I have an Air 2s, and from what I know so far, the TOF sensors on the bottom of the drone are part of the vision system (as DJI refers to them in the manual) and scan the ground for eventual obstacles. And the infrareds are technically for height measurement.

But I don't really know anything else about the infrareds and I'm curious to know what is their exact purpose, why are the infrared sensors paired with the TOF on the bottom of the drone? What function does each couple of sensors have? So this thread is just about me being curious.

Hi there. Thank you for bringing this inquiry to us. The Infrared sensor can detect altitude, so it will use with the downward vision system. Also, these sensors use infrared technology to detect obstacles and avoid collisions, making the drone safer and easier to fly. Hope this helps. Thank you for your valued support.

@Shawgood, surely if you have a TOF sensor the you need an emitter and a receiver so that you can get timings. Since the drone does not emit visible light for height sensing, it would probably be a distraction, then the IR must be used for height sensing? I have not phrased that well but I think you should understand it.