Inside the Trimble X9: Deep Dive into Trimble X9 Auto-Calibration 8
Collimation Modes
Theinternalcollimatorisusedintwodifferentmodestoperformtheautomaticcalibration.
▪ Auto collimation mode—Internalcollimatorcamerameasuresthecenterunitmirrortothe
frontandbacksideforthetrunnionaxiserror.
▪ Collimation mode—InternalcollimatorcamerameasuresEDMshotsoverthevertical
deflectionangleforhorizontal&verticalcollimationerrors.
Internal Collimator Measurements and Calculations
Measuringhorizontalandverticalcollimationerrorsofthesightingaxisisanautomaticprocessof
positioningtheverticaltelescopemovementssothatthelasersightingaxispointsdirectlyintothe
nadir.Thelaserspotwillbeidentifiedwiththeinternalcollimatorcamerainthebaseunitandwill
bemeasuredwiththecenterofgravity.Keepingtheverticalpositionasitis,theinstrumentwill
turnafullcirclehorizontally,permanentlymeasuringthespotpositiononthecamerachip.The
givenfigureofthespotwillbeexactlyacirclewithacenterrepresentingtheverticalaxis.
Atleasttwomeasurementsarerequiredforconstanthorizontalangleanddifferentvertical
directions.Bothpointsaredefiningaline.Thefootdroppedperpendicularfromthecirclecenter
willbecalculated.Thedeviationequatestoverticalcollimationerror.Thedistancebetweencircle
centerandthefootprintdefinestheblindspotorthesumoftheinstrumenttrunnionaxiserror"k"
andhorizontalcollimationerror"c."Incasethetrunnionerrorisknownthehorizontalcollimation
errorcanbecalculated.
Figure 4: Internal Collimator Measurements and Calculations
