Gnss position not uploaded to chirpstack through concentratord with kerlink gateway

Hi,

I use concentratord and mqtt forwarder on a kerlink istation gateway with keros 5.

Concentratord works perfectly (although intended for the ifemtocell model) however, the gnss positioning does not go back to chirpstack.

I tried several settings of the concentratord.toml file but I can’t get the gps to go back.
Is this a bug or is it not functional at all for this hardware?

hardware the gateway has a gps chip. The nmea frames are accessible here /dev/nmea1 ( and 2 3 )

tested settings :

/etc/chirpstack-concentratord/concentratord.toml

[gateway]
region = "EU868"
model = "kerlink_ifemtocell"
model_flags = ["GNSS"]

try to change:

gnss_dev_path="/dev/gps0"

or

gnss_dev_path="/dev/nmea1"

but not work

Static location work perfectly on concentratord.toml

example of cat /dev/nmea1 :
( location manualy modified for privacy )

$GPGGA,123635.00,4518.80329,N,00404.20947,E,1,08,1.11,116.5,M,46.7,M,,*5E
$GPGGA,123724.00,4518.80342,N,00404.20910,E,1,09,0.87,115.1,M,46.7,M,,*58
$GPZDA,123724.00,25,01,2025,00,00*64
$GPRMC,123725.00,A,4518.80341,N,00404.20910,E,0.019,,250125,,,A*78
$GPGGA,123725.00,4518.80341,N,00404.20910,E,1,09,0.87,115.1,M,46.7,M,,*5A
$GPZDA,123725.00,25,01,2025,00,00*65

Are there other leads that could help me?

gateway package versions :

chirpstack-concentratord - 4.4.6-r1
chirpstack-mqtt-forwarder - 4.3.1-r1
keros - 5.11.0-0-g38de666d