User manual

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 DocumentMT0100P.N
©XsensTechnologiesB.V. MTiandMTxUserManualandTechnicalDocumentation
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TrueNorthvs.MagneticNorth
AsdefinedabovetheoutputcoordinatesystemoftheMTi/MTxiswithrespecttolocalMagneticNorth.The
deviationbetweenMagneticNorthandTrueNorth(knownasthemagneticdeclination)variesdependingon
your location on earth and can be roughly obtained from various models of the earth’s magnetic field as a
functionoflatitudeandlongitude.TheMTi/MTxcanacceptasettingofthedeclinationvalue.Thisisdoneby
settingthe“declination”intheMTManager,SDKorbydirectcommunicationwiththesensor.Theoutputwill
thenbeoffsetbythedeclinationandthusreferencedto“local”truenorth.
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4.1.3 North‐East‐Downoptionalaerospaceco‐ordinatesystemdefinitions
It is possible  to change the default local tangent plane Euclidean coordinate system to a North‐East‐Down
(NED)conventioncoordinatesystem.Thisisoftenusedinaerospaceapplications.ChangingtotheNEDsetting
willalso changethebody‐fixed sensorcoordinatesystem toa Zdowncoordinatesystem asindicatedin the
figurebelow.
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Figure4:MTinaNEDconventioncoordinatesystemFigure4:MTinaNEDconventioncoordinatesystem
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Local
Magnetic
North
Local
vertical
x
NED
y
NED
S
NED
MTi and MTx co-ordinate system
Z down
G
NED
Local tangent plane
Z down (North East Down)
X
NED
Z
NED
Y
NED
All co-ordinate systems are right handed.
z
NED