Re: [gpsd-users] Getting data from U-Blox 6 receiver (native or NMEA protocol)

[Sander Smeenk]

Quoting Askar Ibragimov (address@hidden):

> address@hidden ~]# stty -F /dev/ttyUSB0 ispeed 57600
> address@hidden ~]# cat /dev/ttyUSB0
> $GPGGA,191318.00,6013.99474,N,02443.49081,E,1,07,1.38,43.2,M,17.8,M,,*6F
> $GPGLL,6013.99474,N,02443.49081,E,191318.00,A,A*6C
> $GPGSA,A,3,29,02,31,21,05,20,16,,,,,,2.90,1.38,2.55*09
> $GPGSV,2,1,07,02,14,053,29,05,33,077,45,16,20,306,26,20,28,053,40*7D
> $GPGSV,2,2,07,21,43,198,36,29,64,100,43,31,27,235,33*43
> $GPRMC,191318.00,A,6013.99474,N,02443.49081,E,0.093,,210415,,,A*7C
> $GPVTG,,T,,M,0.093,N,0.173,K,A*2C
> $GPZDA,191318.00,21,04,2015,00,00*64
> ^C

I was reading up on this thread and noticed the conclusion of 'bad
hardware' and beg to differ. ;) As you show above, the USB-serial Ublox
gives seemingly perfectly sane NMEA output.

Reading your log, it looks like gpsd is having trouble getting the port
settings right:

| gpsd:INFO: opening GPS data source type 3 at '/dev/ttyUSB0'
| gpsd:INFO: speed 57600, 8N1
| gpsd:IO: => GPS: 5053474700c100010000000050924746
| gpsd:INFO: speed 57600, 8N1
| gpsd:INFO: gpsd_activate(2): activated GPS (fd 7)
| gpsd:CLIENT: => client(0): 
<snip>"path":"/dev/ttyUSB0"<snip>,"bps":57600,"parity":"N","stopbits":1

Looks okay, but then,

| gpsd:INFO: speed 4800, 8N1
| gpsd:INFO: speed 9600, 8N1
| gpsd:INFO: speed 19200, 8N1
| gpsd:INFO: speed 38400, 8N1
| gpsd:INFO: speed 57600, 8N1
| gpsd:INFO: speed 115200, 8N1
| gpsd:INFO: speed 230400, 8N1
| gpsd:INFO: speed 230400, 7N2
| gpsd:INFO: speed 4800, 7N2
| gpsd:INFO: speed 9600, 7N2
| gpsd:INFO: speed 19200, 7N2
| gpsd:INFO: speed 38400, 7N2

What is all this speed / parity flipping?

| gpsd:DATA: packet with bad checksum from /dev/ttyUSB0
| gpsd:PROG: switching to match packet type 1: @,address@hidden
| gpsd:PROG: switch_driver(NMEA0183) called...
| gpsd:PROG: selecting NMEA0183 driver...
| gpsd:INFO: /dev/ttyUSB0 identified as type NMEA0183, 138.857988 sec @ 38400bps

Again, if gpsd is reading that port at 38400,7n2(!) while the other
end is yelling at 57600,8n1 i would expect such mangled input.

Your 'cat /dev/ttyUSB0'-example shows gpsd should at least be able to
read those 'clean' sentences as shown in your terminal.


But it was good to read you got it working none the less. If time/pps
accuracy is what you're after, you'll prefer true serial over usb-serial
anyways. ;)

-Sndr.
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