The invention relates to a method and system for the validation of satellite-based positioning. The system comprises a radio navigation device (10) installed on board a mobile carrier (2), including a satellite geo-positioning device (12) able to receive a composite radio signal including a plurality of radio navigation signals each transmitted by a transmitting satellite and including time-synchronization and position-reference information, the radio navigation device being able to carry out processing of the received radio navigation signals to calculate first navigation information including information on the geographical position, speed and time of the carrier.The radio navigation device (10) is capable of transmitting baseband digitized signals (IF1, . . . , IFN) from radio navigation signals received at the reference processing station (16), the reference processing station (16) is capable of carrying out processing (29) similar to the processing (20), carried out by said radio navigation device (10), of the digitized signals (IF1, . . . , IFN) in order to calculate second navigation information, and the system comprises means (22, 42) for validating the first navigation information in accordance with the second navigation information calculated by the reference processing station (16).