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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amount of disturbance. Errors in yaw/heading due to such distortions can be quite large, since the earth
magneticfieldisveryweakincomparisontothemagnitudeofmanysourcesofdistortion.
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Whether or not an object is ferromagnetic should preferably be checked by using the MTi’s or MTx’s
magnetometers.Itcanalsobe checkedwithasmall magnet,but be careful, you can easily magnetize hard
ferromagnetic materials, causing even larger errors. If you find that some object is magnetized (hard iron
effect), this is often the case with for example stainless steels that are normally not magnetic, it may be
possibleto“degauss
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”theobject.
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In most cases when the disturbance of the magnetic field caused by placement of the MTi or MTx on a
ferromagnetic object can be corrected for using a specialized calibration procedure commonly known as a
“hard‐andsoftironcalibration”.Thecalibrationprocedurecanbeexecutedinafewminutesandyieldsanew
setofcalibrationparametersthatcanbewrittentotheMTi/MTxnon‐volatilememory.
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Thiscalibrationprocedureisimplementedinthesoftwaremodule“MagneticFieldMapper”thatcomeswith
theSDK.Themethodusedinthissoftwareisuniqueinthesensethatitallowsauserchosen  measurement
sequence (within certain constraints), and that it allows for full 3D mapping. 3D mapping is important in
applications,wheretheobjectisrotatingthroughasubstantialrangeoforientations(e.g.acamera).Normal
2D mapping is suitable in applications where the object moves more or less in a single plane (e.g. a car or
boat).
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Disturbance caused by objects in the environment near the MTi or MTx, like file cabinets or vehicles, that
move independently, with respect to thedevice cause a type of distortion that cannot be calibrated for
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.
However, the amount of error caused by the disturbance is significantly by XKF and this works best if the
correctXKFScenarioisselectedforyourapplication.
8 Importantnotices
8.1 EnvironmentalOperatingConditions
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The recommended operating temperature of the MTi / MTx hardware is between 0°C and 55°C ambient
temperature.If operatedoutsidethistemperaturerangeperformance maydecreaseorthe devicemightbe
damaged. Absolute maximum ratings are between‐20°C and 55°C. Fast transient temperature fluctuations
maycausesignificanttemperaturegradientsacrossthedevice.Suchgradientscannotbeproperlymodelledby
temperaturecompensationandmaythereforedecreaseperformance.Foroptimalperformancetheambient
temperatureshouldremainconstantasmuchaspossibleduringthemeasurement.
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NOTE: Never expose the MTi or the MTx to strong magnetic fields.  The MTiandMTx containthe absolute
possible minimum of ferromagnetic materials (“hard” and “soft” magnetic materials). Nonetheless, some
minor components can be magnetized permanently by exposure to strong magnetic fields. This will not
damagetheunitbutwillrenderthecalibrationofthemagnetometersuseless,typicallyobservedasa(large)
deviationinheading.For mildmagnetizationitmaybepossibleto compensateforthe magnetizationofthe
deviceby are‐calibration(magneticfieldmapping). Takingcarenottoexpose the MTior theMTxto strong
magnetic fields, such as close proximity of permanent magnets, speakers, electromotor, etc.will make sure
magnetizationdoesnotoccur.

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Degaussingisaproceduretoapplystrongalternatingmagneticfieldswithdecreasingmagnitudeinrandom
directiontoanobjectthathasbeenmagnetized.Theeffectofthestrongalternatingfieldsis toremoveany
magnetized(aligned)domainsintheobject.Ifyoudegauss,pleasemakesuretheMTiorMTxisnotanymore
ontheobject!
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Thistypeofdisturbanceisnon‐deterministic.