DevTimeReq supported by RAK7258 integrated lora server?

Is the MAC command DevTimeReq supported by the integrated Lora server of RAK7258?

If yes: what time source is used? NTP via the uplink connection?
If no: could you please upgrade lora server to current chirpstack version?

@yutao will give you the best answer of this.

DevTimeReq will be supported in the next release. The release time will probably be in late March. If you want to use it soon, I can provide you with a beta version.
On a GPS-enabled gateway, the time is synchronized via GPS. Otherwise, synchronization will be performed via NTP.

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Great!
Yes, i would like to test the beta.

@yutao

Hi!
Meanwhile i connected a Quectel L96 GPS module to UART_RXD1/TXD1 of RAK634 module inside of the RAK7258 gateway. The L96 is based on Mediatek M3339 chipset, so the same as L70. It has the full PMTK command set.

The RAK7258 is running 1.1.0062_Beta_02 rmaster-884aa39

I checked with logic analyzer on the UART connection and see the PMTK commands after powering on the gateway, and after a while the GPRMC strings every second.

But it seems the packet forwarder does not resolve those:

Mon Mar 16 14:35:58 2020 user.info lora_pkt_fwd[1592]: WARNING: [gps] could not get GPS time from GPS
Mon Mar 16 14:35:59 2020 user.info lora_pkt_fwd[1592]: WARNING: [gps] could not get GPS time from GPS
Mon Mar 16 14:36:00 2020 user.info lora_pkt_fwd[1592]: WARNING: [gps] could not get GPS time from GPS
Mon Mar 16 14:36:01 2020 user.info lora_pkt_fwd[1592]: WARNING: [gps] could not get GPS time from GPS
Mon Mar 16 14:36:02 2020 user.info lora_pkt_fwd[1592]: WARNING: [gps] could not get GPS time from GPS

The log entries repeat exactly every 1,0 second. So it seems this is triggered by GPS NMEA sentence, but for some reason the time is not resolved from it.

Any idea what’s going wrong here?

I stopped the packet forwarder and checked data on /dev/ttyS1. I see the incoming NMEA sentences. It seems the GPS has no fix, so no valid time -> this explains why it does not work.

Need to check why it does not get a fix.

$GPRMC,002429.109,V,0.00,0.00,060180,N,V*3D
$GPGGA,002429.109,0,0,M,M,4D
$PMTKLSC,18,0,18
42

$GPRMC,002430.109,V,0.00,0.00,060180,N,V*35
$GPGGA,002430.109,0,0,M,M,45
$PMTKLSC,18,0,18
42

Have you installed the GPS antenna correctly? It can be seen from the NEMA message that the GPS module has not obtained the position information. This is usually caused by a weak signal. If you are testing indoors, you need a GPS signal repeater to introduce GPS signals indoors.