When my phone receives a message like this (copied from Bluetooth terminal on my Android phone):
$GPRMC,164705.600,A,5967.27144,N,967.48088,E,0.0330,144.12,010718,0.0,E,A*02
Then I find something like this is the log file (copied from v5.4.0 RaceChrono's NMEA log file):
$GPRMC,163246.300,A,6007.27314,N,01007.47758,E,0.05,168.02,010718,,,*22
The two $GPRMC sentences were recorded 15 minutes apart (the time stamps are both correct).
Both are recorded at same location, but only the first sentence contains the correct location.
Is there something wrong with the format of the first sentence that can cause RaceChrono to misinterpret the position?
Why does RaceChrono shift my position by approx 13.8 km?
I have configured the GPS to make only GPRMC (and $RC2), but the log contains also GPGGA-messages. I do not know where the GPGGA-messages come from -- seems like RaceChrono copies info from GPRMC into ghost GPGGA messages.
More lines from the Bluetooth terminal:
$GPRMC,171139.500,A,5967.27244,N,967.48079,E,0.1244,77.65,010718,0.0,E,A*33
$GPRMC,171139.600,A,5967.27243,N,967.48078,E,0.1147,77.65,010718,0.0,E,A*36
$GPRMC,171139.700,A,5967.27241,N,967.48079,E,0.0117,77.65,010718,0.0,E,A*30
$GPRMC,171139.800,A,5967.27239,N,967.48078,E,0.0855,77.65,010718,0.0,E,A*3E
$GPRMC,171139.900,A,5967.27238,N,967.48075,E,0.1263,77.65,010718,0.0,E,A*3D
$GPRMC,171140.000,A,5967.27237,N,967.48078,E,0.0292,77.65,010718,0.0,E,A*37
$GPRMC,171140.100,A,5967.27235,N,967.48077,E,0.0739,77.65,010718,0.0,E,A*3F
$GPRMC,171140.200,A,5967.27236,N,967.48078,E,0.1555,77.65,010718,0.0,E,A*39
$GPRMC,171140.300,A,5967.27234,N,967.48077,E,0.0700,77.65,010718,0.0,E,A*36
$RC2,,2542,,,,,,25.0,nan,50.0,40.0,0.0,0.0,0.0,0.0*77
$GPRMC,171140.400,A,5967.27233,N,967.48076,E,0.0778,77.65,010718,0.0,E,A*38
$GPRMC,171140.500,A,5967.27233,N,967.48071,E,0.2060,77.65,010718,0.0,E,A*32
$GPRMC,171140.600,A,5967.27233,N,967.48071,E,0.1361,77.65,010718,0.0,E,A*30
$GPRMC,171140.700,A,5967.27230,N,967.48070,E,0.1497,77.65,010718,0.0,E,A*3D
$GPRMC,171140.800,A,5967.27231,N,967.48069,E,0.0680,77.65,010718,0.0,E,A*3E
$GPRMC,171140.900,A,5967.27230,N,967.48070,E,0.0952,77.65,010718,0.0,E,A*36
$GPRMC,171141.000,A,5967.27229,N,967.48070,E,0.0661,77.65,010718,0.0,E,A*39
$GPRMC,171141.100,A,5967.27228,N,967.48071,E,0.0272,77.65,010718,0.0,E,A*3E
$GPRMC,171141.200,A,5967.27228,N,967.48070,E,0.1361,77.65,010718,0.0,E,A*3E
$GPRMC,171141.300,A,5967.27227,N,967.48070,E,0.0389,77.65,010718,0.0,E,A*37
$RC2,,2543,,,,,,25.0,nan,50.0,40.0,0.0,0.0,0.0,0.0*76
$GPRMC,171141.400,A,5967.27227,N,967.48069,E,0.0914,77.65,010718,0.0,E,A*36
