Owner's manual


NAV440UserManual
7430‐0131‐01Rev.F
Page29
Setting DefaultValue Comments
Freely
Integrate
OFF
TheFreelyIntegratesettingallowsausertoturntheunitintoafreegyroscope.In
freegyroscopemode,theroll,pitchandyawarecomputedexclusivelyfrom
angularratewithnoKalmanfilterbasedcorrectionsofroll,pitch,oryaw.When
turnedon,thereisnocouplingofaccelerationbasedsignalsintotherollandpitch
tch,and
ormagnetometerbasedsignalstotheyaw.Duetosensorbias.,theroll,pi
yawoutputswilldriftroughlylinearlywithtime.
Forbestperformance,theFreelyIntegratemodeshouldbeusedafterthe
algorithmhasinitialized.ThisallowstheKalmanFiltertoestimatetherolland
pitchrat
thefree
esensorbiaspriortoenteringthefreegyroscopemode.Uponexiting
gyroscopemode(OFF),oneoftwobehaviorswilloccur:
nds,
Iftheunithasbeeninfreelyintegratemodeforlessthansixtyseco
thealgorithmwillresumeoperationatnormalgainsettings
Iftheunithasbeeninfreelyintegratemodeforgreaterthansixty
seconds,thealgorithmwillforcearesetandreinitializewithhighgains
automatically.
UseMags ON
The
fory
UseMagssettingallowsuserstoturnonandoffthemagnetometerfeedback
aw/headingstabilization.
ThedefaultsettingisON.WhenUseMagsisturnedON,the440Seriesunit
usesthemagneticfieldsensorreadingstostabilizethedriftinyaw,andit
slavesthe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driftandfreelyintegrate.Ineffect,thissettingconvertsthe
bedoneon
functionalitytoVG.However,unlikeaunitintheVG440,thiscan
aselectablebasisandchangedinrealtimeduringamission.
Thereasonforthissettingistogivetheuseranabilitytoturnoffthe
magnetometerstabilizationwhenseveremagneticdistortionmaybeoccurring.
Thissettingisdesirablewhentheusersystemtemporarilymovesinclose
proximitytoalargeferrousobject.WhentheUseMagsswitchisturnedfrom
FFtoON,theunitwillreinitializetheyaw/headinganglewiththecompass
eadingprovidedfromthemagneticfieldsensorreadings.
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