14.4GPSCheck
CheckingGPSoperation
YoucancheckthattheGPSisfunctioningcorrectly
usingthechartapplication.
FromtheHomescreen:
1.SelecttheChartapplication.
2.Checkthescreen.
Youshouldsee:
Yourboatposition(thisindicatesaGPSx).
Yourcurrentpositionisrepresentedbyaboat
symbolorsolidcircle.Yourpositionisalso
displayedinthedatabarunderVESPOS.
Asolidcircleonthechartindicatesthatneither
headingnorCourseOverGround(COG)data
isavailable.
Note:Raymarinerecommendsthatyoucheckthe
displayedvesselpositionintheChartapplication
againstyouractualproximitytoaknowncharted
object.GPS/GNSSreceiverstypicallyhavean
accuracyofbetween5and15m.
Note:AGPSStatuspageisavailablefromthe
GPSSet-upmenu:(Homescreen>Set-up>
SystemSettings>GPSSet-up>ViewSatellites
Status).ThisprovidesHDOPandEHPEdata
whichcanprovideanindicationofhowaccurate
yourvessel’sGPSpositionis.
GNSSStatus
TheGPSstatuspageenablesyoutoviewthestatus
oftheavailablesatellitesthatarecompatiblewith
yourreceiver.
Thesatelliteconstellationsareusedtopositionyour
vesselintheChartandWeatherapplications.You
cansetupyourreceiverandcheckitsstatusfrom
theGPSSet-upmenu:Homescreen>Set-up>
SystemSettings>GPSSet-up.Foreachsatellite,
thescreenprovidesthefollowinginformation:
1.Skyview
2.Satellitestatus
3.Positionandxinformation
Skyview
Skyviewisavisualrepresentationthatshows
thepositionofnavigationsatellitesandtheirtype.
Satellitetypesare:
•Circle—Acircleidentiesasatellitefromthe
GPSconstellation.
•*Diamond—Adiamondidentiesasatellitefrom
theGLONASSconstellation.
•Square—Asquareidentiesan(SBAS)
differentialsatellite.
Note:*GLONASSsatellitesareonlyavailable
whenconnectedtoacompatibleGNSSreceiver.
RefertotheTechnicalspecicationforyour
producttoidentifyyourreceivertype.
Satellitestatusarea
TheSatellitestatusareadisplaysthefollowing
informationabouteachsatellite:
•Type—Identieswhichconstellationthesatellite
belongsto.
•ID—Displaysthesatellitesidenticationnumber.
•CNO(Carrier-to-noiseratio)—Displaysthesignal
strengthofeachsatelliteshownintheSkyview:
–Grey=searchingforsatellite
–Green=satelliteinuse
–Orange=trackingsatellite
•AzimuthandElevation—Providestheangleof
elevationandazimuthbetweenthelocationofthe
receiverandthesatellite.
Positionandxinformation
Thefollowingpositionalandxinformationis
provided:
•HorizontalDilutionofPrecision(HDOP)
—HDOPisameasureofsatellitenavigation
accuracy,calculatedfromanumberoffactors
includingsatellitegeometry,systemerrorsin
thedatatransmissionandsystemerrorsinthe
receiver.Ahigherguresigniesagreater
positionalerror.Atypicalreceiverhasanaccuracy
ofbetween5and15m.Asanexample,assuming
areceivererrorof5m,anHDOPof2would
representanerrorofapproximately15m.Please
rememberthatevenaverylowHDOPgureis
NOguaranteethatyourreceiverisprovidingan
accurateposition.Ifindoubt,checkthedisplayed
vesselpositionintheChartapplicationagainst
youractualproximitytoaknownchartedobject.
•EstimatedHorizontalPositionError(EHPE)
—EHPEisameasureoftheestimatederrorof
apositionxinthehorizontalplane.Thevalue
displayedindicatesthatyourpositioniswithina
circleradiusofthestatedsize50%ofthetime.
•Fixstatus—indicatestheactualmodethe
receiverisreporting:
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LightHouseMFDoperationinstructions