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Validating the Model
Methodology
Tested 4 drones
- DJI Mini 2
- Autel Evo II Pro v3
- DJI Inspire 2
- AgEagle eBee
Horizontal Flight
Measurement Issues
GPS can be inaccurate, timing can be inaccurate, measurements can be inaccurate.
While we strived to ensure accurate measurements, it must be noted that there may be inaccuracies.
What are the GPS accuracies? How does timing affect results?
GPS errors are independent of distance, the further away the drone is, the less it matters. Calculations are more sensitive to horizontal errors than vertical errors.
At roughly 600 ft, it’s about 0.03 arc minutes per foot. Timestamps could be off by seconds, travelling at 25 ft/sec - being off by 3 seconds could mean an inaccuracy of an arc minute or greater if travelling to/from the observer. Devices are synchronized manually prior to each flight and compared against https://www.time.gov/ for validation.
Experimental Results
Visibility by Estimated Acuity
The experimental results show a clear pattern of reduced self-reported visibility when the visual acuity is approaching 3 arc minutes, with 0% self-reported visibility when less than 1 arc minute, roughly assumed to be the limit of human vision.