Close range radar is crude and probably will cause a lot of aggravation with too many false positives. Like other people have mentioned, how close it too close? What is the UAV supposed to do if it does detect an obstacle in it's path --- ascend, stop and hover, go left or right? ****, I get a headache just thinking of the options.
I think the future will involve a combination of current technology such as LIDAR and facial recognition software. Just imagine your Phantom flying along at max. speed as you're casually chatting with a friend and not paying attention to the bird. The Phantom's LIDAR and recognition software detects a mighty 100-foot oak directly ahead of it's flight path. As it nears critical perimeter, the flight computer automatically instructs the Phantom to ascend to 150 ft. while reducing airspeed somewhat so it can clearly avoid hitting the tree. Easy peezy, lemon squeezy --- and you can continue engaging in idle chatter and being a lazy pilot.
The technology already exists, just takes some ingenuity to make it work on a cheap drone. I'm not sure how small LIDAR can get but I would imagine it could shrink down to a few ounces eventually.
:mrgreen: