GPS frequency transfer with IPPP

Since many years, the time community has been using the Precise Point Positioning (PPP) technique using GPS phase and code observations to compute time and frequency links. However progresses in atomic clocks imply that the performance of PPP frequency comparisons is now a limiting factor in comparing the best frequency standards. One main limiting factor comes from the effect on the clock solution of the simultaneous resolution of floating phase ambiguities together with other parameters. In this paper we study how to improve the PPP frequency transfer using the Integer-PPP (IPPP) technique implemented by the CNES.