Loran
Loran (long-range navigation) land-based system of radio navigation first developed at Massachusetts Institute of Technology during World War 2 for military ships and aircraft located within 600 miles (about 970 km) of the American coast. In the 1950s a more accurate (within 0.3 mile [0.5 km]), longer-range system (over 2,000 miles [3,200 km]), known as Loran-C, operating in the 90–110 kilohertz range, was developed for civilian use, and the original loran (renamed Loran-A) was phased out. Eventually, Loran-C was extended to cover most of the continental United States and, in cooperation with Canada and Russia, Canadian waters and the Bering Sea.
Loran (long-range navigation) land-based system of radio navigation first developed at Massachusetts Institute of Technology during World War 2 for military ships and aircraft located within 600 miles (about 970 km) of the American coast. In the 1950s a more accurate (within 0.3 mile [0.5 km]), longer-range system (over 2,000 miles [3,200 km]), known as Loran-C, operating in the 90–110 kilohertz range, was developed for civilian use, and the original loran (renamed Loran-A) was phased out. Eventually, Loran-C was extended to cover most of the continental United States and, in cooperation with Canada and Russia, Canadian waters and the Bering Sea.
Sources
https://www.britannica.com/technology/loran