I have recently started using Litchi to fly waypoint-based photogrammetry flights with a DJI Phantom 4 Pro. The routes were created in DJI Flight Planner, then edited, uploaded, and executed in the field using Litchi. The photos collected on these flights will be used to create aerial photo mosaics and high-resolution DEMs.
However, I’ve encountered an unexpected problem. Every flight so far has a number of waypoints where photos were not collected by the drone. The location of these missed photos varies between routes, and appears to be random. For example, in the photogrammetry route below, a photo was not collected at Waypoint 39 the first flight. The second time I flew the exact same route, photos were not collected at Waypoints 5, 6, and 14.
A different route with 99 waypoints in another location ended up with 9 missing photos. Other users have encountered similar issues, but I can’t seem to find any suggestions on what might fix the problem.
Does Litchi (or the Phantom 4 itself) have some sort of built in tolerance or distance threshold beyond which it will not take a photo? In other words, if the drone is too far from a waypoint once it reaches that point in the route, will it skip that photo? For example, if the drone reaches a waypoint and then a gust of wind blows it to one side could that cause it to skip a photo? This is just a guess, as the 99-waypoint route that missed more photos was flown on a windier day.