Problem with reading NMEA 0183 from N2K gateway ONWA KC-2W

[Baikal]

There is an N2K network with a Lowrance POINT-1 GNSS receiver with a connected nmea0183 - N2K converter with built-in WiFi. I transmit data to CPN via an Ethernet TCP connection.

https://onwamarine.com/kc-2w/

The location is not updated, COG and SOG work, GPS Status does not work.
I checked in another program and the coordinates are updated there.
The coordinates are updated in the NMEA log.

I recorded a video and nmea log where I moved the GPS receiver to the window and moved it closer to it

VIDEO
https://www.dropbox.com/scl/fi/wfd0s...=gp0nea70&dl=0

NMEA LOG
https://www.dropbox.com/scl/fi/n21pg...=d4vopuhn&dl=0

[stevead]

An entry from your log:

$GPGLL,5216.8286,N,10419.8796,E,,V,N*56

The last two fields 'V' and 'N' indicate "data invalid" and "no valid fix" respectively.

So not surprising that OpenCPN is not reporting a valid position.

Either you really do not have a valid fix or the gateway device is not faithfully converting the NMEA 2000 messages to the equivalent NMEA 0183 sentences.

[PippaB]

$GPGLL,5216.8347,N,10419.8833,E,,V,N*5A
$GPGGA,,5216.8347,N,10419.8833,E,,,,,M,,M,,0000*68
$GPRMC,100238.00,V,5216.8347,N,10419.8833,E,0.1,255.1,110924,87.0,N*7B
$GPVTG,255.1,T,,M,0.1,N,0.1,K,A*0E
$GPZDA,100238.09,11,09,2024,,*6A

+1 on stevead's comment. Both your GLL and RMC sentences are indicating no valid fix and mode indicator of no valid data.

You might get OpenCPN to display your position if you turn off GLL and GMC, the position indication is also in GGA, but the quality field is left empty. Since a '0' there = bad quality I don't know what OpenCPN will do with it being blank (if it assumes a zero for a missing value then you are in the same boat).

This reference I find to be pretty good at clear NMEA 0183 documentation.

[barnakiel]

Programs may handle the optional fields differently.


Test the receiver by plugging it into a N2K network.


A faulty n183 can be fixed up on the fly, but I would not go this way.


Perhaps you did not give enough time for the receiver to get a fix. This happens with cold receivers, long stored receivers, and especially indoor. So try giving it some extra time. Plug in, go get a coffee and see if it helps.



gl


b.

[Baikal]

Thanks to everyone for the answers!
I suspected that the problem was the lack of satellite signal strength status and apparently CPN is configured to receive FIX status to start working.
I also associate this problem with cyclical location losses with CPN-connected AIS transponders, where there is also a lack of GPS status, and again, other programs do not have this problem.

Question to the developers: Is it possible to add ignoring satellite signal quality to nmea0183 processing to allow location updates?

[stevead]

Without seeing the original NMEA 2000 messages it is impossible to determine whether you genuinely do not have a valid fix or whether your gateway is incorrectly performing the conversion.

Until that is determined it would be premature to consider any changes.

My response to your proposal is not fit to print, but as I am not a developer....