distance, perpendicular to the beam path, between two measurements of a stationary retroreflector, where the second measurement is taken with the laser tracker azimuth angle at approximately 1800 from the first measurement and the laser tracker elevation angle is approximately the same, statsionaarse pöördpeegeldiga kahel mõõtmisel saadud kauguse mõõdise erinevus, kus teine mõõtmine tehakse laserjälguriga sihinurgaga ligikaudu 1800 esimese mõõtmise sihist ja laserjälguri enda tasandinurk on mõlemal mõõtmisel sama