“So a Drone with its own GPS along with BLE, or just the
passive ability to detect BLE (or whatever type of signals
you care to design for) can fly around and take multiple
measurements, and share with other units doing the same and
thus triangulate in 3 space all the target emissions.”
I think you need. to research BLE positioning technology.
You don’t actually have to use the BLE positioning tech,
if you can detect it’s EM radiation and triangulate the source.