RAK7205 GPS Not Changing

Issue: RAK7205 GPS Not Changing


Server: TTN

Details: I provisioned the RAK7205 and placed it on the dashboard of my car. It sends a LoRa Packet every 30 seconds which get captured by the gateways and forwarded to TTN. I have 2 gateways, one on rooftop at home and one at the office. When traveling between home and work the packets are missed in the “dead zone” between home and work. When back in range, the packets are captured and forwarded. It all appears to be working.

But here is the problem: The GPS Coordinates never change. At home, at work or whenever in range, the RAK7205 always reports the same GPS Coordinates. The other parameters like time, temp, humidity, barometer all vary as expected, but longitude, latitude and altitude always stay the same.

Any help would be appreciated.

Assuming it has the GPS antenna in clear view of the sky - can you try it outside connected to a laptop to see if what it says it is doing.

I opened the RAK7205 an found the location of the GPS Antenna and re-assembled it. Now, the GPS Antenna surface is pointing up through the windshield, it seems to be working. I guess the antenna has so little gain, that orientation really matters. Some more surface area for the antenna would help. Also, IMHO, if the RAK7205 is not getting a reading, it should not send GPS data at all.


It doesn’t transmit GPS co-ordinates (which was another forum query the other day as it happens) if it has no GPS signal. But if it is getting enough to try to hear the ephemeris it may well send the last known co-ordinates. The small ceramic antenna aren’t great at getting a first fix - once the GPS chip knows what to listen for (the ephemeris), they are usually OK.

I spun mine up and the serial output does tell you what’s going on, so you may find that info useful in the future.

As to functionality like send/no-send, I’d prefer a status flag and hdop to be included, but some others won’t. You could use the RUI tool to create your own firmware. Or if you have a specific use case & volume of units, the RAK team could create some custom firmware for you.