1、空中防撞系統(tǒng)TCAS,中國民航大學 電子信息工程學院,Contents,Introduction to TCAS Function of TCAS TCAS Aler Area TCAS Information Principle of TCAS TCAS Components TCAS Interface TCAS Signal formats TCAS Display,TCAS概述,TCAS I能夠偵測上下7000至10000呎，前后15至40海里，發(fā)現(xiàn)有航機接近時，會提前40秒警告飛行員對方飛機的高度和位置。 第二代空中防撞系統(tǒng)（TCAS II），是目前最被廣泛使用的，會用聲音及顯示警告

2、飛行員，稱為Resolution Advisory （RA），并且會用語音指示避撞的動作，例如：“Climb！Climb！Climb！”“Descend！Descend！Descend！”。別架飛機若有裝TCAS，也會有相反的警告發(fā)出來。 第三代空中防撞系統(tǒng)（TCAS III），除了有上下避撞措施之外，還增加左右避撞能力。 Honeywell公司是唯一一家生產(chǎn)所有類型TCAS的制造商，超過一半的TCAS產(chǎn)品都是出自該公司。 ICAO: the carriage of ACAS II has been mandatory worldwide from 1-1-2005 for all civil

3、ian turbine-engined aircraft carrying more than 19 passengers or with the maximum take-off mass more than 5700 kg,TCAS Function,TCAS Information,根據(jù)入侵機的相對距離和方位，以及威脅等級在EHSI 或EADI上顯示視覺信息： Others （其它）：相對高度大于1200英尺、小于2700英尺，或距離在6海里以上。 Proximity （接近）：相對高度等于或小于1200英尺，且距離在6海里以內(nèi)。 Traffic Advisory （交通咨詢）：系統(tǒng)判明

4、的與本機存在潛在危險接近的飛機，TCAS會提前一定時間（2048秒）發(fā)出交通咨詢。音頻 Resolution Advisory （決斷咨詢）：在對已判明為交通咨詢的飛機連續(xù)監(jiān)視約15秒后，如果該機與本機危險接近的狀況仍然存在，則TCAS會發(fā)出解脫咨詢。,TCAS Information,TCAS Information,TCAS Information,TCAS Information,TCAS Information,TCAS Information,TCAS Information,語音信息 含義 TRAFFIC, TRAFFIC 交通，交通 CLIMB, CLIMB 爬升，爬升 DESC

5、END ,DESCEND 下降，下降 INCREASE CLIMB INCREASE CLIMB 增大爬升，增大爬升 INCREASE DESCEND INCREASE DESCEND 增大下降，增大下降 CLIMB,CROSSING CLIMB CLIMB,CROSSING CLIMB 爬升，穿越爬升爬升，穿越爬升 DESCEND ,CROSSING DESCEND 下降，穿越下降 CLIMB, CLIMB NOW CLIMB, CLIMB NOW 爬升，現(xiàn)在爬升爬升，現(xiàn)在爬升 DESCEND, DESCEND NOW DESCEND , DESCEND NOW 下降，現(xiàn)在下降下降，現(xiàn)在下降

6、 ADJUST VERTICAL SPEED, ADJUST 調(diào)節(jié)垂直速度，調(diào)節(jié) MORNITOR VERTICAL SPEED 監(jiān)視垂直速度 MAINTAIN VERTICAL SPEED, MAINTAIN 保持垂直速度，保持 MAINTAIN VERTICAL SPEEDCROSSING MAINTAIN 保持垂直速度保持穿越 CLEAR OF CONFLICT 沖突解除 TCAS TEST TCAS 自檢 TCAS TEST OK TCAS自檢通過 TCAS TEST FAIL TCAS自檢失敗,TCAS Information,TCAS Alert Area,TCAS Alert A

7、rea,TCAS Principle,TCAS Principle,TCAS Principle,TCAS Principle,TCAS Principle,TCAS Principle,Horizontal test: time to reach the Closest Point of Approach (CPA)(or DMOD distance if the closure rate is low) Vertical test:time to reach co-altitude (or ZTHR if the aircraft are steady) The TA/RA thresho

