Sub 10−16 frequency transfer with IPPP: Recent results

The Precise Point Positioning (PPP) technique using GPS phase and code observations is widely used to compute time and frequency links. We have shown that a PPP technique where the integer nature of phase ambiguities is preserved provides significant improvement over the classical use of floating ambiguities. We show examples that all indicate that this Integer-PPP (IPPP) technique allows frequency comparisons with 1×10
^-16
accuracy in a few days, improving with longer averaging, and can be readily operated with existing products.