The math is simple. It's the required setup that is the trouble, and very much depends on the environment.

For radio, the transfer speed of the signal is too high to measure the arrival time without expensive solutions. So the only practical means is to measure amplitude. Either "fox hunting" by finding the angle of max amplitude, or having enough listening antennas (preferably high enough that the transmission can go straigt to most of them even with people or vehicles moving around) and instead consider the attenuaton based on distance. With weak 433MHz transmitters, the signal strength will very quickly diminish.

The receivers can be very cheap for a 433MHz solution, but do require a "home base", to make it worth drawing out a long enough cable for power + data for a fixed setup. A 10-receiver 433MHz setup should be possible to implemented for < 500$ + backbone cable. And you could probably reach 1-2m precision for a 100x100 ground area. Biggest "if" for precision is amount of uncontrollable clutter.

Obviously, an audio"clicker" solution with sound triangulation is a way (!) nicer alternative, instead allowing the arrival time to be used which also reduces the need for the redundance of receivers a radio amplitude solution with fixed (non-rotating) antennas needs. And the fewer listening posts means ZigBee or similar could be used for reporting back the results, reducing the installation costs to establishing the positions of the listening locations.