Instruction Manual

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7430‐0808‐01Rev.B
Page90
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GNAV540UserManual
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YHardIronBias 0x000A I2 2/2^16 Gauss
SoftIronScaleRatio 0x000B U2 2/2^16 ‐
SoftIronAngle 0x000E I2 2*pi/2^16 Radians
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Notethatthecalibrationvaluesforanexternalmagnetometerarecontainedindistinctfields:
Table61ExternalMagnetometerCalibrationValues
FieldName FieldID Format Scaling Units
XHardIronBias 0x001C I2 2/2^16 Gauss
YHardIronBias 0x001D I2 2/2^16 Gauss
SoftIronScaleRatio 0x001E U2 2/2^16 ‐
SoftIronAngle 0x001F I2 2*pi/2^16 Radians
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oranexternalmagnetometer,therearealsoconfigurationfieldsthatallowausertospecifyrollandpitchoffsets
0x0017,0x0018),andmagnetometerorientation(0x0020).
F
(
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Thehardironbiasvaluesarescaledfrom(‐1,1)Gauss.Thesevaluesaresubtractedfromthetangentplane
magnetometervectorbeforeheadingiscalculated.Thesoftironscaleratioisscaledfrom(0,2)andismultipliedby
thetangentplanexmagnetometervaluebeforeheadingiscalculated.
HeadingTrackOffset
Thisfieldisusedtosettheoffsetbetweenvehicleheadingandvehicletracktobeusedbythenavigationmodefilter
whennomagnetometerheadingmeasurementsareavailable.
FieldName FieldID Format Scaling Units
HeadingTrackOffset 0x000C I2
2*pi/2^16
(360°/2^16)
Radians(heading‐track)
(°)
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CommandstoProgramConfiguration
WriteFieldsCommand
Table62WFCommand
WriteFields 746(‘WF’=0x5 )
Preamble PacketType Length Payload Termination
0x5555 0x5746 1+numFields*4 <WFpayload> <CRC(U2)>
Thiscommandallowstheusertowritedefaultpower‐upconfigurationfieldstotheEEPROM.Writingthedefault
configurationwillnottakeeffectuntiltheunitispowercycled.
NumFieldsisthenumberofwordstobewritten.
The
field0,field1,etc.arethefieldIDsthatwillbewrittenwiththefield0Data,field1Data,etc.,respectively.Theunit
willnotwritetocalibrationoralgorithmfields.