Raymarine A65 - Page 157

•Thetargetechoisweak.Thetargetisveryclosetoland,buoys
orotherlargetargets.
•Thetargetoryourownvesselismakingrapidmanoeuvres.
•Choppyseastateconditionsexistandthetargetisburiedin
excessiveseaclutterorindeepswells.
•Choppyseastateconditionsexistyieldingpoorstability;own
vessel’sheadingdataisveryunstable.
•Inadequateheadingdata.
Symptomsofsuchconditionsinclude:
•targetacquisitionisdifcultandtheMARPAvectorsareunstable;
•thesymbolwandersawayfromthetarget,locks-ontoanother
target,orchangestoalostsymboltarget.
Inthesecircumstances,targetacquisitionandtrackingmayneedto
bere-initiatedandinsomecasesmightbeimpossibletomaintain.
Betterqualityheadingdatamightimproveperformanceinthese
circumstances.
HowaMARPAriskisassessed
Eachtargetismonitoredtoascertainwhetheritwillbewithina
certaindistancefromyourvesselwithinacertaintime.Ifso,the
targetisdesignatedasdangerous,andanaudiblewarningis
soundedandawarningdisplayed.Thetargetsymbolchangesto
thedangeroustargetsymbolandashestoindicatethatitisa
dangeroustarget.Acknowledgingthealarmwillremovethewarning.
Ifatargetislost,eitherbecausetheMARPAsoftwarehaslost
contactwithit,orbecauseithasmovedoutofrange,anaudible
alarmissoundedandanon-screenwarningappears.Theon-screen
symbolwillchangetothetargetlostsymbol.Acknowledgingthe
warningwillsilencethealarmandremovetheon-screenwarning
andthetargetlostsymbol.
EffectiverangeforMARPAtargets
MARPAtargetacquisitionisonlyavailableatradarrangescalesof
upto12nm,althoughtrackingcontinuesatallranges.
Ifyouchangetoasmallerrangescale,targetsmaybebeyondthe
rangeofyourradarscannerandwillbelost.Insuchcases,an
on-screenwarningindicatesthatthetargetisoff-screen.
MARPAcontextmenu
TheMARPAfunctionincludesacontextmenuwhichprovides
positionaldataandmenuitems.
Thecontextmenuprovidesthefollowingtargetinformation:
•CPA
•TCPA
•COG
•SOG
Thecontextmenualsoprovidethefollowingmenuitems:
•Canceltarget
•CPAGraphic
•MARPAData
•Slewthermalcamera(Onlyavailablewhenthermalcamerais
connectedandoperating.)
Accessingthecontextmenu
Youcanaccessthecontextmenubyfollowingthestepsbelow.
1.NeweSeriesorNewcSeries:
i.Selectingalocation,objectortargeton-screenandpressing
theOkbutton.
2.Touchscreenmultifunctiondisplays:
i.Selectinganobjectortargeton-screen.
ii.Selectingandholdingonalocationon-screen.
ConguringMARPAoptions
Fromtheradarapplication:
1.SelectMenu.
2.SelectTrackTargets.
3.SelectMARPAOptions.
Note:IfAISdataisavailablethemenuwillbeMARPA&AIS
Options.
4.SelectVectorLength.
5.Selectanappropriatetimeperiod.
Thedistancethatyourvesseltravelsinthetimeperiodyou
specifyheredeterminesthelengthofthevectorlines.
6.SelectMARPATargetHistory.
7.Selectanappropriatetimeperiod.
Thetarget'spreviouspositionwillbeplottedontheradardisplay
asatargeticonwithlightershadingthantheactualtarget.
Note:MARPAandAISfunctionsshareSafeZoneandVector
Lengthsettings.
ConguringsafezonesetupforMARPA
FromtheRadarapplication:
1.SelectMenu.
2.SelectTrackTargets.
3.SelectSafeZoneSet-up.
4.SelectSafeZoneRadius.
i.SelectadistancefortheSafeZone.
Thisisthedistancefromyourvesselthatthesafezonewill
besetup.
5.SelectTimetoSafeZone.
i.Selectatimeperiod.
Atargetisconsidereddangerousifitwillenteryoursafe
zonewithinthistimeperiod.
6.SelectSafeZoneRing.
Selectingsafezoneringwillswitchbetweenshowingandhiding
thesafezoneringintheradarapplication.
UsingMARPA
AcquiringaMARPAtargettotrack
Fromtheradarapplication:
1.Selectthetargettobeacquired.
TheMARPAcontextmenuisdisplayed.
2.SelectAcquireTarget.
The“targetbeingacquired”symbolisdisplayed.Ifthetargetis
presentforseveralscans,theradarlocks-ontothetarget,andthe
symbolchangesto“safetarget”status.
CancellingaMARPAtargetusingtheMARPAcontextmenu
Fromtheradarapplication:
1.Selecttherelevanttarget.
TheMARPAcontextmenuisdisplayed.
2.SelectCancelTargetorCancelAllTargets.
CancellingaMARPAtargetusingthemenu
1.SelectMenu.
2.SelectTrackTargets.
3.SelectViewMARPALists.
Note:IfAISdataisavailablethemenuwillbeViewMARPA&
AISLists.
4.SelectViewMARPAList.
5.SelecttherelevantMARPAtargetfromthelist.
6.SelectCancelTargetorCancelAllTargets.
Usingradar
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