Anovelopticaltestingtarget(OTT)withthreedegreesoffreedom(DOFs)isproposedformeasuringthetrackingperformanceofaphotoelectrictheodolite.Themaincomponents,suchastheazimuthaxissystem,thepitchingaxissystem,thelinearmotionsystem,andthesimulatedtargetgenerator,aredesigned.Furthermore,thelinearmodulewiththeformofalarge-spanandlow-stiffnesscantileverbeamisstrengthenedusinganintegratedoptimizationmethod.Afterthestructureisstrengthened,the1st-ordernaturalfrequencyincreasesfrom14Hzto32Hz.Finally,afunctionaltestisperformedandtheresultsshowthatcomparedwithatraditionalopticaltesttarget,thesimulatedtargetgeneratedbythenoveltargetisadvantageousinpractice.