8、ld values increase with the altitude The bearing is not taken into account (only used for the display) The TA or RA is issued depending upon the relevant thresholds RA sense selection: objective of safe vertical distance ALIM, co-ordination If the intruder does not transmit its altitude, there will

9、be no RA,TCAS Principle,ILLUSTRATION OF THE HORIZONTAL TEST,35 seconds,Intruder,TCAS,The collision avoidance criterion is a generally a time parameter,TCAS Principle,LOW CLOSURE RATE,Air speed,Closure rate,Air speed,Intruder,TCAS,The closure rate can be low even if the air speeds are high.,TCAS Prin

10、ciple,VERTICAL TEST,35 seconds,Intruder,TCAS,The time remaining to co-altitude is compared to triggering time threshold (here 35 seconds),In case of steady aircraft, current vertical distance is compared to vertical threshold ZTHR (e.g. 800ft),TCAS Principle,ALERTS: TRAFFIC ADVISORY,Thresholds: hori

11、zontal:20 to 48 s (or DMOD = 0.3 to 1.3 NM) vertical:20 to 48 s (or ZTHR = 850 or 1,200 ft) Aural annunciation: Traffic, traffic” Intruder: solid amber circle Helps to the visual acquisition of the intruder Prepares the crew for a possible RA No maneuver should be made if there is no visual acquisit

12、ion No associated phraseology,TCAS Principle,ALERTS: RESOLUTION ADVISORY,Thresholds: horizontal:15 to 35 s (or DMOD = 0.2 to 1.1 NM) vertical:15 to 35 s (or ZTHR = 600 to 800 ft) Aural annunciations: climb, descend, increase climb, increase descent, monitor vertical speed, etc Display of a range of

13、vertical speeds or pitches to avoid Objective: a safe vertical distance ALIM varying from 300 to 700 ft An RA takes into account all existing threats The RA intensity is checked and revised, if necessary, every second,TCAS Principle,THRESHOLD VALUES FOR TCAS II V7.0,* vtt: vertical threshold test (p

14、rocessing of 1,000-ft level off geometries),TCAS Principle,RA SENSE SELECTION,The downward sense will achieve ALIM, the upward sense will not. The downward option is therefore selected,TCAS Principle,RA WITHOUT ALTITUDE CROSSING,Both downward and upward senses will achieve ALIM. The upward sense is

15、selected because it prevents the TCAS aircraft from crossing through the intruders altitude,TCAS Principle,RA WITH ALTITUDE CROSSING,The upward sense is not sufficient to achieve ALIM. The downward sense (Crossing descent here) RA is choosen, however it is really issued only when the current vertica

16、l separation is less than 600 ft (intruder steady) or 850 ft (intruder evoluting toward the own aircraft). All these cases are rare.,TCAS Principle,INCREASE RATE RA,The threat increase its descent rate towards TCAS aircraft after the initial “descent” RA is issued,TCAS Principle,RA REVERSAL,TCAS Pri

17、nciple,MODE C TARGET ON-THE-GROUND DETERMINATION,TCAS Principle,POSSIBLE INITIAL RAs,TCAS Principle,TCAS System Architecture,TCAS System Architecture,TCAS System Architecture,S模式應答機 TCAS計算機 天線 顯示器 控制板,TCAS System Architecture,TCAS的方向性天線,TCAS System Architecture,TCAS天線的方向性,TCAS System Architecture,TC

18、AS 計算機,TCAS System Architecture,TCAS 計算機的基本功用,監(jiān)視鄰近空域中的飛機； 獲取所跟蹤飛機的數(shù)據(jù)； 進行威脅評估計算； 產(chǎn)生交通咨詢或決斷咨詢等。,TCAS System Architecture,ATC/TCAS控制面板,TCAS System Architecture,控制面板,TCAS System Architecture,TCAS System Architecture,控制面板,TCAS Interface,TCAS Interface,TCAS Interface,TCAS計算機通過ARINC數(shù)據(jù)總線與S模式應答機實現(xiàn)數(shù)據(jù)交換。 S模式應答

