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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MTi or MTx coordinate frame before (A) and after (B) object reset. The new Z‐axis of the sensor coordinate
framewillbealongthevertical.ThenewdirectionoftheX ‐axiswillbetheoldX–axisthatisprojectedon the
horizontalplane.
4.6.5 Alignmentreset
ThealignmentresetsimplycombinestheObjectresetandtheHeadingresetatasingleinstantintime.This
hastheadvantagethatallco‐ordinatesystemscanbealignedwithasingleaction.Keepinmindthatthenew
globalreferencex‐axis(heading)isdefinedbytheobjectX‐axis(towhichXZ‐planeyouhavealignedtheMTi/
MTx).
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NOTE:Oncethisalignmentresetisconducted,bothcalibrateddataandorientationwillbeoutputwithrespect
tothenewS’coordinateframe.
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4.7 Timestampoutput
Timestampoutputcanbeenabledordisabled(usingtheSetOutputSettings message).Thetimestamp
isalwayslastinthedatafieldoftheMTDatamessage.
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Currently, there is one option for the timestamp output, the sample counter which is a 16 bit counter
increasingwith1witheachMTDatamessagesent.Afterreaching(2^16)‐1=65535thesamplecounterwill
wraptozero(0).
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4.8 TestandCalibrationCertificate
EachMTiandMTxisaccompaniedbyanindividualTestandCalibrationCertificate.Thiscertificatestatesthe
calibration values determined during the calibration of the MTi and MTx in Xsens’ calibration facilities. The
valuesareexplainedhereinshort:
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The“Specifications
”chaptercontainsthefullrangesandbandwidthsofthephysicalsensorsinside.
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The“Basictestresults
”describesthenoiseofthe3sensortypesanditcontainsresidualsinorientation.
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Noise Thenoiseontheindividualsensorsignals
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Staticaccuracyresidual Theresidualcalibrationerrorforstaticorientationsatroomtemperature
Temperatureresidual The residual calibration error for static orientations over the temperature
range
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“Calibration data
” are the values that describe the conversion from the physical phenomenon to a digital
outputinanorthogonalcoordinatesystem:
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Gains(bits):Gains(orscalefactor)describetherelationbetweenthedigitalreadinginbitsandthemeasured
physicalsignal.
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Offsets(bits):Digitalreadinginbitsofthesensornophysicalsignalismeasured.
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Alignmentmatrix:Non‐orthogonalityofthesensortriade.Thisincludesnon‐orthogonalityintheorientation

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Theresolutionofthesensorsignalsarealwayslimitedbythenoiseinthesensorsignal,notbytheaccuracy
or resolution of the analog to digial converter. Exceptions are the temperature and static pressure sensor
wherequantizationcanbesignificant.