5近地警告系统

1、近地警告系统近地警告系统（GPWS）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电子信息工程学院二次雷达（SSR）CFITCFIT（可控飞行撞地）v CFIT: Controlled flight into terrain. CFIT: Controlled flight into terrain. 为民航两大为民航两大主要航空事故之一（主要航空事故之一（ALAALA： Approach and Landing），），为一架飞机由机师正常控制，但因为一些失误而撞上地为一架飞机由机师正常控制，但因为一些失误而撞上地面、阻碍物或水面坠毁。面、阻碍物或水面坠毁。v 根据国际民航组织的统计

2、，可控飞行撞地是加装GPWS之前商用喷气飞机机体损毁事故和人员死亡事故的元凶。1974年，FAA开始对在美国空域飞行的航班上的GPWS进行强制安装要求（Honeywell），此后CFIT事故急剧减少。1985年后，CFIT事故每年仅发生1到2次，而强制要求安装前每年发生7到8次。目前，全球几乎所有的商用喷气飞机均装备GPWS。 v GPWS is a system developed to help prevent CFIT GPWS is a system developed to help prevent CFIT accidents.accidents.电子信息工程学院二次雷达（SSR）

3、GPWSGPWSv 定义：地面迫近警告系统（定义：地面迫近警告系统（GPWS, GPWS, Ground Proximity Warning Ground Proximity Warning SystemSystem），又称近地警告系统，），又称近地警告系统，是防止飞机因为离地过近而发生是防止飞机因为离地过近而发生事故的系统，与事故的系统，与TCASTCAS搭配成为保搭配成为保护飞航安全的两大防线。护飞航安全的两大防线。v 原理：原理：GPWSGPWS在起飞开始到降落地在起飞开始到降落地面为止，持续监视面为止，持续监视飞机离地高度飞机离地高度，利用无线电高度表获得离地高度，利用无线电高度表获得

4、离地高度，并且以电脑计算出飞机的并且以电脑计算出飞机的飞行趋飞行趋势势，若有危险时会以视觉与语音，若有危险时会以视觉与语音警告飞行员采取避险措施。警告飞行员采取避险措施。 电子信息工程学院二次雷达（SSR）EGPWSEGPWSv EnhancedEnhanced Ground Proximity Warning Systems (EGPWS), Ground Proximity Warning Systems (EGPWS), also called Terrain Awareness Warning Systems also called Terrain Awareness Warning

5、Systems ( (TAWSTAWS).).v A limitation of GPWS is the fact that with radar A limitation of GPWS is the fact that with radar altimeter information the aircraft is only capable altimeter information the aircraft is only capable of seeing of seeing terrain directly belowterrain directly below. In the ca

6、se of . In the case of rapidly rising terrainrapidly rising terrain it may not react quick it may not react quick enough to issue a warning in time.enough to issue a warning in time.v EGPWS corrects this problem by integrating an EGPWS corrects this problem by integrating an aircraft navigational so

7、urceaircraft navigational source into the system. into the system. GPS GPS positionposition in conjunction with a in conjunction with a terrain databaseterrain database is is used to help predict terrain conflict.used to help predict terrain conflict.v Honeywe11Honeywe11公司在原有公司在原有GPWSGPWS基础上，开发出新型增强

8、型近基础上，开发出新型增强型近地警告计算机系统，该系统不仅增加了警告时间，还提供地警告计算机系统，该系统不仅增加了警告时间，还提供非常直观的地形显示，方便机组发现潜在的危险地形状况，非常直观的地形显示，方便机组发现潜在的危险地形状况，避免避免 CFITCFIT事故的发生。事故的发生。电子信息工程学院二次雷达（SSR）HOW IT WORKSHOW IT WORKSv GPWSGPWS是当航机在异常接近地障的状况下是当航机在异常接近地障的状况下, ,使用语音使用语音, ,灯号以及在萤幕显灯号以及在萤幕显示警告文字来警告飞行员示警告文字来警告飞行员. .这套系统只有在这套系统只有在RA(Radio

9、 Altitude)RA(Radio Altitude)24502450尺以下才会作用启动尺以下才会作用启动. . v The heart of the GPWS is a computer processor which The heart of the GPWS is a computer processor which which can analyze the data from:which can analyze the data from: Radar altimeterRadar altimeter（雷达高度计）（雷达高度计） Air data computerAir data

10、computer（大气数据计算机）（大气数据计算机） UHF Nav receiverUHF Nav receiver（Ultra-high frequencyUltra-high frequency导航接收机）导航接收机） Gear and flap indicating systemGear and flap indicating system（起落架和襟翼指示系统）（起落架和襟翼指示系统） Roll attitude input sensorRoll attitude input sensor（滚动姿态输入传感器）（滚动姿态输入传感器）v The computer analyzes a

