 33-695, NASA-Jet Propulsion Laboratory, Pasadena, California, June 15, 1974.[11]Rice, R.F., End-to-End Imaging Rate Advantages of Various Alternative CommunicationSystems, JPL Publication 82-61, NASA-Jet Propulsion Laboratory, Pasadena, California, September 1, 1982[12]Rice, R.F., Mission Science Value/Cost Savings from the Advanced ImagingCommunications System, JPL Publication 84-33, NASA-Jet Propulsion Laboratory, Pasadena, California, July 15, 1984.Issue 1vii December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE [13]Miller, R.L., et al., On the Error Statistics of Viterbi Decoding and the Performance ofConcatenated Codes, JPL Publication 81-9, NASA-Jet Propulsion Laboratory, Pasadena, California, September 1, 1981.[14]Odenwalder, J.P., Concatenated Reed-Solomon/Viterbi Channel Coding for AdvancedPlanetary Missions, Final Report, Contract 953866, December 1, 1974.[15]Liu, K.Y., The Effects of Receiver Tracking Phase Error on the Performance ofConcatenated Reed-Solomon/Viterbi Channel Coding System, JPL Publication 81-62, NASA-Jet Propulsion Laboratory, Pasadena, California, September 1, 1981.[16]Odenwalder, J.P., et al., Hybrid Coding Systems Study, Final Report, NASA-AmesResearch Center Contract NAS2-6722, Linkabit Corporation, San Diego, California, September 1972.[17]Perlman, M., and Lee, J.J., Reed-Solomon Encoders - Conventional vs Berlekamp'sArchitecture, JPL Publication 82-71, NASA-Jet Propulsion Laboratory, Pasadena, California, December 1, 1982.[18]Tracking and Data Relay Satellite System (TDRSS) Users' Guide, STDN 101.2, Rev. 5,NASA-Goddard Space Flight Center, Greenbelt, Maryland, September 1984.The latest issues of CCSDS documents may be obtained from the CCSDS Secretariat at the address indicated on page i.Issue 1viii December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE 1DOCUMENT PURPOSE, SCOPE AND ORGANIZATION1.1PURPOSEThis report contains the concept and supporting rationale for the Telemetry System developed by the Consultative Committee for Space Data Systems (CCSDS). It has been prepared to serve two major purposes:(1)To provide an introduction and overview for the Telemetry System concept uponwhich the detailed CCSDS Telemetry Recommendations (References [1] and [2]) arebased.(2)To summarize the specific individual Recommendations and to supply the supportingrationale.This document is a CCSDS informational Report and is therefore not to be taken as a CCSDS Recommendation for Data System Standards.1.2 SCOPEThe concepts, protocols and data formats developed for the Telemetry System described herein are designed for flight and ground data systems supporting conventional, contemporary free flyer spacecraft. Data formats are designed with efficiency as a primary consideration, i.e., format overhead is minimized. The results reflect the consensus of experts from many space agencies.1.3 ORGANIZATIONAn overview of the CCSDS Telemetry System is presented in Section 2, which introduces the notion of architectural layering to achieve transparent and reliable delivery of scientific and engineering sensor data (generated aboard remote space vehicles) to the users located in space or on Earth.Section 3 presents a more detailed description of the Telemetry System and rationale for the two specific CCSDS Telemetry Recommendations.Annex A presents a Glossary in order to familiarize the reader with the terminology used throughout the CCSDS Telemetry System.Issue 1Page 1-1December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE Annex B contains application notes which describe how a Project may implement complete or partial compatibility with the CCSDS Telemetry Recommendations [1] and [2].Annex C summarizes the segmentation options available for segmenting very long Source Packets.Annex D is a guideline for Transfer Frame error detection coding.Issue 1Page 1-2December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE 2OVERVIEW OF CCSDS TELEMETRY SYSTEM2.1 INTRODUCTIONThe purpose of a telemetry system is to reliably and transparently convey measurement information from a remotely located data generating source to users located in space or on Earth. Typically, data generators are scientific sensors, science housekeeping sensors, engineering sensors and other subsystems on-board a spacecraft.The advent of capable microprocessor based hardware will result in data systems with demands for greater throughput and a requirement for corresponding increases in spacecraft autonomy and mission complexity. These facts, along with the current technical and fiscal environments, create