TIME STABILITY AND ELECTRICAL DELAY COMPARISON OF DUAL- FREQUENCY GPS RECEIVERS

摘要

Some dual-frequency GPS receivers have been used for time comparisons for several years. They are now standard equipment for operational units in time laboratories. Evaluation of these receivers is necessary to ensure accuracy and long-term stability of time links used in TAI and in precise time station (PTS) dedicated to GALILEO. Currently, the most widely approach used to determine the electrical delay and the time stability of these devices is the differential method developed by the BIPM. Another solution is the calibration and the evaluation of receivers in using an artificial signal simulated by a GNSS signal simulator. This method was first defined and performed by Colorado University and put into operations by the Naval Research Laboratory (NRL). Since 2005, CNES (French Space Agency) has been developing this method with a similar approach. CNES proposed an evaluation and a calibration of three types of these time receivers, Ashtech Z12-T, Septentrio PolaRx2, and Dicom GTR50, in using the simulated method.