Uplink

At present, the only uplink we have consist in the radio control transmitter. It is used for flight control in manual and assisted flight modes, but also for all sort of interactions like flight mode switching, gain and parameters setting, missions event, waypoint displacement. This "switch and sliders" exercise is simplified by the real time feedback on the ground station which can be talked by the festival speech synthesizer for single person operation. This is probably not the most efficient way to communicate with an UAV, but this is cheap and widely available. We intend to keep supporting this solution even when we have others available.

Downlink

As explained in the controller page, the data downlink is done in the audio channel of the 2.4GHz video transmitter. We achieve 4800bps using a pair of cmx469 FSK modem chips or 1200bps using an airborne cmx and a soundcard-software modem on the ground.

Radio modems

We are evaluating a networked radio modem solution. These tiny (10g) Coronis Wavecards operate in the 868MHz ISM band at 500mW. Line of sight range are expected up to 5 km with throughput up to 19.2kbps.