$GPRMC,171141.500,A,5967.27226,N,967.48067,E,0.1905,77.65,010718,0.0,E,A*39
$GPRMC,171141.600,A,5967.27225,N,967.48067,E,0.1788,77.65,010718,0.0,E,A*32
$GPRMC,171141.700,A,5967.27224,N,967.48070,E,0.1263,77.65,010718,0.0,E,A*34
$GPRMC,171141.800,A,5967.27225,N,967.48073,E,0.0447,77.65,010718,0.0,E,A*38
$GPRMC,171141.900,A,5967.27223,N,967.48072,E,0.0369,77.65,010718,0.0,E,A*35
$GPRMC,171142.000,A,5967.27222,N,967.48070,E,0.0194,77.65,010718,0.0,E,A*3C
$GPRMC,171142.100,A,5967.27223,N,967.48071,E,0.1166,77.65,010718,0.0,E,A*31
...and from RaceChrono log file a couple of minutes later:
$GPRMC,171422.100,A,6007.27070,N,01007.48095,E,0.11,77.65,010718,,,*14
$GPGGA,171422.100,6007.27070,N,01007.48095,E,1,,,,M,,M,,*45
$GPRMC,171422.200,A,6007.27068,N,01007.48093,E,0.09,77.65,010718,,,*11
$GPGGA,171422.200,6007.27068,N,01007.48093,E,1,,,,M,,M,,*49
$GPRMC,171422.300,A,6007.27069,N,01007.48093,E,0.13,77.65,010718,,,*1A
$GPGGA,171422.300,6007.27069,N,01007.48093,E,1,,,,M,,M,,*49
$GPRMC,171422.400,A,6007.27069,N,01007.48092,E,0.04,77.65,010718,,,*1A
$GPGGA,171422.400,6007.27069,N,01007.48092,E,1,,,,M,,M,,*4F
$GPRMC,171422.500,A,6007.27070,N,01007.48091,E,0.06,77.65,010718,,,*12
$GPGGA,171422.500,6007.27070,N,01007.48091,E,1,,,,M,,M,,*45
$GPRMC,171422.600,A,6007.27071,N,01007.48089,E,0.07,77.65,010718,,,*18
$GPGGA,171422.600,6007.27071,N,01007.48089,E,1,,,,M,,M,,*4E
$GPRMC,171422.700,A,6007.27071,N,01007.48088,E,0.07,77.65,010718,,,*18
$GPGGA,171422.700,6007.27071,N,01007.48088,E,1,,,,M,,M,,*4E
$GPRMC,171422.800,A,6007.27071,N,01007.48087,E,0.03,77.65,010718,,,*1C
$GPGGA,171422.800,6007.27071,N,01007.48087,E,1,,,,M,,M,,*4E
$GPRMC,171422.900,A,6007.27072,N,01007.48088,E,0.04,77.65,010718,,,*16
$GPGGA,171422.900,6007.27072,N,01007.48088,E,1,,,,M,,M,,*43
$GPRMC,171423.000,A,6007.27072,N,01007.48086,E,0.06,77.65,010718,,,*12
$GPGGA,171423.000,6007.27072,N,01007.48086,E,1,,,,M,,M,,*45
$GPRMC,171423.100,A,6007.27072,N,01007.48084,E,0.08,77.65,010718,,,*1F
$GPGGA,171423.100,6007.27072,N,01007.48084,E,1,,,,M,,M,,*46
$GPRMC,171423.200,A,6007.27073,N,01007.48084,E,0.08,77.65,010718,,,*1D
$GPGGA,171423.200,6007.27073,N,01007.48084,E,1,,,,M,,M,,*44
$GPRMC,171423.300,A,6007.27072,N,01007.48082,E,0.18,77.65,010718,,,*1A
$GPGGA,171423.300,6007.27072,N,01007.48082,E,1,,,,M,,M,,*42
$GPRMC,171423.400,A,6007.27072,N,01007.48080,E,0.06,77.65,010718,,,*10
$GPGGA,171423.400,6007.27072,N,01007.48080,E,1,,,,M,,M,,*47
$GPRMC,171423.500,A,6007.27072,N,01007.48079,E,0.10,77.65,010718,,,*10
$GPGGA,171423.500,6007.27072,N,01007.48079,E,1,,,,M,,M,,*40
