I’m currently assessing possibilities for connecting an RTK service to my drone and I also found descriptions of example setups, e.g. here.
Now the thing is, that I’m entering a pre-existing RTK setup and I (and the RTK owner problably too) would like to make as little changes to this setup as possible. Plugging a computer with Mission planner into the base station or exposing the corrections as NTRIP wouldn’t be my first choice. Ideally, every change would take place on the drone.
Currently, I have the information that RTK users receive corrections via telemetry modems of type Satelline-3ASd which work in the 869mHz band. Could I just buy any 868 telemetry modem, e.g. this or this, connect it to a free telemetry port, set the sender data the RTK owner will tell me and receive corrections? And how would I configure this connection?
It’s worth noting that the drone has a Raspberry Pi 4 with LTE onboard. So, if there is any setup including e.g. Mavproxy, that could be realized too.
No, you can’t just grab any old radio modem and expect it to work. You need one that is compatible with the Satel modem standard/protocol, which I don’t see published anywhere. So, you probably ought to just get the same radio modem as is already in use on the network and configure it for serial output to your companion computer or autopilot itself.
So a specific 868 modem only communicates with specific other modems in a proprietary fashion? That surprises me. I thought there was a kind of de facto transmission standard, at least for general purpose modems like the one I mentioned.
The problem with the Satelline-3AS is that it measures 137x67x29 mm and weights 260 grams, not counting antenna and cabling. It ‘should’ be possible for my drone, but, you know, the lesser the better.
There are established standards, but you need to do the research as to what protocols are used before just buying something that works on the same or similar frequency and assuming it will communicate.
For example, you can’t expect a 2.4GHz WiFi router to be able to meaningfully connect with a 2.4GHz RC receiver just because they operate in the same frequency spectrum.