Almost everybody interested in radio has run across the question of how to determine the location of a transmitter that reports neither identification nor location. Maybe somebody is trying to locate a numbers station, a jammer, a pirate station, or some unknown source of noise. In all of these cases, somebody is trying to determine the physical location of a transmitter.

My interest is closely related but slightly different - I'm interested in verifying the reported location of other hams. Why bother verifying? Well, many aspects of the hobby depend on location information, awards and contests being two obvious examples. We see a similar desire to verify in systems like the ARRL's "Logbook of the World" and WSJT-X's "SuperFox Mode". Both use cryptographic methods to establish some degree of identity verification from which locations can be "reasonably" inferred. But, unlike those systems, I would like to more-directly verify reported locations by analyzing signals.