$GPRMC,171423.600,A,6007.27072,N,01007.48079,E,0.08,77.65,010718,,,*1A
$GPGGA,171423.600,6007.27072,N,01007.48079,E,1,,,,M,,M,,*43
$GPRMC,171423.700,A,6007.27074,N,01007.48079,E,0.02,77.65,010718,,,*17
$GPGGA,171423.700,6007.27074,N,01007.48079,E,1,,,,M,,M,,*44
$GPRMC,171423.800,A,6007.27075,N,01007.48078,E,0.08,77.65,010718,,,*12
$GPGGA,171423.800,6007.27075,N,01007.48078,E,1,,,,M,,M,,*4B
$GPRMC,171423.900,A,6007.27075,N,01007.48077,E,0.03,77.65,010718,,,*17
$GPGGA,171423.900,6007.27075,N,01007.48077,E,1,,,,M,,M,,*45
$GPRMC,171424.000,A,6007.27076,N,01007.48077,E,0.06,77.65,010718,,,*1F
$GPGGA,171424.000,6007.27076,N,01007.48077,E,1,,,,M,,M,,*48
$GPRMC,171424.100,A,6007.27076,N,01007.48075,E,0.08,77.65,010718,,,*12
$GPGGA,171424.100,6007.27076,N,01007.48075,E,1,,,,M,,M,,*4B
$GPRMC,171424.200,A,6007.27076,N,01007.48075,E,0.06,77.65,010718,,,*1F
$GPGGA,171424.200,6007.27076,N,01007.48075,E,1,,,,M,,M,,*48
$GPRMC,171424.300,A,6007.27076,N,01007.48074,E,0.08,77.65,010718,,,*11
$GPGGA,171424.300,6007.27076,N,01007.48074,E,1,,,,M,,M,,*48
$GPRMC,171424.400,A,6007.27076,N,01007.48073,E,0.07,77.65,010718,,,*1E
$GPGGA,171424.400,6007.27076,N,01007.48073,E,1,,,,M,,M,,*48
$GPRMC,171424.500,A,6007.27077,N,01007.48073,E,0.03,77.65,010718,,,*1A
$GPGGA,171424.500,6007.27077,N,01007.48073,E,1,,,,M,,M,,*48
$GPRMC,171424.600,A,6007.27079,N,01007.48072,E,0.12,77.65,010718,,,*16
$GPGGA,171424.600,6007.27079,N,01007.48072,E,1,,,,M,,M,,*44
$GPRMC,171424.700,A,6007.27078,N,01007.48071,E,0.03,77.65,010718,,,*15
$GPGGA,171424.700,6007.27078,N,01007.48071,E,1,,,,M,,M,,*47
$GPRMC,171424.800,A,6007.27077,N,01007.48070,E,0.09,77.65,010718,,,*1E
$GPGGA,171424.800,6007.27077,N,01007.48070,E,1,,,,M,,M,,*46
Comments
1) RaceChrono should not be able to record GPS data if you output only $GPRMC. RaceChrono requires both $GPGGA and $GPRMC to record GPS data. You probably weren't looking at correct session, as that feed doesn't translate to a session.
2) Export NMEA in RaceChrono generates NMEA from its internal format. It generates both RMC and GGA sentences as in your copy paste.
3) Real output log from device can be recorded by turning on Settings > Expert settings > Save device output. There will be .nmea files inside your session folder and shared .rcz files (which is just renamed .zip). This will be raw output from your device.
It _does_ record when sending only $GPRMC (and $RC2) when connected as "RaceDAC with GPS". I tried it also with RMC+ZDA+VTG, and the position shift remains the same 65 km (I incorrectly wrote 13.8km in previous posts).
