BPS is a GPS alternative working over ATSC 3.0 digital TV signals - CNX Software

Wow, very cool.

Certainly there exists a system(s) that takes input from every kind of existing signal (cell, loran, vhf, ham, gmrs, etc), and can locate based on those?

Location capability from cell alone is pretty accurate, even on phones today (since we have pretty good info on tower location and signal strength).