It was setup to only send GPRMC sentences. http://users.megapathdsl.net/~hmurray/time-nuts/RMC-hist.png Here is what it looks like over time: http://users.megapathdsl.net/~hmurray/time-nuts/RMC-offset.png There are interesting glitches at 3 hours and 23 hours. Anybody have any ideas about what would cause that? -- These are my opinions. I hate spam.

Hal, On 08/01/2016 05:49 AM, Hal Murray wrote: > > It was setup to only send GPRMC sentences. > http://users.megapathdsl.net/~hmurray/time-nuts/RMC-hist.png > > Here is what it looks like over time: > http://users.megapathdsl.net/~hmurray/time-nuts/RMC-offset.png > > There are interesting glitches at 3 hours and 23 hours. Anybody have any > ideas about what would cause that? This most likely is related to scheduling inside the RTOS of the GPS receiver. Due to the frequency difference between GPS second and internal clock processing that we can expect, the scheduling needs re-alignment. There is an overlap between "late" and "early" which indicate that a dynamic scheduling, so depending on when things get ready it gets early or late. Variations within each time-slot is then due to processing variations. Cheers, Magnus