Inside the Trimble X9: Deep Dive into Trimble X9 Auto-Calibration 4
Internal Collimator
Theintegrationofaninternalcollimatorinsidetheinstrumentbaseenablesacompletelyautomatic
calibrationprocess.Notargetsoruserinteractionarerequiredtomeasuretheprimaryaxiserrors.
Figure 2: Internal Collimator for Trimble X9
Theinternalcollimatorcamerameasuresthelaserbeamemittedbythescannerheadoverthefull
radius,whilethealidadedrivesystemturnsthecenterunittodifferentpositions.Theprocessof
measuringasingularlineofsighthorizontalandverticalcollimationerrorfromatotalstationis
extendedtoincludeinfiniteline-of-sightmeasurementstakenovera360°dome.Thisispossible
withtheTrimbleX-Drive'scombinationoftwoverticaldrivesystemslocatedinthealidadeandthe
deflectionunitforscanning.
Thisauto-calibrationprocedurecomeswithmultipleadvantages.Thefirstbeingthatbecausethe
technologyforthealidade'sencodersystemisadoptedfromtotalstations,theprecisionisalready
downtolessthan3"(arcseconds)andprovidesconfidencethatthescannerheadwillbeproperly
calibratedateachindividualdeflectionunitencoderpositionforbothhorizontalandvertical
collimationerror.Theprocedurealsoaccountsforallremainingalignmentdeviationsinsidethe
scanneraswellasdeflectionunitencodererrors.Forexample,inthecasethattheEDMbeamand
thedeflectionunitrotationaxesarenotidentical,thescanningplanewillnotbeperfect,butrather
slightlybent.
