1、随机信号全册配套完整课件随机信号全册配套完整课件前言 1. 张明友,张扬, “ 随机信号分析 ” . 电子科大出版社 , 2002年 . 2. 陆大经, “ 随机过程及其应用 ” 清华大学出版社 ,1986年 . 3. 王永德,王军, “随机信号分析基础 ” . 电子工业出版社,2003年 .教材： 常建平,李海林 “随机信号分析 ” . 科学出版社, 2006年 .参考书4.赵淑清,郑薇, “随机信号分析 ” . 哈工大出版社, 1999年n信号与消息n人们相互问询、发布新闻、广播、图像数据传递，其目的都是要把某些消息借一定的信号传送出去。n信号是消息的表现形式，消息则是信号的具体内容n历史
2、发展n1、古代n中国古代，烽火传送边疆警报n古西腊，火炬位置表示字符信号n击鼓鸣金，报送时刻，传达命令-声信号n信鸽、旗语、驿站n距离、速度、有效性、可靠性？n2、近代n1837年，Morse， 电报n1876年，Bell，电话n19世纪末，Hertz， 波波夫，马可尼，电磁波传送电信号n1901年，马可尼，横渡大西洋的无线电通信n从此，传送电信号的方通信方式得到了广泛应用和迅速发展n3、现代nGPS，精度10米以内n个人通信：呼叫、语音、图像、数据传输、网络 原始光通信n信号分类n描述信号的基本方式是写出它的数学表达式，为一时间函数，函数的图像称为信号的波形确定信号随机信号周期信号非周期信号
3、连续时间信号离散时间信号随机过程(信号) n自然界变化过程通常可分为确定过程和随机过程两大类, 随机信号分析是研究随机变化过程规律性的一门学科, 是电子科学与技术、信息与通信工程各专业的重点专业基础课。随机信号分析的理论是推动众多学科发展的重要基石, 这些学科也为随机信号分析提出了许多重要课题。n70 年代以前, 信号处理往往局限于平稳的、高斯的信号和噪声环境。 到80 年代中后期至今, 形成了一个崭新的非平稳、非高斯、非最小相位特性的随机信号分析与处理的理论框架, 并且以迅猛的速度在发展。本课程主要内容本课程主要内容n概率论基础概率论基础n 随机过程和随机序列随机过程和随机序列 n 随机信号
4、的频域分析随机信号的频域分析n 系统对随机信号的响应系统对随机信号的响应 n 窄带随机过程窄带随机过程 与其它课程的关系与其它课程的关系n是概率论课程的后续课程n错误错误1：概率论学的不好，就放弃了。：概率论学的不好，就放弃了。n错误错误2：概率论还可以，第一章可以不学。：概率论还可以，第一章可以不学。n是其它课程的基础课程，如：n图像处理、语音处理、信号检测、谱估计、自适图像处理、语音处理、信号检测、谱估计、自适应滤波、小波分析、雷达技术等应滤波、小波分析、雷达技术等n数字信号处理、通信原理、编码原理、线性控制数字信号处理、通信原理、编码原理、线性控制系统等系统等n考核办法考核成绩由平时成绩
5、与结课成绩两部分组成：n平时成绩：30%n平时作业及考勤： 15%n大作业：15%n结课考试成绩：70%n任课老师：韩雁飞n办公室：北教12-211n电话：24092437nEmail：机载监视系统机载监视系统Airborne Surveillance System课程简介n本课程性质：专业限选课，面向电子专业，内容不断更新，可直接为民航机载监视类设备原理提供基础知识和相关实验。n本课程安排： 学时：36学时（课堂教学28学时，实验8学时）n课堂教学内容：1.Airborne Weather Radar(WXR)2.Secondary Surveillance Radar(SSR)3.Traf
6、fic Collision Avoidance System(TCAS)4.Enhanced Ground Proximity Warning System(EGPWS)5.Automatic Dependent Surveillance-Broadcast(ADS-B)n教学目的： 了解民航机载监视相关设备的原理，掌握相关专业词汇。n教材：编写中 n成绩：考勤+作业：15%；实验：30%；考试：55%。11Civil Aviation English n行业性英语，其覆盖内容几乎包含了民用航空企业的所有部门n航空企业的雇佣条件大多包含英语水平，即使入职后，仍会进行民航英语学习，并且随着民航事
7、业的不断发展，各航空企业对在职员工民航英语要求也越来越高。n行业特色明显 - 缩写非常普遍 - 专业词汇较多 - 维修手册(AMM,FIM,CMM,WDM等)，试航指令（AD），服务通告（SB）等都是英文。12缩写（Abbreviation）nExample 1：AOCAOC： Airline Operational Communications AOC ：Airline Operation Control AOC： Aircraft Operations Centre AOC： Aircraft Operating CompanyAOC： Aeronautical Operational C
8、ontrol AOC ：Aeronautical Operational CommunicationsAOC ：Air Operators Certificate AIS(En) Aeronautical Information Services SIA (Fr) Service dInformation AronautiqueACC(En) Area Control Centre CCR(Fr) Centre de Contrle RgionalvExample 2：AIS, ACC13专业词汇（Specialized vocabulary）nTaxiwaynCabinnPitch/roll
9、/yawnAltitudenNautical milenApproachnflight/aircraft/plane/aeroplane/airplane/jet/helicopter/glider/UAV14Introduction to Airborne Surveillance System中国民航大学中国民航大学电子信息工程学院电子信息工程学院Outline1 General introduction2 Surveillance functions3 Surveillance sensors16Outline1 General introduction2 Surveillance fu
10、nctions3 Surveillance sensors17General introductionn The life of a flightSafety?Reminder on Air Traffic Servicesn The objectives of the Air Traffic Services(ATS) Ob1： prevent collisions between aircraft（避撞） Ob2： prevent collisions between aircraft on the manoeuvring area and obstructions on that are
