GPS Receiver - NMEA location debugging

General
1

The BR1 Mini 5G does not have it’s own GPS antenna. To substitute, I have NMEA 0183 data being sent over UDP from a reliable NMEA datasource, I can capture this on the network.

tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on enp6s18, link-type EN10MB (Ethernet), snapshot length 262144 bytes
11:09:23.944093 IP 192.168.50.11.46055 > 192.168.50.255.2000: UDP, length 37
E..A$.@[email protected].$GPGLL,3358.0076,N,08419.4238,W,,A*3D
11:09:24.158410 IP 192.168.50.11.46055 > 192.168.50.255.2000: UDP, length 37
E..A$$@[email protected].$GPGLL,3358.0076,N,08419.4247,W,,A*35
11:09:24.158544 IP 192.168.50.11.46055 > 192.168.50.255.2000: UDP, length 15
E..+$%@[email protected].........$IIZDA,,,,,,*5F...
11:09:24.943273 IP 192.168.50.11.46055 > 192.168.50.255.2000: UDP, length 37
E..A$a@.@./...2...2......-_.$GPGLL,3358.0074,N,08419.4247,W,,A*37
11:09:25.155667 IP 192.168.50.11.46055 > 192.168.50.255.2000: UDP, length 37
E..A$n@.@./...2...2......-_.$GPGLL,3358.0074,N,08419.4247,W,,A*37

I have my Peplink MAX BR1 Mini 5G configured to receive GPS using

image
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However I do not see any sign of GPS data, nor any logging nor status information.

I tried the Peplink API for info.location and received

{
    "stat": "ok",
    "response": {
        "gps": false
    }
}

Can anyone suggest troubleshooting steps on how to configure the GPS Receiver?

Thank you.

2

You haven’t entered the sender’s address in Access Control. Also, if that doesn’t fix it, it’s being sent to the broadcast address, not sure if the BR1 will like that - try with its unicast address.

3

Yes, it was going to the broadcast address. Thanks for the suggestion.

I’ve updated the access control :

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And the sending config to use the Peplink IP Addr: (Signal-K)

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image820×697 22.7 KB

Annoying that I can’t see any debug or activity through the Peplink UI. Is there any logging capability on the peplink? I can’t capture the UDP from my other devices anymore since it isn’t Broadcasting…

I’m still getting “False” from the API and a very stale (starlink) location is shown in InControl.

4

For units with internal GPS, the NMEA sentence stream is duplicated on port 60660. Open a raw TCP port to that to see if it shows anything. PuTTY will do that.

5

I am not able to connect on 60660.

I can view it using Nmap, but can’t connect using NC. I’ll mention I’m not a networking expert.

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6

Are you sending the right strings? I would expect GGA strings for positioning.

GGL is indeed also a proper format, but with GGA I don’t have problems receiving the position in InControl. Maybe a bug in the Peplink software? I know initially, I had the same issue using an older Trimble GNSS sending slightly different strings, where a fix in the firmware was made by the Peplink team to also correctly process these strings.

7

I see you’re using GP prefix instead of GN or GA ones. That might be the issue, requiring a fix in the firmware. Maybe you should open a ticket, or try to emit GA or GN prefixes.

8

I don’t have sufficient data for a GGA message, but I don’t see why GGL wouldn’t work.

On a whim I asked Google what is the best message to send, Gemini is suggesting GPRMC ** Provides recommended minimum specific GPS/Transit data, including time, date, latitude, longitude, and speed.

So now I’ve started sending GPRMC per the gemini recomendation

$GPRMC,A,3358.0174,N,08419.4179,W,0.2,146.0,5.7,W*75

Still no sign of location in peplink. Or any error messages…

Interesting. Tons of learning for me, but these prefixes are :
GA: Galileo
GB: BeiDou
GP: GPS
GL: GLONASS. When more than one constellation is used.
GN: Combined GNSS position, for example, GPS and GLONASS.
GQ: QZSS

I don’t think I have any control over the Prefixes.

I’m chaining a number of systems together here:

  1. Cheap “MGears” USB dongle from Amazon (Amazon.com: Mgears USB GPS Receiver Antenna for Navigation Laptop PC Car Marine (USB A-Type) : Electronics)
  2. Victron Cerbo GX running Signal-K
  3. Peplink Mini.

Curious if anyone has a better approach.

I will try opening a support ticket.