11、number of parameters including The computer analyzes a number of parameters including aircraft configuration, speed, proximity to terrain, and aircraft configuration, speed, proximity to terrain, and descent rate in order to issue appropriate warnings.descent rate in order to issue appropriate warni

12、ngs.电子信息工程学院二次雷达（SSR）Enhanced GPWS Features In addition to retaining current GPWS alerting functions, the EGPWS offers two new major features : Look-ahead terrain alerting. Terrain display. 电子信息工程学院二次雷达（SSR）电子信息工程学院二次雷达（SSR）EGPWS: Look-ahead Terrain AlertingThe EGPWS provides caution-andwarning-leve

13、l alerts to the flight crew about potential terrain conflicts earlier than basic GPWS.The alerts are based primarily on the airplane position and barometric altitude information passed to the EGPWS. Either a flight management system (FMS) or global positioning system (GPS) can provide airplane posit

14、ion (latitude and longitude) to the EGPWS. The look-ahead distance varies mainly with ground speed, The look-ahead caution alert is provided approximately 40 to 60 seconds before a potential terrain conflict, and the look-ahead warning alert is provided approximately 20 to 30 seconds before such a c

15、onflict.The altitude offset is normally 700 feet (213m) below the airplane. The purpose of the offset is to provide terrain alerting when the airplane has less than the normal terrain clearance. 电子信息工程学院二次雷达（SSR）电子信息工程学院二次雷达（SSR）EGPWS: Terrain DisplayThe EGPWS terrain display is designed to increase

16、 flight crew awareness of the surrounding terrain and to potentially avoid terrain conflicts entirely. The terrain display can be selected manually by the flight crew or displayed automatically when a look-ahead caution or warning alert activates. The terrain is displayed on the Electronic Horizonta

17、l Situation Indicator (EHSI) or navigation display (ND), or on a dedicated weather radar display in flight decks without map displays. The terrain is shown on the display in dotted patterns of red, amber, and green, with the colors indicating the height of the terrain relative to the current airplan

18、e altitude .-dotted red: 2,000 feet (610m) above the airplane altitude -dotted amber: from 500 feet (152m) below the current airplane altitude to 2,000 feet (610m) above-dotted green: 500 feet (152m) below电子信息工程学院二次雷达（SSR）电子信息工程学院二次雷达（SSR）电子信息工程学院二次雷达（SSR）电子信息工程学院二次雷达（SSR）To reduce clutter on the di

19、splay, any terrain more than 2,000 feet (610m) below the airplane is not displayed, and instead remains the background color of black. Because the terrain colors are displayed relative to the current airplane altitude, the colors will change as the airplane climbs or descends. In those areas of the

20、world for which the EGPWS terrain database does not yet contain terrain data, a dotted magenta pattern will show on the display.EGPWS: Terrain Display电子信息工程学院二次雷达（SSR）电子信息工程学院二次雷达（SSR）Reference altitudeReference altitude电子信息工程学院二次雷达（SSR）Peak displayPeak displayThe following image illustrates the Pea

21、ks display at a high relative altitude.The following image illustrates the Peaks display at a low relative altitude.电子信息工程学院二次雷达（SSR）如何发出警告如何发出警告v EGPWS EGPWS可以向机组提供可以向机组提供警戒警戒或或警告警告信息。信息。当前飞行状况导致当前飞行状况导致EGPWSEGPWS警戒或警告启警戒或警告启动时，无论机组是否选择，地形图将动时，无论机组是否选择，地形图将强强制性的自动显示制性的自动显示在飞行仪表上。在飞行仪表上。v 在在EGPWSEGP

22、WS中，计算机沿着飞机的中，计算机沿着飞机的预定航预定航迹连续搜索地形数据库迹连续搜索地形数据库，这样可使系统，这样可使系统具有虚拟的前视能力。若飞机正在下降，具有虚拟的前视能力。若飞机正在下降，计算机会沿下滑航迹进行搜索；若飞机计算机会沿下滑航迹进行搜索；若飞机正在转弯，则沿转弯航迹搜索。正在转弯，则沿转弯航迹搜索。v 如果如果EGPWSEGPWS认为飞机的航迹在某处与地认为飞机的航迹在某处与地形太近，它会形太近，它会提前一分钟提前一分钟以上发出以上发出音频音频和和视频视频告警信号。告警信号。v 当当EGPWSEGPWS系统发出告警时，在飞行仪表系统发出告警时，在飞行仪表上将用上将用彩色固定