11、a（避撞） Ob3：expedite and maintain an orderly flow of air traffic（有序） Ob4：provide useful advice and information for the safe and efficient conduct of flights（安全高效） Ob5：notify appropriate organizations regarding aircraft in need of search and rescue aid, and assist such organizations as required（预警）Remi
12、nder on Air Traffic Servicesn ATS comprise the three following services(1) The air traffic control service, : Area control service: the provision of air traffic control service for controlled flights, in order to accomplish objectives 1 & 3; Approach control service: the provision of air traffic con
13、trol service for arrival or departure, in order to accomplish objectives 1 &3; Aerodrome control service: the provision of air traffic control service for aerodrome traffic, in order to accomplish objectives 1, 2 & 3.(2)The flight information service, to accomplish objective 4.(3)The alerting servic
14、e, to accomplish objective 5.Relationship21Surveillance itemsnPSR(WXR)nSSR(ATCRBS)nSDPS, FDPSnA-SMGCSnSafety nets(STCA(TCAS),MSAW(EGPWS)nADSnMLAT(Multilateration) and WAMn 22STCA23Short Term Conflict AlertMSAW24Minimum Safe Altitude WarningICAO(国际民用航空组织)25International Civil Aviation OrganizationInt
15、ernational Civil Aviation Organization Appendix 10 : Aeronautical CommunicationsAppendix 10 : Aeronautical Communications Book 1 Radio Navigation Aids Book 1 Radio Navigation Aids Book 2 Communication Procedures including those with PANS Book 2 Communication Procedures including those with PANS Stat
16、usStatus Book 3 Communications Systems Book 3 Communications Systems Book 4 Surveillance Radar and Collision Avoidance SystemsBook 4 Surveillance Radar and Collision Avoidance Systems Book 5 Aeronautical Radio Frequency Spectrum UtilizationBook 5 Aeronautical Radio Frequency Spectrum Utilization htt
17、p:/www.icao.inthttp:/www.icao.intSurveillance structure26Outline1 General introduction2 Surveillance functions3 Surveillance sensors272 Surveillance functionsSurveillance purposes within CNSSurveillance conceptsnCommunicationControl aircraft trajectories by giving pilots instructionsnNavigationProvi
18、de pilots means to follow the requested trajectories on their own nSurveillanceKnow where aircrafts are at a given instantKnow there they are going to29See AMM to revise and distinguishCNS ServicesCommunication Fixed/Mobile Service Voice Communication Data-CommunicationNavigation Ground Based Naviga
19、tion Systems ILS, VOR, DME, VDF Airspace Based Navigation Systems GPS30Surveillance Non Cooperative PSR Cooperative SSR, MLAT Dependant ADS/B/CPhases of Flight31Associated Services32Surveillance functions Surveillance with COM and NAV is an essential element ofintegrated ATM operations Provides the
20、necessary information to ensure safe and expeditious sequencing of air traffic control Real time report of air situation : Position and identification of moving targets Detection and alerts for conflict situation (safe horizontal/vertical separation) Appropriate data processing, distribution and dis
