OpenHD vs XBee

OpenHD

• Can consolidate the telemetry and video into one link (could also put the “backup” manual controls onto this one comm link but it's good to have a fail-safe so we probably will not do this)

• More of a “plug n’ play” option when compared to the XBee option

• OpenHD hardware

  • 2 RPi’s – one for the ground pi and one on the plane

  • 2 WIFI adapters (minimum)

  • List of supported WIFI adapters: WiFi Adapters | OpenHD

  • OpenHD says you can use 2 WIFI adapters on the ground for “diversity”, which improves signal reception

  • Diversity is a way to improve the reliability and quality of video reception.

    • If you connect 2 or more WIFI adapters to the ground pi, whichever adapter is currently receiving the best signal will be used.

    • Can connect different kinds of antennas to the 2+ WIFI adapters, such as a directional antenna and an omnidirectional antenna. This allows for automatic switching from long range to short range, so that you don't have to keep your directional antenna pointed toward the UAV when it is nearby.

  • Requires RPi and WIFI adapter on plane and thus will be harder to fit. Mechanical has said there shouldn’t be any issues with fitting it though.

XBee

• XBee option would be more involved than OpenHD

  • Need a breakout board to interface with the RF module. They sell different boards that come with a RS-232 port or USB port for example.

    • https://www.robotshop.com/ca/en/xbee-serial.html

• Does not perform well with video transmission (due to data transmission limits), so would only be for the telemetry. This would require us to find some other video transmission solution like the DJI Lightbridge

• XBee Hardware

  • 2 XBee RF module (one for ground station, one for plane)

  • Board to interface with the XBee module

  • Smaller overall size than the OpenHD system – easier to fit in airframe