Reliable communication is important for us to provide real-time and accurate information of the surroundings to the pilot. We considered a lot of COTS communication radios which are used by the FPV community for transmitting video over long range. There were a few problems with them which are stated below:
- But all these modules require a receiver in the aerial vehicle (which would add weight).
- Also a lot of these radios transmit analog or digital video but the data is transmitted via serial protocol. This was a problem for us as the only way to establish connection between Epson (AR headset aka user system) and Jetson is via wifi.
- These might cause interference with the DJI radio.
After considering these issues, we decided to stick to wifi based communication. During the Fall Validation Experiment (FVE), we faced a lot of issues with wifi communication. After testing we established the reason for these problems to the interference caused by DJI radio which operates at the same frequency of 2.4Ghz. To fix that issue we decided to operate at 5Ghz which had another benefit in that it allowed more bandwidth to transmit video.
We selected Unifi AC-M wifi router along with UMA-D directional antenna considering:
- Possibility of attaching a directional patch antenna.
- Transmission power greater than 20 dBm.
- Supports the wifi protocol available in Jetson TX2 wifi module and Epson wifi module.