Instruction Manual

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GNAV540UserManual
7430‐0808‐01Rev.B
Page33
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Setting Def eaultValu Comments
Orientation
See
Figure4on
page
24.
Toconfiguretheaxisorientation,selectthedesiredmeasurementforeachaxis:
NAV‐VIEW2.2willshowthecorrespondingimageoftheunit,soiteasyto
visualizethemodeofoperation.Referto
OrientationFieldonpage86forthe
intsthe
twentyfourpossibleorientationsettings.Thedefaultsettingpo
connectorAFT.
Freely
Integrate
OFF
TheFreelyIntegratesettingallowsausertoturntheunitintoafreegyroscope.In
freegyroscopemode,theroll,pitchandyawarecomputedexclusivelyfrom
angularratewithnoKalmanfilterbasedcorrectionsofroll,pitch,andyaw.When
turnedon,thereisnocouplingofaccelerationbasedsignalsintotherolland
pitchormagnetometerbasedsignaltotheyaw.Asaresult,theroll,pitch,and
yawoutputswilldriftroughlylinearlywithtimeduetosensorbias.Forbest
performance,theFreelyIntegratemodeshouldbeusedafterthealgorithmhas
initialized.ThisallowstheKalmanFiltertoestimatetherollandpitchrate
sens
gyro
orbiaspriortoenteringthefreegyroscopemode.Uponexitingthefree
scopemode(OFF),oneoftwobehaviorswilloccur
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Iftheunithasbeeninfreelyintegratemodeforlessthansixtyseconds,the
algorithmwillresumeoperationatnormalgainsettings
 Iftheunithasbeeninfreelyintegratemodeforgreaterthansixtyseconds,
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thealgorithmwillforcearesetandreinitializewithhighgainsautomatically.
UseGPS ON
TheUseGPSsettingenablesturningonandofftheGPSfeedback.Thedefault
settingisON.WhenUseGPSisturnedOFF,theunit’sbehaviorwillreverttothat
ofAHRSFunction.
Stationary
YawLock
OFF
ThissettingdefaultstoOFF;itisrecommendedtobeOFFforNAVFunction.The
stationaryyawlockisonlyrecommendedforconsiderationwhentheunitis
operatingwithGPS(UseGPS=ON)andWITHOUTmagnetometerfeedback(Use
Mags=OFF).Stationaryyawlockmaybeappropriateiftheuserplatformisa
groundvehicle.
UseMags ON
TheUseMagssettingenablesturningonandoffthemagnetometerfeedbackfor
yaw/headingstabilization.ThedefaultsettingisON..WhenUseMagsisturned
ON,theunitusesthemagneticfieldsensorreadingstostabilizethedriftinyaw,
slavesthe
andit yawtothecompassreadingprovidedfromthemagneticfield
sensorreadings.
When
UseMagsisturnedOFF,theheading(yaw)anglemeasurementoftheunit
willbeslavedtotheGPSheadingifGPSisavailable,otherwisetheheadingwill
ffthe
.
driftfeely.Thereasonforthissettingistogivetheuseranabilitytoturno
magnetometerstabilizationwhenseveremagneticdistortionmaybeoccurring
Thissettingisdesirablewhentheuservehicletemporarilymovesinclose
proximitytoalargeferrousobject.WhentheUseMagsswitchisturnedfrom
OFFtoON,theunitwillreinitializetheyaw/headinganglewiththecompass
readingprovidedfromthemagneticfieldsensorreadings.