a need for greater telemetering capability and efficiency with reduced costs. Traditionally, most of the telemetry resources used by a science mission have been wholly contained within a cognizant Project office and, with the exception of the tracking network, are completely dedicated to that mission. The lack of effective standardization among various missions forces the "multi-mission" tracking network to implement the lowest level of telemetry transport service, i.e., bit transport. Higher level data delivery services, oriented more toward computer-to-computer transfers and typical of modern day commercial and military networks, must be custom designed and implemented on a mission-to-mission basis.The intent of the CCSDS Telemetry System is not only to ease the transition toward greater automation within individual space agencies, but also to ensure harmony among the agencies, thereby resulting in greater cross-support opportunities and services.The CCSDS Telemetry System is broken down into two major conceptual categories: a "Packet Telemetry" concept (Reference [1]) and a "Telemetry Channel Coding" concept (Reference [2]).Packet Telemetry is a concept which facilitates the transmission of space-acquired data from source to user in a standardized and highly automated manner. Packet Telemetry provides a mechanism for implementing common data structures and protocols which can enhance the development and operation of space mission systems. Packet Telemetry addresses the following two processes:(1)The end-to-end transport of space mission data sets from source application processeslocated in space to distributed user application processes located in space or on Earth.(2)The intermediate transfer of these data sets through space data networks; morespecifically, those elements which contain spacecraft, radio links, tracking stationsand mission control centers as some of their components.Issue 1Page 2-1December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE The Packet Telemetry Recommendation contained in Reference [1] is primarily concerned with describing the telemetry formats which are generated by spacecraft in order to execute their roles in the above processes.Telemetry Channel Coding is a method by which data can be sent from a source to a destination by processing it in such a way that distinct messages are created which are easily distinguishable from one another. This allows reconstruction of the data with low error probability, thus improving the performance of the channel. The Telemetry Channel Coding Recommendation contained in Reference [2] describes several space telemetry channel coding schemes. The characteristics of the codes are specified only to the extent necessary to ensure interoperability and cross-support.Together, Packet Telemetry and Telemetry Channel Coding services provide to the user reliable and transparent delivery of telemetry information.2.2 TELEMETRY SYSTEM CONCEPTThe system design technique known as layering was found to be a very useful tool for transforming the Telemetry System concept into sets of operational and formatting procedures. The layering approach is patterned after the International Organization for Standardization's Open Systems Interconnection layered network model (Reference [3]), which is a seven layer architecture that groups functions logically and provides conventions for connecting functions at each layer. Layering allows a complex procedure such as the telemetering of spacecraft data to the users to be decomposed into sets of peer functions residing in common architectural strata. Within each layer, the functions exchange data according to established standard rules or "protocols". Each layer draws upon a well defined set of services provided by the layer below, and provides a similarly well defined set of services to the layer above. As long as these service interfaces are preserved, the internal operations within a layer are unconstrained and transparent to other layers. Therefore, an entire layer within a system may be removed and replaced as dictated by user or technological requirements without destroying the integrity of the rest of the system. Further, as long as the appropriate interface protocol is satisfied, a customer (user) can interact with the system/service at any of the component layers. Layering is therefore a powerful tool for designing structured systems which change due to the evolution of requirements or technology.A companion standardization technique that is conceptually simple, yet very robust, is the encapsulation