Re: [Question] gpsd, ntrip & C94-M8P (u-Blox)

[Florian Kiera]

Hey Gary!

Thanks to Greg I am now able again to use gpsd to receive the correction data from my NTRIP Caster. (the NTRIP Caster stream is good again!)

To give a short explanation how I solved my issue before:
Greg gave me a huge hint to check out net_ntrip.c line 453. (You might already know:) In this line it checks the "ICY 200 OK" feedback. However, because my caster sends "ICY 200 OK\x0d\x0a" gpsd counted it as error and closed the connection. I just changed net_ntrip.c line 33 '#define  NTRIP_ICY "ICY 200 OK"' to "ICY 200 OK\x0d\x0a", installed it anew and now the "good stream" works again.

Later I will try to change it on the ntrip casters side to not run a "custom ugly solved" gpsd.

Even the receiving part somehow works now. The receivers computer seems to be the unstable thing here. After some time and odd outputs in dmesg, it kicks and adds the receiver to a new port address (ttyACM1 cause ttyACM0 is still used by gpsd) which, of cause, gpsd cannot find dynamically. That for gpsd gave out the error:

gpsd:ERROR: Write to RTCM sink failed, type u-blox
gpsd:ERROR: SER: device open of /dev/ttyACM0 failed: No such file or directory - retrying read-only
gpsd:ERROR: SER: read-only device open of /dev/ttyACM0 failed: No such file or directory
gpsd:ERROR: /dev/ttyACM0: device activation failed.
gpsd:ERROR: /dev/ttyACM0: activation failed, freeing device

DMESG Output:

[10994.628969] usb usb3-port1: disabled by hub (EMI?), re-enabling...
[10994.628982] usb 3-1: USB disconnect, device number 2
[10994.629269] cdc_acm 3-1:1.0: failed to set dtr/rts
[10994.916565] usb 3-1: new full-speed USB device number 3 using xhci_hcd
[10995.046583] usb 3-1: device descriptor read/64, error -71
[10995.283281] usb 3-1: device descriptor read/64, error -71
[10995.513216] usb 3-1: new full-speed USB device number 4 using xhci_hcd
[10995.669450] usb 3-1: New USB device found, idVendor=1546, idProduct=01a8, bcdDevice= 3.01
[10995.669454] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[10995.669457] usb 3-1: Product: u-blox GNSS receiver
[10995.669459] usb 3-1: Manufacturer: u-blox AG - www.u-blox.com
[10995.716557] cdc_acm 3-1:1.0: ttyACM1: USB ACM device

So it all didnt worked due to the odd output "ICY 200 OK\x0d\x0a" (the hexadecimal "ok" is odd) the ntrip caster made and the computer being corrupted or something along those lines.
I cannot tell why it didn't worked before all this but at least I got it to work NOW.

So the only thing I need to have a look at is the ntrip's caster odd hexadecimal numbers and it should all work now.

Thanks Greg and Gary. I've learnt a lot about gpsd and UBX besides causing all this trouble/weirdness.

As always the solution must've been that simple... UGH. Thank you for your patience and tips!

Regards Florian

P.S. I only used "gpsd -G ntrip://usr:pw@ip:port/STREAM" to test if gpsd is able to open a stream to my caster. That gpsd lacks a receiver here in this command is clear. It just had testing purpose (learning gpsd in small steps) and didn't unnecessarily spammed me with the receivers NMEA/TPV output.