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  #53  
Old May 21st 19, 03:34 AM posted to rec.aviation.soaring
Dave Leonard
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Posts: 36
Default Implausible Time Records

Maybe has to do with waiting to get the current almanac to know how many leap seconds to apply to received GPS time to get to UTC time used for the logs? Waiting for the whole message can take over 10 minutes.


On Monday, May 20, 2019 at 6:38:44 PM UTC-6, kinsell wrote:
You would think 8 satellites would be plenty. Looking at some
discussion on the Ublox site, apparently it's more complicated than time
valid vs not valid. There's flags that differentiate between low
accuracy satellite time vs high accuracy. Probably of no significance
in our application. I'll bet the FR code could be tweeked to use
satellite time when they're recording x-y-z data.

Or you could be more conservative in making sure the gps is fully locked
up before takeoff, works for me. My recorders come on with the master,
by the time I'm ready for takeoff they've had plenty of time and
checking the displays confirms that.