of data within an envelope or "header". The header contains the identifying information needed by the layer to provide its service while maintaining the integrity of the envelope contents.Issue 1Page 2-2December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE Figure 2-1 illustrates the CCSDS Telemetry System in terms of a layered service model. It should be noted that the CCSDS Packet Telemetry and Telemetry Channel Coding Recommendations only address the five lower layers of this model.2.2.1PACKETIZATION LAYERWithin Packet Telemetry, spacecraft generated application data are formatted into end-to-end transportable data units called TM Source Packets. These data are encapsulated within a primary header which contains identification, sequence control and packet length information, and an optional trailing error control field. A TM Source Packet is the basic data unit telemetered to the user by the spacecraft and generally contains a meaningful quantity of related measurements from a particular source.2.2.2 SEGMENTATION LAYERTo provide assistance with data flow control, the Packet Telemetry Recommendation provides the capability to segment large packetized transportable data units into smaller communication oriented TM Source Packets (Version 1 format) or TM Segments (Version 2 format) for transfer through the space data channel. Consequently, the TM Source Packets and/or TM Segments are of proper size for placement into the data field of the data unit of the next lower layer.2.2.3 TRANSFER FRAME LAYERThe TM Transfer Frame is used to reliably transport Source Packets and Segments through the telemetry channel to the receiving telecommunications network. As the heart of the CCSDS Telemetry System, the TM Transfer Frame protocols offer a range of delivery service options. An example of such a service option is the multiplexing of TM Transfer Frames into "Virtual Channels" (VCs).The TM Transfer Frame begins with an attached frame synchronization marker and is followed by a primary header. The primary header contains frame identification, channel frame count information and frame data field status information.The transfer frame data field may be followed by an optional trailer containing an operational control field and/or a frame error control field. The first of these fields provides a standard mechanism for incorporating a small number of real-time functions (e.g., telecommand verification or spacecraft clock calibration). The error control field provides the capability for Issue 1Page 2-3December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEIssue 1Page 2-4December 1987PROVIDES USERS A METHOD TO INVESTIGATE PHYSICAL PHENOMENA BY USING THEIR INSTRUMENTS IN SPACE FOR DATA COLLECTION AND THEIR APPLICATION PROCESSES FOR ANALYSIS.PROVIDES TRANSLATION OF PHYSICAL MEASUREMENTS INTO SETS OF APPLICATION DATA UNITS.PROVIDES END-TO-END DELIVERY OF APPLICATION DATA UNITS.(OPTIONAL) PREPARES LONGER PACKETIZED DATA UNITS FOR MULTIPLEXING AND TRANSFER THROUGH A SPACE DATA CHANNEL.PROVIDES RELIABLE TRANSFER OF PACKETS AND SEGMENTS IN A COMMON STRUCTURE FOR THEIR TRANSPORT THROUGH THE SPACECRAFT-TO-GROUND COMMUNICATION LINK.PROTECTS TRANSFER FRAMES AGAINST ERRORS INDUCED DURING TRANSMISSION THROUGH THE NOISY PHYSICAL COMMUNICATIONS CHANNEL.PROVIDES THE PHYSICAL CONNECTION, VIA RADIO FREQUENCY SIGNALS, BETWEEN A TRANSMITTING SPACECRAFT AND THE RECEIVING YERSERVICE PROVIDED BY LAYER Figure 2-1: Layered Telemetry Service ModelCCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE detecting errors which may have been introduced into the frame during the data handling process.The delivery of transfer frames requires the services provided by the lower layers (e.g., carrier, modulation/detection, and coding/decoding) to accomplish its role.2.2.4 CHANNEL CODING LAYERSince a basic system requirement is the error-free delivery of the TM Transfer Frames, Telemetry Channel Coding is used to protect the transfer frames against telemetry channel noise-induced errors. Reference [2] describes the CCSDS Recommendataion for Telemetry Channel Coding, including specification of a convolutionally encoded inner channel concatenated with a Reed-Solomon block-oriented outer code (Reference [4]). The basic data units of the CCSDS Telemetry Channel Coding which interface with the layer below are the Channel Symbols output by the convolutional encoder. These are the information bits representing one or more transfer frames as parity-protected channel symbols.The RF channel physically modulates the channel symbols into RF signal patterns