19、機通過一條ARINC 429數(shù)據(jù)總線，將有關信息輸往TCAS計算機；TCAS計算機則利用另一條ARINC 429數(shù)據(jù)總線，將有關信息輸往S模式應答機。 S模式應答機輸送給TCAS計算機的信息中，包括由大氣數(shù)據(jù)計算機系統(tǒng)獲得的高度信息、來自控制面板的各種信息等。 TCAS計算機與控制面板的信號交連 XPNDR/TCAS控制面板對TCAS計算機的模式等控制信息，是通過S模式應答機再輸送給TCAS計算機的。 飛機的24位地址碼由應答機上的程序銷釘輸入應答機。,TCAS Interface,EFIS控制面板對TCAS顯示的控制 （1）EHSI的工作模式（NAV、VOR/ILS、MAP ） （2）TFC

20、按鈕 （3）距離選擇（小距離：5、10、20） TCAS與EFIS顯示器之間的信號交連 TCAS輸出的視覺信息，輸往兩部EFIS的符號發(fā)生器，然后再分別輸往EHSI和EADI顯示。 此外，EHSI和EADI顯示器必須將其狀態(tài)信息輸送給TCAS計算機，以便TCAS計算機產(chǎn)生交通咨詢和解脫咨詢等信息。,TCAS Interface,無線電高度信息輸入 TCAS在避撞計算中必須利用無線電高度信息。兩部無線電高度表輸出的數(shù)字式高度信息，通過ARINC 429數(shù)據(jù)總線輸送給TCAS計算機。 航向信息輸入 航向信息是確定本機飛行軌跡的必要參數(shù)。數(shù)字式航向信息通過ARINC 429數(shù)據(jù)總線輸送給TCAS計算

21、機。 大氣數(shù)據(jù)計算機信息輸入 大氣數(shù)據(jù)計算機產(chǎn)生的有關本機的高度、速度、升降速度等信息，通過ARINC 429數(shù)據(jù)總線輸入TCAS計算機。 L波段設備的互抑制 飛機上的兩部應答機、兩部測距機和TCAS均工作于L波段。為避免相互干擾，同一時刻只應有一部處于發(fā)射狀態(tài)。在五部L波段設備中的一部開始發(fā)射之前，產(chǎn)生一個寬度為28s的外抑制波門加到其它L波段設備，以避免其它L波段設備進入發(fā)射狀態(tài)，并保護其接收設備。 來自近地警告系統(tǒng)的抑制信號 近地警告系統(tǒng)產(chǎn)生的“低于下滑道”、“拉起”和“風切變”警告信息的優(yōu)先權(quán)高于TCAS的咨詢信息，所以，在近地警告系統(tǒng)發(fā)出上述三種警告信號時，會抑制TCAS輸出交通咨詢

22、和解脫咨詢。,TCAS Signal Format,Mode C only interrogation,TCAS Signal Format,Whisper-shout interrogation,Remark：用來防止同步串擾的一種方案。,TCAS Signal Format,Whisper-shout interrogation,TCAS Signal Format,Whisper-shout interrogation,TCAS Signal Format,Mode S interrogation,TCAS Signal Format,Mode S interrogation,數(shù)據(jù)脈沖P

23、6包含67個數(shù)據(jù)區(qū)。每個數(shù)據(jù)區(qū)的位數(shù)示于圖中；各數(shù)據(jù)區(qū)的內(nèi)容如下： 第一區(qū)為數(shù)據(jù)子標號，5位，用于表明本詢問信號的格式； AP：地址/奇偶校驗；AQ：特殊詢問；DI：識別符；MA：公共A信息；MU：公共U信息；PC：協(xié)議；RL：應答長度；RR：應答請求；SD：特殊符。,TCAS Signal Format,Mode S interrogation,數(shù)據(jù)脈沖P6包含67個數(shù)據(jù)區(qū)。第一區(qū)為數(shù)據(jù)子標號，5位，用于表明本應答信號的格式；AA：通告的地址；AC：高度碼；AP：地址/奇偶校驗；CA：應答機的能力；DR：下行鏈請求；FS：飛行狀態(tài)；ID：識別碼；MB：公共B信息；MV：公共V信息；PI：奇偶/詢問識別；RI：空-空應答信息；SL靈