Indoor Location Beacon Working Principle

Right now, my team is doing a project to compare the BLE Beacons and the UWB Beacons for Indoor Location application.
So far, (correct me if I am wrong) our understanding is that with BLE Beacons, the phone will measure the received signal strength from the BLE beacons and through the RSS readings determine the location of the user.
So then how exactly would the UWB beacons work? Would the location of the user be determined through the received UWB signal strength like the BLE?
To be short and precise, what I am looking for is an explanation of how the BLE and UWB beacon can determine the location of the user.
Many thanks in advance.