GNSS & Cellular Issues - Freematics ONE+ Traccar Edition

Hi everyone,

I recently purchased a Freematics ONE+ Traccar Edition with the internal GNSS module and the SIM7070G cellular modem. I followed the setup guide to install PlatformIO (with VSCode) and flashed the firmware_v5/telelogger using this config.h.

Now I’m facing two issues:

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1. No valid GNSS readings

When I check the logs, I only see output like this:

GNSS:OK(I)
[GNSS] 2025-09-13T22:00:20.400Z
[GNSS] 2025-09-13T22:00:25.200Z

The telemetry data being sent looks like:

[DAT] UCFLVU1M#0:189036,81:-56,24:369,20:0;0;0,82:41*F3

It seems the coordinates are always 0,0. Looking at the code (firmware_v5/telelogger/telelogger.ino), I see that this happens if both lng and lat are 0:

if (gd->lng == 0 && gd->lat == 0) {
  // coordinates not ready
  if (gd->date) {
    Serial.print("[GNSS] ");
    Serial.println(isoTime);
  }
  return false;
}

The strange part is that I did get valid GNSS readings before, but for the last two days (same location) I only get 0,0.

---

2. Cellular connection is unreliable

WiFi works perfectly! it connects and transmits data within ~2 seconds. But when I try using cellular, the connection is very flaky. Most of the time, it fails to log in:

[CELL] Activating...
CELL:SIM7070G
IMEI:865456053704332
[CELL] Searching...
Operator: du
[CELL] IP:100.121.41.147
LOGIN(<myserver>:5071)...
[BUF] 3 samples | 30 bytes | 1/32
[NET] Server timeout
LOGIN(<myserver>:5071)...
[NET] Server timeout
LOGIN(<myserver>:5071)...
[NET] Server timeout

It only succeeds maybe 1 out of 50-60 times, even though WiFi works fine to the same server.

---

Questions:

1. Why might the GNSS module be stuck at 0,0 after previously working? Could it be a hardware, antenna, or firmware issue?
2. Any suggestions on improving the SIM7070G connection reliability to the server (Traccar on port 5071)?

Thanks in advance!

1. Are you sure it has a good GPS signal? I think lack of GPS signal is the most likely, but obviously it could any of the above.
2. Do you see anything in the server logs when it tries to connect?

Thanks for the quick reply!

1. Yes I'm pretty sure, I kept it outside of my window to test and I get the same issue.
2. Nope, the logs are empty I mostly use tcpdump to see if my device hits 5071 or other port in any way. But the only time it happens consistently is when I connect over WiFi.

I left the device powered on overnight, cellular seems to have been stable after like 20-30 minutes or so and then had been stable ever since (which is almost 12 hours now), and I can also see GNSS in the logs, but it took a good 2 hours to get a fix. Is this normal? My device is indoors but is not too obstructed, I sit right next to a window.

It could be normal. Initial fix can be slow because it needs to download satellite paths. And indoors probably makes it slower.