机载气象雷达系统.ppt

CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem 机载气象雷达系统 AirborneWeatherRadarSystem CivilAviationFlightUniversityofChina Theweatherradar WXR systemisdesignedtoprovidetheflightcrewwithatopographicmaptypeofdisplayofmoistureladenweatherformationsinordertoavoidheavyprecipitationorturbulence Asasecondaryfunction theweatherradarantennacanbetilteddownwardtoprovideadisplayofmajorterrainfeaturessuchasrivers coastlines majormountainpeaks andcities AirborneWeatherRadarSystem CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem WeatherradarsystemsoperateintheX band Maximumrangeofmodernradarsisabout300nm Detectedweatherconditionsandgroundmappinginformationcanbedisplayedinthecockpit Theantennaisnormallystabilizedusingattitudesignalsfromoneoftheverticalgyros orinertialreferences toavoidclutterfromground returnsduringturns CivilAviationFlightUniversityofChina Aweatherradarsystemconsistsofareceiver transmitter R T anantenna acontrolpanel andindicators Thecontrolpanelallowsthecrewtocontrolpowerapplicationandtoselectvariousmodesofweatherradaroperation Usingthecontrolpanelselections thereceiver transmittergeneratesandtransmitshighenergyradiofrequency RF pulses TheseRFpulsesaresenttotheantenna andradiated AirborneWeatherRadarSystem BasicPrinciples CivilAviationFlightUniversityofChina Theantennaoscillatestosweepthepencilshapedradarbeamabout90 eithersideofthenose andcanbetiltedupanddowntoabout 15 MoistureLadencloudsortheterrainwillreflectsomeoftheseRFpulsesbacktotheantenna Thisreflectedenergyisreceivedbytheantenna processedbytheR Tunitanddisplayedontheindicators AirborneWeatherRadarSystem BasicPrinciples CivilAviationFlightUniversityofChina Whattargetwillreflecttheradar spulsesandthusbedisplayedontheindicator Onlyprecipitation orobjectsmoredensethanwatersuchasearthorsolidstructures willbedetectedbyX bandweatherradar Thereforeweatherradardoesnotdetectclouds thunderstormsorturbulencedirectly Instead itdetectsprecipitationwhichmaybeassociatedwithdangerousthunderstormsandturbulence Thebestradarreflectorsareraindropsandwethail Generally ice drysnow anddryhailhavelowreflectivelevelsandoftenwillnotbedisplayedbytheradar AirborneWeatherRadarSystem BasicPrinciples CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem BasicPrinciples CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem BasicPrinciples Figure5 1 CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem BasicPrinciples Turbulencemaybedividedintotwobasictypes clear airturbulence andturbulenceassociatedwiththunderstormsandprecipitation Theweatherradarisnotpossibletodetectclearairturbulence Theradarreturnsareprocessedbythereceiver transmitterandshownontheEHSIincolorasweatherormapinformation Areasofheaviestrainfallappearinred moderaterainfallinyellowandlightrainfallingreen Turbulenceinformationisshownusingmagenta CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem BasicPrinciples Figure5 2 HeaviestRainfall ModerateRainfall LightRainfall NoRainfall TurbulenceArea TurbulenceArea CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem ControlPanel WeatherRadarControlPanel CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem GAINThesystemgainmaybeadjustedintheWX WX T orMAPmodesbytheGAINcontrol ThecontrolhastendetentedpositionsincludingtheCALposition wherethesystemgainisautomaticallycalibrated CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem TILTTheantennatiltpositioniscontrolledbytheTILTcontrol Thetiltrangeisfrom15 downto15 up CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem WXPressingtheWXpushbuttonswitchestheR Tunittotheweathermode andweatherdatawillbedisplayedontheEHSI CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem WX TPressingtheWX TpushbuttonswitchestheR Tunittotheweatherplusturbulencemode andturbulenceaswellasweatherdatawillbedisplayedontheEHSI Turbulencewith40nmorlessisdisplayed CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem MAPPressingtheMAPpushbuttonswitchestheR Tunittothegroundmappingmode andterrainfeatureswillbedisplayedontheEHSI CivilAviationFlightUniversityofChina Figure5 4 AirborneWeatherRadarSystem TESTThetestmodeisselectedbypressingtheTESTpushbutton IntheTESTmode atestpatternandthesystemstatusmessageswillbedisplayedontheEHSI CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem IDNTThispushbuttonactivatesgroundcluttersuppressiontoreducegroundclutterinWXandWX Tmodes CivilAviationFlightUniversityofChina Figure5 3 AirborneWeatherRadarSystem STABStabilizationisengagedbypressingtheSTABpushbutton Withstabilizationselected theantennastabilizationisprovidedbytheIRSthroughtheR Tunit CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem Display EHSIPresentation Onmoderncommercialairplanes theweatherradardataisusuallyshownontheEHSI TheEHSIsshowtheweatherradardatainExpandedNAV ExpandedVOR ILS MAPandCenterMAPmodes TheWXRswitchontheEFIScontrolpanelisusedtoturnontheweatherradarsystemandtoturnonweatherradardisplay CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem Figure5 5 TurbulenceArea CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem Theweatherormapdisplayiscolorcoded Targetsprovidingthemostintensereturnsareshownusingthecolorred Targetswithlessintensityareshownusingthecolorsyellow greenandblack Turbulenceinformationisshownusingmagenta CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem OperationIn Flight EarlyDetectionofEn routeWeatherTosettheantennatilttooptimizetheradar sabilitytoquicklyidentifysignificantweather followthesesteps SelecttheWXmodeofoperation AdjustBrightnesscontrolasdesired Selectthe40or80nmrange Adjusttheantennatiltcontroldownuntiltheentiredisplayisfilledwithgroundreturns Slowlyworktheantennatiltupsothatgroundreturnsarepaintedonorabouttheouteronethirdoftheindicatorarea CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem OperationIn Flight EarlyDetectionofEn routeWeatherWatchthestrongestreturnsseenonthedisplay If astheyareapproached theybecomeweakerandfadeoutafterbackinsidethenearlimitofthegeneralgroundreturnpattern theyareprobablygroundreturnsorinsignificantweather Iftheycontinuestrongafterworkingdownintothelowerhalfoftheindicator youareapproachingahazardousstormorstormsandshoulddeviateimmediately Examinetheareabehindstrongtargets Ifradarshadowsaredetectedyouareapproachingahazardousstormorstormsandshoulddeviateimmediately regardlessoftheaircraft saltitude Ifweatherisbeingdetected movetheantennatiltcontrolupanddowninsmallincrementsuntilthereturnobjectisoptimized CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem OperationIn Flight BlindAlleyA BlindAlley or BoxCanyon situationcanbeverydangerouswhenviewingtheshortranges Periodicallyswitchtolonger rangedisplaystoobservedistantconditions AsshowninFigure5 6 theshort rangereturnsshowanobviouscorridorbetweentwoareasofheavyrainfallbutthelong rangesettingshowsalargerareaofheavyrainfall Figure5 6 CivilAviationFlightUniversityofChina AirborneWeatherRadarSystem OperationIn Flight PathPlanningConsiderationsAvoidcellcontainingmagentaandredareasbyatleast20nauticalmiles Donotdeviatedownwindunlessabsolutenecessary Yourchancesofencounteringsevereturbulenceanddamaginghailaregreatlyreducedbyselectingtheupwindsideofthestorm Iflookingforacorridor remembercorridorsbetweentwocellscontainingmagentaand orredareasshouldbeatleast40nauticalmileswidefromtheouterfringesoftheradarecho