Re: Strangeness with speed

[Florian Kiera]

Am 18.02.22 um 10:11 schrieb Владимир Калачихин:

> 18.02.2022
>       00:45, Gary E. Miller пишет:
>       
> > gpsd is doing exactly as it should.
> >         
> >       
>       
>       Not. Think again.
>       
>

Maybe you should think again. gpsd does as it should be. Gary even explained why it gives out a 2nd TPV with a 0.2seconds gap, so it makes sense to me now.

The difference between sentences1 and sentences2 is that sentences2 has a GGA and a RMC pair (share the same time) while sentences1 reports a GGA alone and a RMC 0.2seconds later. Set the RMC time to the same time as the GGA and everything works just as good as in sentences2. So your NMEA is to blame. Time is very important.

cat sentences1.nmea | gpsdecode  
{"class":"TPV","device":"stdin","mode":2,"time":"2022-02-17T10:23:10.940Z","ept":0.005,"lat":61.078466667,"lon":28.259850000,"track":10.4900,"magtrack":21.2871,"magvar":10.8,"speed":0.005}
{"class":"TPV","device":"stdin","mode":2,"time":"2022-02-17T10:23:11.340Z","ept":0.005,"lat":61.078666667,"lon":28.259800000,"track":354.1500,"magtrack":4.9471,"magvar":10.8,"speed":0.319}
{"class":"TPV","device":"stdin","mode":2,"time":"2022-02-17T10:23:11.740Z","ept":0.005,"lat":61.078850000,"lon":28.259633333,"track":336.4100,"magtrack":347.2071,"magvar":10.8,"speed":1.523}
{"class":"TPV","device":"stdin","mode":3,"time":"2022-02-17T10:23:12.340Z","ept":0.005,"lat":61.079050000,"lon":28.259433333,"altHAE":55.8600,"altMSL":55.8600,"alt":55.8600,"magvar":10.8,"speed":61.907,"climb":-0.600,"geoidSep":0.000,"e
ph":0.000}
{"class":"SKY","device":"stdin","hdop":0.00}
{"class":"TPV","device":"stdin","mode":3,"time":"2022-02-17T10:23:12.750Z","ept":0.005,"lat":61.079216667,"lon":28.259116667,"altHAE":55.7100,"altMSL":55.7100,"alt":55.7100,"magvar":10.8,"speed":61.559,"climb":-0.366,"geoidSep":0.000,"e
ph":0.000}
{"class":"SKY","device":"stdin","hdop":0.00}
{"class":"TPV","device":"stdin","mode":3,"time":"2022-02-17T10:23:13.150Z","ept":0.005,"lat":61.079400000,"lon":28.258783333,"altHAE":55.5500,"altMSL":55.5500,"alt":55.5500,"magvar":10.8,"speed":68.054,"climb":-0.400,"geoidSep":0.000,"e
ph":0.000}
{"class":"SKY","device":"stdin","hdop":0.00}
{"class":"TPV","device":"stdin","mode":3,"time":"2022-02-17T10:23:13.550Z","ept":0.005,"lat":61.079566667,"lon":28.258450000,"altHAE":55.4300,"altMSL":55.4300,"alt":55.4300,"magvar":10.8,"speed":64.642,"climb":-0.300,"geoidSep":0.000,"e
ph":0.000}
{"class":"SKY","device":"stdin","hdop":0.00}
{"class":"TPV","device":"stdin","mode":3,"time":"2022-02-17T10:23:13.950Z","ept":0.005,"lat":61.079700000,"lon":28.258116667,"altHAE":55.5300,"altMSL":55.5300,"alt":55.5300,"magvar":10.8,"speed":58.331,"climb":0.250,"geoidSep":0.000,"ep
h":0.000}
{"class":"SKY","device":"stdin","hdop":0.00}
{"class":"TPV","device":"stdin","mode":3,"time":"2022-02-17T10:23:14.350Z","ept":0.005,"lat":61.079833333,"lon":28.257700000,"altHAE":55.7000,"altMSL":55.7000,"alt":55.7000,"magvar":10.8,"speed":67.382,"climb":0.425,"geoidSep":0.000,"ep
h":0.000}
{"class":"SKY","device":"stdin","hdop":0.00}
cat sentences1.nmea  
$GPRMC,102310.54,A,6104.696,N,02815.586,E,0.00,0.00,170222,,*38
$GPGGA,102310.94,6104.696,N,02815.586,E,1,06,0.0,61.740,M,0.0,M,,*63
$GPRMC,102310.94,A,6104.708,N,02815.591,E,0.01,10.49,170222,,*09
$GPGGA,102311.34,6104.708,N,02815.591,E,1,06,0.0,58.790,M,0.0,M,,*63
$GPRMC,102311.34,A,6104.720,N,02815.588,E,0.62,354.15,170222,,*3F
$GPGGA,102311.74,6104.720,N,02815.588,E,1,06,0.0,56.540,M,0.0,M,,*64
$GPRMC,102311.74,A,6104.731,N,02815.578,E,2.96,336.41,170222,,*38
$GPGGA,102311.94,6104.731,N,02815.578,E,1,06,0.0,56.100,M,0.0,M,,*67
$GPRMC,102312.94,A,6104.743,N,02815.566,E,3.30,331.85,170222,,*35
$GPGGA,102312.34,6104.743,N,02815.566,E,1,06,0.0,55.860,M,0.0,M,,*68
$GPRMC,102312.34,A,6104.753,N,02815.547,E,3.47,318.03,170222,,*37
$GPGGA,102312.75,6104.753,N,02815.547,E,1,06,0.0,55.710,M,0.0,M,,*67
$GPRMC,102312.75,A,6104.764,N,02815.527,E,3.52,318.67,170222,,*3F
$GPGGA,102313.15,6104.764,N,02815.527,E,1,06,0.0,55.550,M,0.0,M,,*64
$GPRMC,102313.15,A,6104.774,N,02815.507,E,4.06,318.14,170222,,*35
$GPGGA,102313.55,6104.774,N,02815.507,E,1,06,0.0,55.430,M,0.0,M,,*64
$GPRMC,102313.55,A,6104.782,N,02815.487,E,4.83,308.50,170222,,*3D
$GPGGA,102313.95,6104.782,N,02815.487,E,1,06,0.0,55.530,M,0.0,M,,*69
$GPRMC,102314.95,A,6104.790,N,02815.462,E,5.21,301.76,170222,,*30
$GPGGA,102314.35,6104.790,N,02815.462,E,1,06,0.0,55.700,M,0.0,M,,*6D
$GPRMC,102314.35,A,6104.794,N,02815.439,E,5.24,290.64,170222,,*31

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