Lora-net/lora_gateway

XTAL error calc not using NAV-TIMEGPS

pshep opened this issue · 1 comments

pshep commented

Should this:

lora_gateway/libloragw/src/loragw_gps.c

Line 678 in a955619

utc_diff = (double)(utc.tv_sec - (ref->utc).tv_sec) + (1E-9 * (double)(utc.tv_nsec - (ref->utc).tv_nsec));

Not use gps_time, not utc for calculating the 'slope'?

On a separate but related topic, I understand the NAV-TIMEGPS is used to avoid leap seconds in the NMEA stream, but why are they an issue? I assume it's got something to do with the possibility of time going backwards?

3rdly... right there we're measuring the time between PPS pulses. Should this not be expected to be exactly 1 second (within 30ns or so)? Why even measure the period over hard-coding to 1 second?

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