NavList:

Ummm - Washington DC is the capital of the USA and has been since the British yoke was rudely cast aside some years back. NY City is the financial capital, if that’s the term. 

Frank Reed will surely correct me if I am wrong, but as I understand it, the technical details Frank has explained from the article referenced accepted, the ‘Greenwich' or zero meridian of GPS is based on what is called the IERS (International Earth Rotation and Reference Systems Service) Reference Meridian. From what I understand this longitude is actually referenced to the longitude of the Johns Hopkins Applied Physics Laboratory, Howard County, Maryland, on the ellipsoid of the old North American Datum (1927) as a result of the way in which the old 1970s TRANSIT Doppler satellite navigation system was set up. So this 5.3 arc second ‘shift’ in the prime meridian dates from the early 1960s but only made the big difference with the adoption first of WGS72 and then of WGS84…and so on to any subsequent world geodetic system revision.

Whether that had any effect and to what extent it may have had it on the 102m displacement eastwards of the GPS zero from the nice line on the ground outside the old Royal Observatory in Greenwich Park I don’t know, but Frank Reed’s explanation would seem persuasive.

Best,

Stephen D