Re: [gpsd-dev] Meaning of negative PPS offset?

[Greg Troxel]

"Gary E. Miller" <address@hidden> writes:

>> which is I think what you are saying.   So the bug is that in cases we
>> are saying.
>> 
>>    n - N = -40ms
>
> Which makes no sense.  The NMEA at time X never preceeds the PPS for time X.

As I understand it, this discussion is happening because of a device
which is sending NMEA in advance of the PPS edge.

>>  Or perhaps even to only capture PPS when it's within 200 ms
>> of the system clock.
>
> Which fails for older and slower GPS.

I meant system clock, not NMEA.  So it would work when the device was
synced via NTP coarsely.  But not standalone, which is a fair point.

(I didn't quote most of your message, because I basically am in
agreement with it - I knew my example times were not really quite right,
but that they weren't critical to the point.)


So the real issue is to find out if this device that seems to have
premature NMEA really does do that.

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