![]() ![]() I took off 3m above ground level and so had the mission fly at 22m. So that I can understand Dave’s comments, are we saying the drone has literally dropped 5m out of the sky from beginning to fly a DD mission to the end? It was set to fly at 25m above the flat ground level. If I were to convince my employer to purchase further equipment to help the software correct the rise in pressure or drop in altitude of the drone, paying an additional $49 per map is out of the question. As previously expressed, it is critical for me that I am able to carry out this initial survey without any further equipment. ![]() This issue more or less makes the elevational side of DD redundant for me, leaving just an orthomosaic export. I am very concerned that a height difference of 5m has been recorded by DD when in fact there should be nil. I suggest JamesC re-fly the mission on an overcast day with low wind at a low speed at 300’ altitude and compare those results.ĭoes the P4P gradually warm on sunny days and cause a barometer drift that causes an altitude drift? But the barometer change was still small, in the 0.001" range. And the poor results consistently happen on missions flown when the sun is out, like the mission shown by JamesC. This error consistently shows a rise from South to North. That being said, poor results have also occurred with 1 m elevation error over the 150’ distance. The barometer recording for this mission showed less than 0.002" change. Its barometer-based altitude control can work well with only 1’ Z error in the total RMSE of 6.2’ reported by DroneDeploy. So a P4P can produce DD maps with very good relative elevation results. This should be in the worst-case direction for showing the type of error you see since the mission starts from the South and then zig-zags it way North. The results of my missions of the same 17 acres site flown on overcast days at 300’ altitude above takeoff point with low wind (<4 mph), at a low speed (9 mph) with 18 min duration and 9 passes of 1200’ in an E-W direction show less than 3" altitude error over a 150’ N-S distance. So your results showing a 5 m or 16’ or 0.016" Hg variation in altitude should easily be detected by a P4P. I wager my DJI P4P has a similar barometer. It shows barometric pressure changes as small as 0.001" Hg which is equivalent to about 1’ elevation change. I record barometric pressure during my missions with the Barometer Plus app on my Note 8 phone. Both the car park and the flat roof of the building are perfectly flat / horizontal.ĭid you record the barometric pressure during the flight of the RTK-equiped drone? Most DJI drones use a barometer to control altitude so your results would imply that there is an error in this process. You will see from the aerial image that a large car park deck (painted green, grey and red) has been photographed along with a building running left to right to the south of the car park. Ground Control Points were not inserted as the data didn’t have to be relative to the outside world, just be in proportion with itself. Same goes for the standard elevation colours. The results of this mission however are not giving me confidence they’ve been calculated correctly. Whereas it did seem to take an eternity to process (over 24 hours), I’m also having a large problem with it.īeing on Business obviously provides the ability to view and export at a much higher resolution as well as upload a greater number of images, but the biggest draw of the Business account is the ability to export contours from the Elevation Toolbox. It was uploaded to the cloud on Friday evening and completed processing late on Saturday night. Under my account you will see a mission entitled “Crown Lane”. ![]()
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