System for determining the position of moving objects

To reduce the transfer capacity requirements for correction data in a differential GPS system, while notably improving the interpretability of any correction data having suffered transmission interference and ensuring that such correction be as up to date as possible, continuous error readings (7) are calculated from a steady stream of GPS signals (12, 22, 32, 42) received from a reference GPS receiver (50) and from the known co-ordinates of its location (6). According to the invention, an evaluation system (60) is provided which, at a specific point in time recalculates the correction readings rounded off to the last full minute. The correction reading (8), calculated by the evaluation system, is then transmitted by at least one radio transmitter (80) in a radio data signal (RDS) included in its programme signal. Attached to the mobile object (5), whose situation co-ordinates are determined by a mobile GPS receiver (120), is a radio receiver (90) to which are connected an RDS decoder (100) for receiving and decoding the received RDS signals incorporating the processed correction readings (8) and a computer (110) which extracts the correction readings (7) from the decoded RDS and updates them to the present time. The computer also reconstructs a standard correction signal (7) complying with the RTCM standard. The reconstructed, standard correction data are finally fed to the GPS receiver which then corrects its reading according to the reconstructed correction readings (7) received.