So with WGS-84 and the ITRF, we changed to a different coordinate system with a meridian that goes 102.5m east of the Greenwich observatory. This was done to ke

So with WGS-84 and the ITRF, we changed to a different coordinate system with a meridian that goes 102.5m east of the Greenwich observatory. This was done to keep continuity in UT1 time.[0] [0] http://link.springer.com/article/10.1007%2Fs00190-015-0844-y http://link.springer.com/article/10.1007%2Fs00190-015-0844-y