SATMIX Time-Scale Comparisons Using a Single-Channel Fast-Sequencing GPS Receiver with Carrier-Phase Smoothing

Abstract : Two single-channel fast-sequencing GPS receivers (of type K +K GPS5) tracking the GPS signals of all satellites in view and using carrier-phase smoothing have been studied in time-scale comparisons between the Physikalisch-Technische Bundesanstal (PTB) and the Technical University Graz (TUG). The receiver output signal is a IPPS pulse which is the physical representation of UTC(USNO) obtained as the average from the individual satellites (SATMIX). At PTB and TUG, the 1PPS is measured with respect to UTC(PTB) and UTC(TUG), respectively. After exchange of data, the time-scale differences UTC(PTB) - UTC(TUG) are calculated and compared with those obtained by the GPS common-view (CV) and TWSTT methods. These comparisons show that the daily mean values of UTC(PTB) - UTC(TUG) found with the SATMIX technique are by only a factor of 2 more noisy (about 4 ns) than those obtained with the CV and TWSTT methods (about 2 ns). Measurement results over about 1 year are presented. It appears that the SATMIX technique is an useful alternative method for time comparisons. An advanced version (K+K GPS5-2K) based on the same principle as the K+K GPS5 is under development. The expected features of the advanced receiver are described briefly.