At 03:39 03 November 2008, 309 wrote:
Well...the VL gets run about twice a month...and had been up for a bit
of time before flight or comparison with the Garmin. And I try to
give it time to obtain an almanac (hoping this will update ephemeris
data) before flying.

This seems odd, based on the explanations above, the Garmin appears to
be displaying UTC, since it lines up well with the Atomic clock and
the Naval Observatory...so it has the 14 seconds added (?), or are
they subtracted...or is time relative??? (pun intended).

Is the VL then displaying GPS time (ahead of UTC)?

....or am I using the wrong sign convention -- leap seconds inserted
into UTC make it BEHIND GPS time?

Here I thought I'd found a way to make my 1-26 14 seconds faster...

Or is that Slower?

-Pete

UTC=GPS+Leap Seconds.

For a UTC (=GMT) reference try http://wwp.greenwichmeantime.com/

The Volkslogger uses 'GPS Time' in the GPS Engine, but adds Leap Seconds
before recording the time.

Try using the VL's Pilot Event Marker to mark the trace at a minute
change as shown on the above site, download the trace and see what time is
recorded for the PEV.
-
Tim Newport-Peace >
Skype: specialist_systems
http://www.spsys.demon.co.uk/icom.htm