Using of spirent GPS/Galileo HW simulator for timing receiver calibration

In this paper the absolute calibration of GPS time receivers with a Spirent GPS/Galileo HW simulator is analyzed and described in detail. The primary step is to calibrate the simulator itself. In this context the most important facts and values which have to be measured are explained. After the calibration of the simulator the receiver is fed with satellite signals generated by the simulator belonging to a standard GPS satellite constellation to determine the absolute offset of the receiver (internal delay) compared to the simulator output. The used GNSS hardware simulator provides GPS and Galileo signals in parallel and therefore additionally can be used for absolute calibration of combined GPS/Galileo or stand alone Galileo time receivers. As there are no such receivers available yet, the precision of the GPS and Galileo pseudoranges determined by a combined GPS/Galileo receiver is analyzed.