How does a pilot maintain the correct distance from a tanker while refueling in flight?

The former Russian fighter pilot and blogger Fighter Bomber explains it to us:

"Well, of course, in addition to magic, the navigator and the tanker operator help him in this with the UPAZ (Unifitsirovannyy Podvesnoy Agregat Zapravk, in Italian literally Unified Suspended Refueling Unit). This is a probe that can be attacked to different types of aircraft automatically transforming them into oil tankers.Of course, not for everyone.
It is a container with a tube approximately 26 meters long, a sensor cone, an electric motor and an alarm system.
Refueling is carried out at a distance of 22 meters from the UPAZ, and the pilot maintains this distance using the warning system of the UPAZ itself. This is the so-called "traffic light". Let's examine the flashes:

🚦 Green light flashing and red light constantly on: the tanker is ready for refueling.
🚦 Red light on: you are too far from the tanker, you need to get closer.
🚦 Green and red lights on together: the supply is on the border between the red and green zones.
🚦 Green lamp: everything is fine, stay here young man.
🚦 Yellow and green light: refueling in the yellow and green area.
🚦 Yellow lamp: Too close to the tanker, move away!
🚦 Flashing yellow light: you are approaching the tanker at a speed greater than half a meter per second, slow down!
🚦 Flashing red light: you are behind the tanker! Increase your speed!
🚦 All lights flash - no contact allowed. Wait.

With the help of such simple signals, refueling is easy and simple (of course not) 😏