21、plays to the users Ground: controller position Airborne: pilot position33Outline1 General introduction2 Surveillance functions3 Surveillance sensors34Surveillance sensorsnAirborne WXRnSSR transpondernTCASnEGPWSnADS-B35WXR: Airborne weather radarWXR provides the flight crew with a representation of w
22、eather (compensated for a/c attitudes): - Localization (tilt and distance) and density of water particles - Turbulence information and wind shear detection through particle horizontal speed detection36反射率(mm/h)颜色显示无雨区50.8Airborne WXR37SSR and transponder38TCAS/ACASnTCAS：Trafic Collision Avoidance Sy
23、stemnACAS：Airborne Collision Avoidance System39EGPWS/TAWSvEGPWS: Enhanced Ground Proximity Warning SystemvTAWS: Terrain Awareness Warning System40ADS-BnADS-B: Automatic Dependent Surveillance Broadcast41Sensors Position42Sensors Position43Sensors Position44PerspectivenAESS(Aircraft Environment Surve
24、illance System)= TAWS + TCAS + ATC transponder + Weather radar within a single equipment, also called ISS(Integerate Surveillance System). From 5 surveillance systems (22 to 30 MCU)+ 7 antennas to45本课程整体安排1 Introduction (2)2 Airborne Weather Radar (10)3 SSR transponder (6)4 TCAS/ACAS (4)5 EGPWS/TAWS
25、 (4)6 ADS-B (2)46Basics for Aviation - Alphabet47Basics for Aviation -unitnHorizontal distance (Nautical Mile): 1 NM = 1852 m nSpeed (Knot): 1 kt = 1 NM / hnVertical distance (Feet) : 1 ft = 0.3048 m 48Airborne Weather Radar(WXR)Airborne Weather Radar(WXR)中国民航大学中国民航大学电子信息与自动化学院电子信息与自动化学院ContentsCon1
26、：Radar principleCon2: Introduction to WXRCon3：Ranging,Azimuth measurement,MTICon4：Transmitter,ReceiverCon5：Antenna,CP,Display50Airborne Weather Radar(WXR)Airborne Weather Radar(WXR) Con1 Con1：Radar principleRadar principleOutlines For Con10 雷达历史1 雷达的定义和类型2 雷达探测目标的原理3 雷达基本组成4 雷达方程52Con1-0 雷达历史 Why we
27、 need radar？nATC functionProvision of safe and expeditious sequencing of traffic;Provision of safe horizontal and vertical separation;Safe meaning: No collision53Separation minima54Former controller55Current controller56PPI: Plan Position Indicator5758PPI and cluttersPPI and cluttersCon1-1 雷达的定义和类型R
28、ADAR: RAdio Detection And Ranging雷达：无线电探测与测距One of the most important surveillance sensors59Con1-1 雷达的定义和类型60PSR: Primary Surveillance RadarSSR: Secondary Surveillance Radar雷达频段WXR: 93009375Mhz61Con1-1 雷达的定义和类型Con1-1 雷达的定义和类型62Con1-1 雷达的定义和类型63Con1-1 雷达的定义和类型 Radar is an electromagnetic（EM） system f
29、or the detection and location of reflecting objects such as aircraft, ships, spacecraft, vehicles, people and the natural environment. Radar can perform its function at long or short distances and it can operate in darkness, haze, fog, rain, and snow. Its ability to measure distance with high accura
30、cy and in all weather is one of its most important attributes. The range of radars can exceed hundreds of miles and they can be placed on mobile platforms greatly increasing their effectivity.64Con1-1 雷达的定义和类型n按雷达接收回波方式 一次雷达（PSR，Primary Surveillance Radar）：发射一束射频能量，接收由目标反射回来的一小部分能量，主要用于进近和场面。(Non-co
