Distance between devices in mesh network

[19kzk51]

Hi


I'm doing a Mesh network project on ESP32 to measure the average speed over a given distance. I have microcontrollers mounted on two objects (which are hotwheels), at the moment of crossing the gate the vehicle should be identified and here is the problem. I can't use GPS I know that it is possible to use RSSI to identify which vehicle was closer to the gate when it crossed the gate. Unfortunately I can't find anything anywhere that can somehow direct me on how to use this RSSI. I have found that it is worth writing here and maybe some good soul can be found