Initial Testing of a New GPS Receiver, the PolaRx2, for Time and Frequency Transfer Using Dual-Frequency Codes and Carrier Phases

Abstract : To contribute to TAI, the Royal Observatory of Belgium (ROB) routinely performs all-inview time transfer using an Ashtech Z-XII3T GPS receiver and the in-house-developed RINEXCGGTTS conversion software. In order to anticipate the renewal of that kind of time transfer equipment, the ROB started to test a new geodetic GPS receiver, the PolaRx2, developed by Septentrio (Belgium), for suitability for time transfer applications. Our results, obtained using codes as well as carrier phases, show that this receiver is very promising, with a 1 pps input port, and a very low noise level on the codes. However, we proposed and started to evaluate some hardware and firmware adaptations to improve its performances for continuous and precise (sub-ns) time transfer. The present firmware release indeed introduces clock discontinuities at each receiver reset, and produces variations at the level of tenths of nanosecond due to internal temperature variations related to changes in the processor load (depending on the number of used channels).