LORAN (LOng RAnge Navigation)
- is a terrestrial radio navigation system using low frequency radio transmitters in multiple deployment (multilateration) to determine the location and speed of the receiver.
- The most recent version of LORAN in use is LORAN-C, which operates in the low frequency portion of the electromagnetic spectrum from 90 to 110 Kilohertz.
-LORAN was an American development, advancing the technology of the British GEE radio navigation system that was used early in World War II. While GEE had a range of about 400 miles (644 km), initial LORAN systems had a range of 1,200 miles (1,930 km).
-It originally was known as "LRN" for Loomis Radio Navigation, after Alfred Lee Loomis, who invented the longer range system and played a crucial role in military research and development during World War II, but later was renamed to the abbreviation for the more descriptive term.
- LORAN systems were built during World War II after development at the Massachusetts
Institute of Technology (MIT) Radiation Laboratory and were used extensively by the US
Navy and Royal Navy.
“ Diagram of the LORAN principle ”
The difference between the time of reception of synchronized signals from radio stations A and
B is constant along each hyperbolic curve; when demarcated on a map, such curves are known as "TD lines" •
The navigational method provided by LORAN is based on the principle of the time difference between the receipt of signals from a pair of radio transmitters.
A given constant time difference between the signals from the two stations can be represented by a Hyperbolic Line of Position (LOP).
If the positions of the two synchronized stations are known, then the position of the receiver can be determined as being somewhere on a particular hyperbolic curve where the time difference between the received signals is constant.
In ideal conditions, this is proportionally