Hello,
So I want to use a multipoint to point communication to send three different protocols, telemetry, gps corrections and rc commands, to a single hardware in my drone. Said hardware must separate the three protocols and send them to right devices.
I was thinking that I need a companion computer for this,I don’t have much experience. So my question, how can I achieve this?
You can do all that with a RDF-900 telemetry modem with the https://www.getfpv.com/rfdesign-rfd900-tx-mod-rc-transmitter-module.html TX mod
Hello,
could you explain this product a little better? I didn’t understand how it could be a intermediary between the ground station, gps and the drone
Other than buying this product, is there a way to do what I said using a sbc, like raspberry pi?
There are multiple ways to do what you want. A GCS software like Missionplanner supports mavlink telemetry (obviously), RC control and RTK inject (I have no experience with that). It all uses the mavlink protocol. How you get the mavlink data to your vehicle is depending on what you need regarding price, range, perhaps video downlink, etc.
I use regular wifi on my rovers for RC control (sometimes), telemetry and video. With Alfa adapters connected to a companion computer and the GCS (GCS has directional antennas), I get 200m to 300m range. This depends on the weather, obstacles and other wifis in the area. 300m is plenty for a rover. A copter up high and out of the fresnel zone might achive more range. If you are allowed to use the 5GHz band and more TX power in your country, you will have even more range.
With the RFD900 mentioned above, you will have a range of several kilometers, but no video downlink.
The RFD900 comes in different versions. The one above plugs into a RC transmitter and forwards the telemetry via wifi to the GCS. There are also versions, which are plugged into the GCS computer via USB. And you will have to buy the vehicle side RFD900, too. Here is the RFD900 TXmod bundle:
Hello, thank you for the answer.
I should have explained a little better, my apologies. I want to build this system using a sbc, the problem it’s that I am ignorant in matters related to communications and message protocols.
At the user’s end, the sbc should gather the signal gps, rc and send them while also receiving mavlink through the same rf link at the same time.
At the other end the sbc should receive the rc and gps while also sending mavlink.
The user’s sbc should direct the mavlink while the end’s sbc should direct the gps and rc to the right ports.
This module that was sent won’t work because I will build the system practically from scratch. I am having difficulties find the theory to make this possible. About why I am doing from scratch, which I agree it’s gonna be a lot of work, to see if I can do it and to learn.
I stand by my answer. With the RFD900 you do not need any SBC on the vehicle, and just need a SBC on the ground
another question:
Is there a way to mix rc, mavlink and gps signals into a single signal, so I can use just one antenna to avoid interference, and at the receiver end, it sorts the signal into individual ones and them direct them?
Yes, that is what RFD 900 does for you.
ok,thank you @amilcarlucas, I was asking for other ways because this product is not certificated in my country, so I was trying to find other alternatives, but I found the rfd900x it’s certificated.
Just a question, I see it can have two antennas, for me to use rc and telemetry I need to use both? Sorry if it is a noob question, I am worried about other devices getting interference.
I am also using a xbee to transmit rtk corrections from a base away from the gcs to the drone, and the drone has two rtk antennas, so before of buying, I needed to know about the interferences.
Here we use RFX868x, works great, rfd900x is not permmited here either. It has two antennas for diversity. Google for “antenna diversity” to find out what that is.
All the signals with use both antennas either at 868MHz or 900MHz depending on the version you use.
You will no longer need the Xbee. RTK corrections, telemetry and RC controls will all travel over the same frequency. Please read the instructions manuals of the radios, you will no longer be a noob then.
Hello,thank you for putting up with my questions. So to use rc and telemetry I need the tx mod or can I just use 2 rdf-900 telemetry modem? Seems like the tx mod is not permitted here yet
But if the txmod has just a 900x inside, it maybe be permitted
You need the TXMOD in order to send RC signals. If you only need telemetry and RTCM RTK corrections then you can use 2 RFD-900
Here in my country only the rfd900x is permitted, not the txmod, so seems like I am going to seach for other alternatives