Owner's manual
Page18
NAV440UserManual
7430‐0131‐01Rev.F
• Coupledtothe6‐DOFMEMSinertialsensorclusterisahighperformanceDigitalSignalProcessor(DSP)that
utilizestheinertialsensormeasurementstoaccuratelycomputenavigationinformationincludingattitude,
40Series
heading,andlinearvelocitythrudynamicmaneuvers(actualmeasurementsareafunctionofthe4
unitasshowninTable2).
TheDSPprocessormakesuseofinternalandexternalmagneticsensorand/orGPSdatatoaidthe
performanceoftheinertialalgorithmsandhelpcorrectlongtermdriftandestimateerrorsfromtheinertial
sensorsandcomputations.Thenavigationalgorithmutilizesamulti‐stateconfigurableExtendedKalman
Filter(EKF)tocorrectfordrifterrorsandestimatesensorbiasvalues.Thisalgorithmrunsona150MHz
32‐bitDSPthathasapproximatelyfourtimesthecomputationalpowerofMoogCrossbow’searlier
generationInertialSystems.
• Anotheruniquefeatureofthe440Seriesistheextensivefieldconfigurabilityoftheunits.Thisfield
configurabilityallowsthe440SeriesofInertialSystemstosatisfyawiderangeofapplicationsand
performancerequirementswithasinglemassproducedhardwareplatform.Thebasicconfigurability
includesparameterssuchasbaudrate,packettype,andupdaterate,andtheadvancedconfigurability
gthe
includesthedefiningofcustomaxesandhowthesensorfeedbackisutilizedintheKalmanfilterdurin
navigationprocess.
The440SeriesispackagedinafullysealedlightweighthousingwhichprovidesEMI,vibration,andmoisture
resistancetolevelsconsistentwithmostland,marine,andairborneenvironments.The440SeriesutilizesanRS‐
232seriallinkfordatacommunication,andeachdatatransmissionincludesaBIT(Built‐In‐Test)messageproviding
systemhealthstatus.The440SeriesissupportedbyMoogCrossbow’sNAV‐VIEW2.X,apowerfulPC‐based
operatingtoolthatprovidescompletefieldconfiguration,diagnostics,chartingofsensorperformance,anddata
oggingwithplayback.
l
SummaryofMajorChangesfromthe300/400Seriesandthe420Series
MechanicalSizeandFootprint
ThemechanicalfootprintofMoogCrossbow’snew440SeriesInertialSystemsiscompatiblewithpriorgeneration
InertialSystemsincludingMoogCrossbow’s400Series(IMU400,VG400,AHRS400)andtheNAV420Series
products.Themountingplatefootprintisthesameandtheconnectorlocationisidentical.The440Seriesunits
areshorterthantheirequivalent400Seriesproduct(i.e.theAHRS440isshorterthantheAHRS400,etc).The440
SeriesunitisdimensionallyequivalenttotheNAV420.Fordetailedmechanicalandinstallationdrawings,referto
.
AppendixE. MechanicalSpecifications
ConnectorPinOut&OperatingVoltage,Current
TheDB‐15maleconnectoronMoogCrossbow’s440SeriesInertialSystemshasabackwardcompatiblepinout
withthe400Seriesand420Series.However,the440Serieshasasecondaryoptional‐usecommunicationsportfor
internalorexternalGPS.
OperatingPerformanceandAccuracy
The440Serieshasbeencharacterizedinawiderangeoflandandairborneapplications.Inthequalification
testing,thedynamicaccuracyofthe440Serieshasshownsuperiorperformancewhencomparedtotheequivalent
modelof400and420Series,reducingattitudeestimationerrorsinhalfduringcertaincriticaldynamicmaneuvers
withouttheuseofGPSaiding.WithGPSaidingintheNAV440,attitudeestimationisimprovedbyanorderof
magnitudecomparedwith400seriesproducts.Recommendedconfigurationsettingsarediscussedin
.The440Seriesfunctionsarediscussedin
AppendixB.
ApplicationExamples Chapter2.440SeriesFunctions.