GLOBALSAT GH-615 User Manual - Manual (Page 50)

GH-615
Page 50
GMT
Greenwich Mean Time (GMT) is a term originally referring to
mean solar time at the Royal Observatory, Greenwich in
England. It is now often used to refer to Coordinated Universal
Time (UTC) when this is viewed as a time zone, although
strictly UTC is an atomic time scale which only approximates
GMT in the old sense. It is also used to refer to Universal Time
(UT), which is the astronomical concept that directly replaced
the original GMT.