We did it back in the day, using text messages (see here for one example). Other people have tried it more recently with 3G. In general, it's not optimal, due to phone->plane interface issues, rapidly changing OS and phone hardware and general problems that come with using hardware that wasn't designed for the job.
Also, we never go beyond a mile or two in our work, so the usual short range RF is fine. But it's certainly an option for longer range. Might be better to use embedded electronics with a 3G radio/simcard module than an actual phone, but the idea can work.
It's possible only if your drone has an AI reliable enough that it can operate safely without realtime command uplink. Even a 3G modem will still drop from time to time, bringing latencies to 10 seconds or more. That's the engineering part.
The other part is more important: the law. If you're expecting your link to be unreliable so much that you wouldn't be able to intervene at any point in time you're violating the man-in-the-loop rule. And risking ugly damage and injuries.
Replies
to add to this question, what would be needed for 50 mile radius?
Actually the rest of their website is also worth a glance: http://www.smartskies.com.au/
Andrew
Also, we never go beyond a mile or two in our work, so the usual short range RF is fine. But it's certainly an option for longer range. Might be better to use embedded electronics with a 3G radio/simcard module than an actual phone, but the idea can work.
The other part is more important: the law. If you're expecting your link to be unreliable so much that you wouldn't be able to intervene at any point in time you're violating the man-in-the-loop rule. And risking ugly damage and injuries.