Tuxer

Bidirectional path tracing. You send rays from the sun, rays from the camera, and try to connect them. The ones that connect are the ones that get computed for illumination.

The no flight under 500 ft over anything other than sparsely populated areas is in AGL, not MSL. I assume they would also need to stay out of class D/C/B areas. My main concern is that this doesn't take care of helicopter traffic that doesn't have this 500ft AGL rule.

Having ADS/B or a variant of it for the drones would take care of that issue, as in 2020 every aircraft will require ADS/B.

Honestly, that's not entirely true, and not very respectful to the pilots in that crash.

AF447 was caused (partially) by the pilot's misunderstanding that holding the control stick all the way back was gonna make the aircraft go up at the best rate of climb, and not put the control surfaces all the way back.

The AP (autopilot) was off for quite some time when the crash happened. What was supposed to be on though, as always, is the Airbus Fly-by-wire system in normal law, that is in between the pilot's controls and the actual commands sent to the control surfaces (ailerons, elevators...). This system was off (in it's direct control law, more precisely) due to the pitot tubes sending non accurate data, because of the icing problem. The pilot didn't notice that.