You dont have to do it manually. Nowadays you can grab whole 2.4-2.5 range(most common drone remote frequency), process it in real time, at 3 locations simultaneously, and produce signal position map with every transmitter inside the triangle or interest. Even amateur fox hunts can be automated to the point of trivializing whole thing with couple of those https://www.indiegogo.com/projects/kerberossdr-4x-coherent-r... . More professional hardware does exist, quick search gave me http://spectrafold.com/quadrus/product/dru-244a-1-4-pci/ so Im sure MIL already uses this instead of primitive manual techniques.
You dont have to do it manually. Nowadays you can grab whole 2.4-2.5 range(most common drone remote frequency), process it in real time, at 3 locations simultaneously, and produce signal position map with every transmitter inside the triangle or interest. Even amateur fox hunts can be automated to the point of trivializing whole thing with couple of those https://www.indiegogo.com/projects/kerberossdr-4x-coherent-r... . More professional hardware does exist, quick search gave me http://spectrafold.com/quadrus/product/dru-244a-1-4-pci/ so Im sure MIL already uses this instead of primitive manual techniques.