How to determine the distance between two objects using radio communication?

Question

Bluetooth

Task: roughly determine the distance between two people (with an accuracy of tens of centimeters). Working distance - from several meters to direct contact.
Why is it necessary: ​​in the luminous costumes of street theater characters that I design, it is necessary to build in a certain reaction to the approach of their "Leader". The closer it is, the stronger the reaction (glow of LED strips in a certain mode) should be, and vice versa.
Solutions: as I understand it, you can use a 433 MHz radio, Bluetooth or WiFi modules, all this works fine with the Arduino used in the project. However, I cannot figure out how to determine the signal level (and draw conclusions about the distance between objects from it).
Tell me please.

Answer 1

I don’t know if this issue is still relevant, but I somehow read about the AT86RF233 mikruha. There's a built-in distance measurement solution.