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ID:36532877
大小:248.33 KB
页数:10页
时间:2019-05-11
《TACTICALAIRNAVIGATION(TACAN)我TCTCLRNV我GTION(TCN)》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、CHAPTER2TACTICALAIRNAVIGATION(TACAN)INTRODUCTION(2)usethebearinganddistancefromaspecificbeacontofixhisorhergeographiclocation.BeforewebegindiscussingTACAN,youneedtorecallthedefinitionofthepolar-coordinatesystem.TACANPRINCIPLESThepolar-coordinatesystemisa
2、geometricsystemusedtolocatepointsonaplane.Inelectronics,itisThedistancemeasuringconceptusedinTACANusuallyusedforplottingantennadirectionalpatterns.equipmentisanoutgrowthofradar-rangingtechniques.Radar-rangingdeterminesdistancebyTACANisapolar-coordinatety
3、peradioair-measuringtheround-triptraveltimeofpulsedrfnavigationsystemthatprovidesanaircrewwithenergy.Thereturnsignal(echo)oftheradiateddistanceinformation,fromdistancemeasuringenergydependsonthenaturalreflectionoftheradioequipment(DME),andbearing(azimuth
4、)waves.However,TACANbeacon-transpondersinformation.Thisinformation,asshowninfigure2-generateartificialrepliesinsteadofdependingon1,isusuallyprovidedbytwometers.Onemeternaturalreflection.indicates,innauticalmiles,thedistanceoftheaircraftfromthesurfacebeac
5、on.TheothermeterindicatesNowlookatfigure2-2.Theairborneequipmentthedirectionofflight,indegrees-of-bearing,tothegeneratestimedinterrogationpulsepairsthatthegeographiclocationofthesurfacebeacon.ByusingsurfaceTACANsystemreceivesanddecodes.AftertheTACANequip
6、mentinstalledintheaircraftanda50-µsecdelay,thetransponderrespondswithaTACANgroundequipmentinstalledaboardareply.TheairborneDMEthenconvertstheround-particularsurfaceshiporshorestation,apilotcantriptimetodistancefromtheTACANfacility.Theobtainbearingtoanddi
7、stancefromthatlocation.Hefrequencyandidentificationcodeprovidetheorshecantheneither:geographiclocationofthetransmittingbeacon.(1)flydirectlytothatparticularlocation,orTACANPULSEPAIRSTACANtranspondersusetwin-pulsedecoderstopassonlythosepulsepairswiththepr
8、operspacing.Thepurposeofthistwin-pulsetechniqueistoincreasetheaveragepowerradiatedandtoreducethepossibilityoffalsesignalinterference.Afterthereceiverdecodesaninterrogation,theencodergeneratesthenecessarypulsepairrequiredfo
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