Radio enthusiasts have 'foxhunting' competitions to track down a hidden transmitter.
The receivers can be homebrew designs. They need not be the same brand or manufacturer as the transmitter.
Link to "FOXHOUND" RADIO DIRECTION FINDER KIT. Explaining how it works, and how to construct:
Normally you aim a directional antenna from side to side, while reading the signal strength.
However if you really intend that all devices are stationary, then you might consider VOR beacon signals as airports use. These indicate both direction and distance. Your transmitter will need to be more sophisticated if you go this route.