Precise Point Positioning technique for short and long baselines time transfer

In this work the clock parameters determination of several timing receivers TTS-4 (AOS, PL), ASHTECH-Z-XII3T (PTB, USNO) and SEPTENTRIO POLARX4TR (ORB,) by use of the Precise Point Positioning (PPP) technique were presented. The clock parameters were determined for several time links based on the data delivered by time and frequency laboratories mentioned above. The computations cover the period from June 1 2012 to May 31, 2013 and were performed in two modes with 7-day and one-month solution for all links. All RINEX data files which include phase and code GPS data were recorded in 30-second intervals. All calculations were performed by means of Natural Resource Canada´s GPS Precise Point Positioning (GPS-PPP) software based on high-quality precise satellite coordinates and satellite clock delivered by IGS as the final products. The received results were compared with the results obtained by GPS CV and TWSTFT. The used independent PPP technique is a very powerful and simple method which allows for better control of antenna positions in AOS and a verification of other time transfer techniques like GPS CV, GLONASS CV and TWSTFT. The precision of the PPP technique is only comparable to the glass fiber link PL-AOS realized at present by PL and AOS time labs. Currently PPP technique is one of the main time transfer methods used at AOS considerably improving and strengthening the quality of the Polish time scales UTC(AOS), UTC(PL), and TA(PL).