(btw: ZDA and VTG messages does not contain any additional info to RMC)
...and I found file: "device_output_100.nmea" contains the correct positions:
(this time with RMC+ZDA+VTG)
$GPRMC,181817.600,A,5967.27087,N,967.48106,E,0.0991,220.13,010718,0.0,E,A*0D
$GPZDA,181817.600,01,07,2018,00,00*5B
$GPVTG,220.13,T,220.13,M,0.0991,0.1836,A*2B
$GPRMC,181817.700,A,5967.27087,N,967.48108,E,0.1069,220.13,010718,0.0,E,A*0D
$GPZDA,181817.700,01,07,2018,00,00*5A
$GPVTG,220.13,T,220.13,M,0.1069,0.1980,A*28
$GPRMC,181817.800,A,5967.27086,N,967.48108,E,0.0739,220.13,010718,0.0,E,A*00
$GPZDA,181817.800,01,07,2018,00,00*55
$GPVTG,220.13,T,220.13,M,0.0739,0.1368,A*27
$GPRMC,181817.900,A,5967.27085,N,967.48108,E,0.0486,220.13,010718,0.0,E,A*05
$GPZDA,181817.900,01,07,2018,00,00*54
$GPVTG,220.13,T,220.13,M,0.0486,0.0900,A*25
$GPRMC,181818.000,A,5967.27085,N,967.48111,E,0.0952,220.13,010718,0.0,E,A*0F
$GPZDA,181818.000,01,07,2018,00,00*52
$GPVTG,220.13,T,220.13,M,0.0952,0.1764,A*2C
Lines with same timestamps from RaceChrono Session Export contains positions 65 km away from here:
$GPRMC,181817.700,A,6007.27087,N,01007.48108,E,0.11,220.13,010718,,,*2B
$GPGGA,181817.700,6007.27087,N,01007.48108,E,1,,,,M,,M,,*4B
$GPRMC,181817.800,A,6007.27086,N,01007.48108,E,0.07,220.13,010718,,,*22
$GPGGA,181817.800,6007.27086,N,01007.48108,E,1,,,,M,,M,,*45
$GPRMC,181817.900,A,6007.27085,N,01007.48108,E,0.05,220.13,010718,,,*22
$GPGGA,181817.900,6007.27085,N,01007.48108,E,1,,,,M,,M,,*47
$GPRMC,181818.000,A,6007.27085,N,01007.48111,E,0.10,220.13,010718,,,*28
$GPGGA,181818.000,6007.27085,N,01007.48111,E,1,,,,M,,M,,*49
Raw input copied from "device_output_100.nmea":
$GPRMC,184952.400,A,5967.27092,N,967.48183,E,0.0972,220.13,010718,0.0,E,A*0E
$GPRMC,184952.500,A,5967.27091,N,967.48184,E,0.0797,220.13,010718,0.0,E,A*0E
$GPRMC,184952.600,A,5967.27092,N,967.48183,E,0.1302,220.13,010718,0.0,E,A*00
Log export, still off by 65 km:
$GPRMC,184952.400,A,6007.27092,N,01007.48183,E,0.10,220.13,010718,,,*2B
$GPGGA,184952.400,6007.27092,N,01007.48183,E,1,,,,M,,M,,*4A
$GPRMC,184952.500,A,6007.27091,N,01007.48184,E,0.08,220.13,010718,,,*27
$GPGGA,184952.500,6007.27091,N,01007.48184,E,1,,,,M,,M,,*4F
$GPRMC,184952.600,A,6007.27092,N,01007.48183,E,0.13,220.13,010718,,,*2A
$GPGGA,184952.600,6007.27092,N,01007.48183,E,1,,,,M,,M,,*48
Please look at the NMEA specification (this is not the official one, but is far most readible one):
http://www.gpsinformation.org/dale/nmea.htm
4807.038,N Latitude 48 deg 07.038' N
01131.000,E Longitude 11 deg 31.000' E
So coordinate formats is DDMM.MMMMM. And your latitude is 5967.27092 which is 59 degrees and 67.27092 minutes. It's an invalid representation of the coordinate, but for RaceChrono it's OK, and it fixes it to 60 degrees and 07.27092 minutes.
So, your stuff, what ever it is, is broken
It could work with only RMC, but I really recommend RMC + GGA or GGA + ZDA + VTG combos. RMC alone or RMC + ZDA + VTG combo do not have fields like altitude.
If I ever said RMC + ZDA + VTG combo is good, then I've must really meant GGA + ZDA + VTG...
I will include GGA later -- I use the altitude only for selecting carburetor nozzle...
ref "Multi-GNSS considerations" in UBX-13003221
I will use $GPRMC and $GPGGA also when the origin data is not GPS.
Combination $GNGGA + $GNZDA + $GNVTG does not work
Argument for including GNxxx:
uBlox M8N will only output $GNxxx when in "multi-sat-nav" mode. I assume this is the same with other multi-sat-nav devices.