interpretable as bit representations. Within the error detecting and correcting capability of the channel code chosen, errors which occur as a result of the physical transmission process may be detected and corrected by the receiving entity.Full advantage of all CCSDS Telemetry System services could be realized if a Project complied with all CCSDS Recommendations. Alternatively, Projects can interface with any layer of the Telemetry System as long as they meet the interface requirements as specified in the two Recommendations (References [1] and [2]).Figure 2-2 illustrates how the various telemetry data structures map into one another. There is presently no attempt to define the data structures of the top two layers of the telemetry system;i.e., the Application Process layer and the System Management layer. Telemetry Source Packets may be segmented and placed into the data field of telemetry segments, which are preceded by a header. The Source Packets and/or the Segments are placed into the data field of the Transfer Frame which is preceded by a transfer frame header. If the specified Reed-Solomon code is used in the channel coding scheme, the transfer frame is placed into the Reed-Solomon data space of the Reed-Solomon codeblock, and the codeblock is preceded by an attached synchronization marker.Issue 1Page 2-5December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE2.2.5RELATIONSHIP BETWEEN TELEMETRY AND TELECOMMAND SYSTEMSA different level of understanding is revealed by considering interactions between the Telemetry System and other systems in the operational environment. In conceptual fashion, Figure 2-3 shows the balanced relationship between the Telemetry System and the uplink Telecommand System. The two systems work hand-in-hand to assure the transfer of user directives from the sending end (traditionally on the ground) to the receiving end (controlled process, device or instrument). Of course, the Telemetry System does a great deal more than simply returning command receipt status information to the sender: its usual function is to provide reliable, efficient transfer of all spacecraft data (housekeeping, sensor readings, etc.) back to users.Issue 1Page 2-7December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALEFigure 2-3: Telemetry/Telecommand RelationshipsIssue 1Page 2-8December 1987CCSDS REPORT CONCERNING TELEMETRY: SUMMARY OF CONCEPT AND RATIONALE 3TELEMETRY SYSTEM DESCRIPTION AND RATIONALE This section describes the services and protocols characterizing the Telemetry System and presents the rationale for detailed structure of the data units. The section is partitioned into the two major parts of the CCSDS Telemetry System: Packet Telemetry and Telemetry Channel Coding. Within the Packet Telemetry section, discussion is organized according to three main protocol and format areas: 1) TM Source Packet, 2) Source Packet Segmentation, and 3) TM Transfer Frame. The CCSDS Telemetry Channel Coding section is divided into the three main subject coding methods: 1) Convolutional Code, 2) Periodic Convolutional Interleaving, and 3) Reed-Solomon Code.3.1 PACKET TELEMETRY3.1.1 INTRODUCTIONPacket Telemetry represents an evolutionary step from the traditional Time-Division Multiplex (TDM) method of transmitting scientific, applications and engineering data from spacecraft sources to users located in space or on Earth. The Packet Telemetry process conceptually involves:(1)Encapsulating, at the source, observational data (to which may be added ancillarydata to subsequently interpret the observational data), thus forming an autonomous"packet of information in real time on the spacecraft.(2)Providing a standardized mechanism whereby autonomous packets from multipledata sources on the spacecraft can be inserted into a common "frame" structure fortransfer to another space vehicle or to Earth through noisy data channels, anddelivered to facilities where the packets may be extracted for delivery to the user. The Packet Telemetry process has the conceptual attributes of:(1)Facilitating the acquisition and transmission of instrument data at a rate appropriatefor the phenomenon being observed.(2)Defining a logical interface and protocol between an instrument and its associatedground support equipment which remains constant throughout the life cycle of theinstrument (bench test, integration, flight, and possible re-use).(3)Simplifying overall system design by allowing microprocessor-based symmetricdesign of the instrument control and data paths ("Telecommand Packets in, Issue 1Page 3-1December 1987。