Distance tracking of two micros

Projects General Guidance
1

I want to build two units that can track their distance from each other.
I'm thinking something along the line of using two rf transceivers and watching signal strength.
It does not have to be extremely accurate. (I'm going to blink some LEDs as a visual indicator using frequency as the units get closer)

Does anybody have any good, inexpensive solutions for doing this?
Is RF transceivers the best solution?

Thank you in advance!
-Mike

2

You haven't specified any kind of range criteria - centimetres, metres, kilometres?

This subject comes up quite often, and it is a real problem.

Common receivers are designed ensure that the signal gets through, so have gain control built-in, so are not really suitable.