Re: GPSD doesn't report signal dropout

[Gary E. Miller]

Yo Tom!

On Wed, 7 Oct 2020 15:30:53 +1300
Tom Isaacson <tom.isaacson@teknique.com> wrote:

> gpspipe files:
> https://www.dropbox.com/s/34wt0usoe29uap4/json.log?dl=0
> https://www.dropbox.com/s/m7zhce4wulv0o18/raw.log?dl=0

Got it.  Not corrupted like the earlier ones.  Same problem with the
missing timestamps in GPGGA and GPRMC.

Here is the event, run through gpsd git head:

$GPGGA,022038.00,3644.762563,S,17444.069733,E,1,06,1.1,53.0,M,37.0,M,,*42
$GPVTG,,T,341.7,M,0.0,N,0.0,K,A*0C
$GPRMC,022038.00,A,3644.762563,S,17444.069733,E,0.0,,071020,18.3,E,A,V*45
{"class":"TPV","mode":3,"time":"2020-10-07T02:20:38.000Z","ept":0.005,"lat":-36.746042717,"lon":174.734495550,"altHAE":90.0000,"altMSL":53.0000,"alt":53.0000,"epv":20.700,"magvar":18.3,"speed":0.000,"climb":-3.000,"epc":36.80,"geoidSep":37.000,"eph":20.900,"sep":26.600}
$GPGSA,A,2,06,07,11,19,22,30,,,,,,,1.4,1.1,0.9,1*28
$GPGSV,2,1,06,01,37,122,,13,21,278,,17,60,275,,24,,,,1*5F
$GPGSV,2,2,06,28,66,165,,39,,,34,1*57
[...]
$GPVTG,,T,,M,,N,,K,N*2C
$GPGSA,A,1,,,,,,,,,,,,,,,,*32
$GPGGA,,,,,,0,,,,,,,,*66
$GPRMC,,V,,,,,,,,,,N*53
$GPGSV,2,1,06,01,37,122,,13,21,278,,17,60,275,,24,,,,1*5F
$GPGSV,2,2,06,28,66,165,,39,,,34,1*57

No TPV gets pushed out due to the missing time.  You should file a
bugs with Qeuctel.  One for the missing times, and another for
the sentence reodering.

I'll sleep on it and maybe I'll get an idea for a workaround.

> Protocol document:
> https://www.dropbox.com/s/ie3v7ijhdjc9xre/Quectel_EC2526EC21_GNSS_AT_Commands_Manual_V11.894777683.pdf?dl=0

That describes their AT commands, which are not NMEA compatible.  It
mentions, but does not describe, what the NMEA is.  It does not even
mention what NMEA version they pretend to support.  So not useful
for gpsd purposes.  

Got any doc on their NMEA?  Without doc I'm mostly guessing.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

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