Urban concrete jungles turn drones into blinded bats. Cameras go blind around every corner, GPS gets lost among skyscrapers, and radio waves scatter into a hundred echoes. The M3F-UAV model overcomes this by merging all available 'ears' and 'eyes': regular cameras, 3D maps from a laser rangefinder, and radio signals — their electromagnetic nature was first described by Maxwell. The AI is trained on entropy, meaning the inevitable disorder in incoming data. Just as a bat learns to isolate prey from acoustic chaos, the algorithm was forced to reconstruct the scene from deliberately damaged sensor streams. If any part fails — say, the camera is blinded by sunlight — the system doesn't stop. It fills in reality from memory and hints, much like spectroscopy extracts a star's secrets from its rainbow spectrum.

The most striking experiment: a drone with cameras and navigation disabled flew half a kilometer through a model city, navigating solely by radio echoes from buildings — pure echolocation, like cave-dwelling bats. Tomorrow, swarms of such drones could search for people under rubble, operate in thick fog and dust storms, delivering cargo without fear of losing sight.