ALEXANDRIA, Va., June 16 -- United States Patent no. 12,306,291, issued on May 20.

"System and method for providing location-based positioning and navigation in GPS-denied environments" was invented by Gregory M. Steinberg (Austin, Texas) and Samuel H. Steinberg (Port Orange, Fla.).

According to the abstract* released by the U.S. Patent & Trademark Office: "System and method for providing location-based positioning and navigation in GPS-denied environments. The method includes Time Domain Reflectometry (TDR) analyzing of varying impedance levels for generating reflection points for indoor location tracking. Next, the method includes receiving the reflection data and operating in at least one of: Very Low Frequency (VLF) and Ultra-Wideband...