31、operative, 2D position) 二次雷达（SSR，Secondary Surveillance Radar）：发射一组飞机应答机可以识别的特征脉冲，由飞机在约定时间间隔内发射一串应答编码脉冲，主要用于航路。(Cooperative,3D position)65nThe simplest radar system transmits a pulse of high frequency energy and listens for the echo of that pulse.nGiven that EM energy travels at , the time it takes
32、for a pulse to travel to a target and the echo to travel back will tell us the range.R = cTR/2where R = range in metersc = the speed of the EM pulseTR = the round trip transit timesm/103866Con1-2 雷达探测目标的原理Con1-2 雷达探测目标的原理nThe radar dish or antenna transmits pulses of radio waves or microwaves which
33、bounce off any object in their path. nThe object returns a tiny part of the waves energy to the radar dish or antenna which is usually located at the same site as the transmitter.nObviously, we cannot send out another pulse until a time window has passed, in which we expect to see a return echo.67Co
34、n1-2 雷达探测目标的原理68 目标斜距的测量目标斜距的测量(测距测距)2R=ctr 2rctR 式中式中, R为目标到雷达站的单程距离为目标到雷达站的单程距离, 单位为单位为m; tr为电磁波往返为电磁波往返于 目 标 与 雷 达 之 间 的 时 间 间 隔于 目 标 与 雷 达 之 间 的 时 间 间 隔 , 单 位 为单 位 为 s ; c 为 光 速 ，为 光 速 ，c=3108m/s。计算计算1us，1ms雷达探测距离，探测雷达探测距离，探测100NM所需时间。所需时间。Con1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理69发射脉冲回波噪声trtrtt 目标斜距的测量
35、（目标斜距的测量（测距测距）Con1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理7071Con1-2 雷达探测目标的原理目标O 目标角度的测量（目标角度的测量（测角测角）雷达天线波束扫描原理Con1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理72条件条件: （1）电磁波沿直线传播）电磁波沿直线传播 （2）雷达天线具有方向性）雷达天线具有方向性天线方向性天线方向性 天线的方向性可用它的方向性函数或根据方向性函数画出天线的方向性可用它的方向性函数或根据方向性函数画出的方向图表示。的方向图表示。(方位角，俯仰角方位角，俯仰角)max( , )( , )( , )EfE Con
36、1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理74Con1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理75Con1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理76Con1-2 Con1-2 雷达探测目标的原理雷达探测目标的原理Con1-3 Con1-3 雷达基本组成雷达基本组成7778Con1-3 Con1-3 雷达基本组成雷达基本组成79Con1-3 Con1-3 雷达基本组成雷达基本组成80Con1-3 Con1-3 雷达基本组成雷达基本组成81Con1-3 Con1-3 雷达基本组成雷达基本组成Con1-4 雷达方程假设：1，天线各向同性且均匀辐射（s
37、pherical spreading）2，接收发射采用同一部天线P 发射机功率G 天线增益R 探测距离 目标截面积82Con1-4 雷达方程Ae天线有效接收面积Smin最小检测信号功率83Con1-4 雷达方程84Con1-4 雷达方程41min322max41min22max)4(4itirtSGPRSAPR22224344(4 )trtrPAPGPRR Pr：雷达接收功率：雷达接收功率Pt：雷达发射功率：雷达发射功率G：雷达天线的增益：雷达天线的增益：目标的散射截面积：目标的散射截面积Ar = Ae ：接收天线的有效接收面积：接收天线的有效接收面积：所用波长：所用波长24eAAG 42Ae
38、GA 8586Con1-4 雷达方程87Con1-4 雷达方程-RCSRCS是一假想面积，是描述目标在一定入射功率下后向散射功率能力的量，该量以面积单位来描述。面积越大，后向散射能力越强，产生的回波功率也就越大。88Con1-4 雷达方程-RCSCon1-4 雷达方程-RCS89海鸥的形体与燕八哥相近，但海鸥的雷达反射截面却比燕八哥大200倍。蜜蜂的体积小于麻雀，但它的雷达反射截面反而比麻雀大16倍。可见，体积的大小并不是决定隐蔽能力的唯一因素，体形才是决定隐身的关键。普通飞机无论何种姿态，都可以产生雷达回波，隐形飞机的则会长时间无回波，偶尔产生强烈回波（即亮点）Questions ?901
39、What is radar?2 How does it work?3 What is it used for in ATC system?4 Which university and which specialty?5 When and where radar was born?6 Who set up radar network along its coast?Airborne Weather Radar(WXR)Airborne Weather Radar(WXR) Con2: Introduction to WXR Con2: Introduction to WXROutlines Fo
40、r Con21 Aviation weather 2 Introduction purpose description display3 Operating Modes Weather Map Turbulence Predictive windshear4 Structure and Location 5 Latest Evolutions92Con2-1 Aviation weather An airborne radars pulse energy is optimized to detect water. The radiated radar energy reflects best
