A system for determining an object position on a site with large machinery, particularly a mine site, a construction site, or an agricultural area, based on radio frequency time-of-flight ranging. The system is configured to determine a current position of a reference point indicative of a position of a machine on the site, to access an arrangement dataset indicative of a positional relationship between the reference point and a mounting location on the machine of at least one anchor of a point-to-point radio ranging unit, and to determine a position of the at least one anchor based on the current position of the reference point and the arrangement dataset, wherein the position of the at least one anchor is provided to a position determining unit configured for determining position information of tags based on ranging data of the point-to-point radio ranging unit.