Instruction Manual

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Page34
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GNAV540UserManual
7430‐0808‐01Rev.B
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Setting DefaultValue Comments
RestartOn
OverRange
ON
Thissettingforcesanalgorithmresetwhenasensoroverrangeoccurs,i.e.,a
rotationalrateonanyofthethreeaxesexceedsthemaximumrange.Thedefault
settingisOFF..Algorithmresetreturnstheunittoahighgainstate,wherethe
unitrapidlyestimatesthegyroscopebiasandusestheaccelerometerfeedback
heavily.Thissettingisrecommendedwhenthesourceofover‐rangeislikelyto
besustainedandpotentiallymuchgreaterthantheratesensoroperatinglimit.
Largeandsustainedangularrateover‐rangesresultinunrecoverableerrorsin
rollandpitchoutputs.
AnunrecoverableerrorisonewheretheEKFcannotstabilizetheresultingroll
andpitchreading.Iftheover‐rangesareexpectedtobeofshortduration(<1
sec)andamodestpercentageoverthemaximumoperatingrange,itis
recommendedthattherestartonoverrangesettingbeturnedoff.Handlingof
anin nge
swit
ertialratesensorover‐rangeiscontrolledusingtherestartOnOverRa
ch.
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Ifthisswitchisoff,thesystemwillflagtheoverRangestatusflagand
continuetooperatethroughit.
 Ifthisswitchison,thesystemwillflagamasterFailerrorduringanover‐
rangeconditionandcontinuetooperatewiththisflaguntilaquasi‐static
conditionismettoallowforanalgorithmrestart.
Thequasi‐staticconditionrequiredisthattheabsolutevalueofeachlow‐pass
ratesensorfallsbelow3deg/sectobegininitialization.Thesystemwillthen
attemptanormalalgorithmstart.
Dynamic
Motion
ON
ThedefaultsettingisON.Turningoffthedynamicmotionsettingresultsina
highergainstatethatusestheaccelerometerfeedbackheavily.Duringperiodsof
timewhenthereisknownlowdynamicacceleration
TurnSwitch
Threshold
0.5deg/sec
Withrespecttocentripetalorfalsegravityforcesfromturningdynamics(or
coordinatedturn),theunitmonitorstheyaw‐rate.Iftheyawrateexceedsagiven
turnSwitchthreshold,thefeedbackgainsfromtheaccelerometersignalsfor
attitudecorrectionarereducedbecausetheyarelikelycorrupted.
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