I have mountain property that ranges from 10,000' to 12,400' that I really need to fly over for several reasons. Flying it continuously uphill is completely impossible as the AC collision avoidance system will kick in to avoid colliding with the ground, in some cases within 200' horizontal distance.
The alternative in this case is climbing to each point at the next 400' elevation gain above sea level and flying the next 400' ascent. 400' AGL provides the field of view I need, so climbing to the top of the property and flying downhill is about the only option. Maintaining anything close to 400' AGL would be conjecture at best. Visually estimating altitude above ground line from a point above is nearly impossible from a technical standpoint. Calculating altitude based on aircraft position and contour lines on a map corresponding to the app location on my tablet screen would consume most of the limited flight time available from each battery.
I could just wing it, try to stay within the 400' limit, but it's much easier to comply with regulations than to defend your rationalization why you didn't comply, so the enigma is wrapped in a conundrum wrapped in a flour tortilla. In some areas I can literally gain 800' altitude by moving 25'.
If I want to publish the video or photos from my reconnaissance of this historic area (which was my original plan) and do it without fear of being found in violation, it will take literally months rather than a single day. Comply or violate? There really isn't a choice, it's compliance.
I have tried to source a number of distance detector/ ranging devices that would be appropriate for UAVs similar to the
MA. Weight is a factor- sensors that can measure to 330' weigh about 4 ounces or more. I've found dopler sensors that weigh in at just over an ounce, but transmitting the data and integrating it into the DJI app or developing another app is a challenge and adds significant weight. In addition, the distance with the smallest doppler units in a size suitable for a UAV is limited to less than 100 feet.
While a lot of us would love to have the AC maintain 400' AGL over contours, I doubt it is an adequate market size to justify development of a light weight add on. But who knows, there a lot of talented and creative people out there.