The U.S. Space Force has publicized the Antenna Phase Center Offsets of the L1, L2 and L5 signals for the Earth Coverage (EC) antenna deck, as well as the Timing Group Delay (TGD) and inter-signal correction (ISC) values as measured at the factory for GPS-III SVN-79. The data can be found on the GPS Technical References page of the U.S. Coast Guard Navigation Center:
