Electronic signal tracking has been used for decades in maritime environments to guide ocean-going ships. An early navigation system, LORAN, short for long range navigation, was a hyperbolic radio navigation system that employed triangulation from a set of land-based beacons to assist navigation. Accuracy was marginal, being a few hundred feet at best, but this was sufficient in an open ocean environment, and benefited from a generally flat and unobstructed path. More recently, consumer-oriented GPS (Global Positioning Systems) have become commonplace, using satellite ranging algorithms formerly deployed for military use. While suitable for general vehicle navigation, such systems enjoy a largely unobstructed path from the satellite beacons (transmitters) and are still susceptible to weather (overcast) conditions. Ranging and tracking in walled, indoor environments, such as for first responders and military applications, rarely benefits from line-of-sight proximity to a distressed subject. Indoor environments present a myriad of extraneous effects on propagated signals from metal framing and structural members as well as competing EMF (Electromagnetic Field) sources common in a modern structure wired for traditional electrical as well as broadband, optical and other Internet connectivity.