The stability of differential delays between Global Navigation Satellite receivers is critical for time and frequency transfer. We study the limit of this transfer between two specific receivers from the study of data taken from these receivers while they were connected with a splitter to the same antenna for 128 days. We show that the C/A to P1 TDEV stability is consistent with a flicker PM model at 0.5 ns from 1-10 d. The TDEV stability of differential code shows models of flicker PM at under 50 ps for C/A code, and white PM starting at under 100 ps at 1 d for P2 code. P3 code transfer would perhaps be limited by receiver variations to about 400 ps flicker PM. Carrier-only transfer shows a rate offset of +2x10-16 for L1 and -2x10-16 for L2. Thus a carrier-only frequency transfer technique would be limited to 8x10-16 for the ionosphere-free combination.
Limits on GPS Carrier Phase Time Transfer, Proc. 2009 PTTI Mtg., Santa Ana Pueblo, NM, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=904263
(Accessed September 30, 2023)