41、when the bipolar (positive and negative) water molecules are able to align. When water freezes, the water molecules are locked into an ice crystal lattice and are unable to align to reflect radar energy efficiently. (example: microwave)Water (rain) is an excellent radar reflector.Dry snow and ice cr
42、ystals are very poor reflectors of radar energy. Wet hail provides the strongest reflection of radar energy. Dry hail reflects some radar energy simply due to its size. Reflectivity characteristics 93Con2-1 Aviation weather A thunderstorm is composed of three parts：The bottom portion of the storm, b
43、elow the freezing level, is composed entirely of liquid precipitation (i.e., rain) and is the most reflective portion of the storm.The middle portion of a thunderstorm occurs above the freezing level (0oC) and up to the altitude where the outside air temperature drops below 40oC. This section of the
44、 storm is composed of a combination of ice crystals and supercooled water.The top of a thunderstorm is composed entirely of ice crystals and reflects very little radar energy. At temperatures less than 40oC, liquid water no longer exists and only ice crystals are present.Thunderstorm/rain94Con2-1 Av
45、iation weather 湍流，也称为紊流，乱流，是指发生在一定空域中的急速且多变的运动气流。湍流区域中的不同位置，气流速度速度和方向方向的变化相当剧烈。湍流是根据区域中微粒的速度偏差速度偏差来定义的，它与微粒的绝对速度无关。湍流报警门限为5m/s(18km/h)Turbulence95Con2-1 Aviation weather Black represents zero to minimal reflectivity. Green represents light reflectivity. Yellow represents moderate reflectivity. Red r
46、epresents heavy to extreme reflectivity. Magenta indicates turbulence.A normal thunderstorm is circular or oval in shape. Variations from this normal shape are indicative of a shear condition within the thunderstorm and can serve as clues to hazardous weather.96Con2-1 Aviation weather nWX (weather)
47、mode: The four colors displayed represent different storm intensities. nWX+T (Weather Plus Turbulence) Mode: It enables display of weather targets with turbulence information97Con2-1 Aviation weather nWind shear is the meteorologists way of describing a rapid change in either wind speed or wind dire
48、ction over a short period of time or distance. nWindshear occurs in all directions, but for convenience, it is measured along vertical and horizontal axis, thus becoming vertical and horizontal windshear.nThe rapid change in wind speed and/or direction poses a very real threat to airplanes during ta
49、ke-off and landing.nWind shear is caused by downburst. A downburst（下击暴流） is a strong downdraft which causes damaging winds on or near the ground.nThe term microburst and marcoburst describe the size of the downburst(4km). Microburst is more important than marcoburst to aviation safety, it can cause
50、damaging winds as high as 75 m/s(168 mph,270 km/h). nThe key difference between downburst and tornado is in two words - IN and OUT98Con2-1 Aviation weather (a)低空风切变对飞机运行安全的影响示意图低空风切变对飞机运行安全的影响示意图(b) 雷暴引发的风切变雷暴引发的风切变99Con2-1 Aviation weather nMicrobursts combine two distinct threats to aviation safet