23、方块彩色固定方块来加以强调，表示来加以强调，表示会引发危险的地形，同时还伴随有相应会引发危险的地形，同时还伴随有相应的音响告警。的音响告警。v 固定的固定的红色方块红色方块表示地形处在表示地形处在3030秒的飞秒的飞行时间范围内，要求机组立即执行避开行时间范围内，要求机组立即执行避开地形机动程序；而固定的地形机动程序；而固定的黄色方块黄色方块则表则表示地形处在大约示地形处在大约3030到到6060秒的飞行时间范秒的飞行时间范围内，要求机组立即检查飞行轨迹按需围内，要求机组立即检查飞行轨迹按需修正，并执行相应地形机动程序。修正，并执行相应地形机动程序。 电子信息工程学院二次雷达（SSR）Oper

24、ation modeOperation modev Mode 1: Excessive Descent Rate(过度的下降速率)。（SINK RATE PULL UP）v Mode 2: Excessive Closure to Terrain(过度的地障接近率)。（TERRAIN.TERRAIN PULL UP）v Mode 3: Altitude Loss After Takeoff(在航机起飞（Takeoff）或重飞（Go around）爬升时航机高度值过度下降(Altitude loss)。（DONT SINK）v Mode 4: Unsafe Terrain Clearance(与

25、地障的间距不足)（未放下起落架或襟翼小于30度等）。（TOO LOW - TERRAIN TOO LOW - GEAR TOO LOW - FLAPS）v Mode 5: Excessive Deviation Below Glide slope(仪器降落时与下滑道（Glide slope）的误差过大)。(GLIDE SLOPE)v Mode 6: Advisory Callouts(正常下降时的提醒)。(“Bank Angle” “Five Hundred” “Minimums”)v Mode 7: Windshear Alerting(当飞机遭受风切变警讯)。(“Caution, Wind

26、shear” “Windshear, Windshear, Windshear”)电子信息工程学院二次雷达（SSR）Operation modeOperation modev Mode 1: Excessive Descent Rate(过度的下降速率过度的下降速率)电子信息工程学院二次雷达（SSR）Operation modeOperation modev Mode 2: Excessive Closure to Terrain(过度的地障接近率过度的地障接近率)电子信息工程学院二次雷达（SSR）Operation modeOperation modev Mode 3: Altitude L

27、oss After Takeoff(在航机起飞（在航机起飞（Takeoff）或重飞（或重飞（Go around）爬升时航机高度值过度下降）爬升时航机高度值过度下降(Altitude loss)电子信息工程学院二次雷达（SSR）Operation modeOperation modev Mode 4: Unsafe Terrain Clearance(与地障的间距不足与地障的间距不足)（未放下起落架或襟翼小于（未放下起落架或襟翼小于30度等）度等）电子信息工程学院二次雷达（SSR）Operation modeOperation modev Mode 5: Excessive Deviation

28、Below Glide slope(仪器降落仪器降落时与下滑道（时与下滑道（Glide slope）的误差过大）的误差过大)电子信息工程学院二次雷达（SSR）Operation modeOperation modev Mode 6: Advisory Callouts(正常下降时的提醒正常下降时的提醒)callouts would be made by the pilot not flying (PNF).电子信息工程学院二次雷达（SSR）Terrain Clearance Floor(TCF)Terrain Clearance Floor(TCF)v The The Terrain Clea

29、rance FloorTerrain Clearance Floor ( (地形净空基底或地形净空平面地形净空基底或地形净空平面 ) ) function (enabled with TAD) function (enabled with TAD) enhances the basic GPWS enhances the basic GPWS Modes by alerting the pilot Modes by alerting the pilot of descent below a defined of descent below a defined Terrain Clearance

30、 Floor Terrain Clearance Floor regardless of the aircraft regardless of the aircraft configuration. configuration. v The TCF alert is a The TCF alert is a functionfunction of the aircrafts Radio of the aircrafts Radio Altitude and distance Altitude and distance relative to the centre of relative to

31、the centre of the nearest or destination the nearest or destination runwayrunway included in the included in the database. database. 电子信息工程学院二次雷达（SSR）TCF envelope电子信息工程学院二次雷达（SSR）Runway Field Clearance Floor(RFCF)Runway Field Clearance Floor(RFCF)v 跑道高于周围地形的机场。v A RFCF RFCF feature is similar to the

32、 TCF feature except that RFCF is based on the current aircraft position and height above the destination runway, using Geometric Altitude (in lieu of Radio Altitude). v This provides improved protection at locations where the runway is significantly higher than the surrounding terrain as illustrated below.v TCF and RFCF alerts result in ill