[time-nuts] Adafruit Ultimate GPS timing message arrival times

Brooke Clarke brooke at pacific.net
Sat Jul 30 16:50:15 EDT 2016


Hi Mark:

Isn't this the receiver that hears a very large number of GNSS satellites and also has a 10 Hz update rate?
If so, I'd expect that there would a large variation in message lengths.  How stable  is the 10 PPS or 1 PPS output?

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

-------- Original Message --------
> A couple of people have asked about the poor message arrival time performance of the popular Adafruit Ultimate GPS receiver.   I modified Lady Heather to analyze the message arrival times using a histogram instead of a simple average.  When I looked at the histogram data (.01 msec resolution), I was rather shocked...  With an hour of data,  most receivers have maybe a couple dozen bins hit,  with the peak bin several hundred counts above the next lower peak.   The Adafruit had over 1800 bins hit, with the peak bin having six hits.   Attached is the histogram...  you probably don't want to use this receiver to drive a clock based upon message arrival times...
>
>
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