Introduction

Welcome to the LORAN Resource Center! Our name is Team FPG-eh. We're a group of LORAN-C aficionados hoping to promote the LORAN positioning system through education and activism.

In February 2007, we began to develop a LORAN-C Positioning System for a DSP Design course (EECS 452) at the University of Michigan (Ann Arbor). Our team - comprised of three graduate and two undergraduate students - developed this system in just under eleven weeks. We obtained coaching and support from two graduate student instructors and one professor. We published this website in part to present the results of our team's efforts.

However, the LORAN Resource Center has another important function. Early in our research process, we found that LORAN-related information was difficult to find. We searched several libraries and Internet sources to find even the most menial information on the LORAN system and its receiver-side algorithms. More complex information was almost impossible to find. This is due in part because much of the LORAN-C literature was written almost sixty years ago. In addition, modern LORAN-C systems are sold by electronics companies that aren't enthusiastic about divulging their intellectual secrets.

But, the LORAN system is currently in a period of flux. Engineers within both the government and private sectors are engaged in a fierce debate regarding the future of LORAN. Many people want to drop the LORAN system in favor of satellite-based GPS; others would rather see LORAN as a GPS backup. We believe that LORAN is still relevant in today's world: its characteristics often match or exceed GPS technology; modern DSP technologies can further expand its capabilities; and, it can redundantly perform critical tasks that currently rely on vulnerable satellites.

LORAN will only survive if engineers continue to work with and develop its technologies. And, to further its use, engineers must have simpler access to relevant information. For this reason, the LORAN Resource Center aims to provide a one-stop source for basic LORAN data; whether you're searching for information on LORAN-C, eLORAN, TD-coordinate conversions, skywave propagation, or receiver-side algorithms, chances are you'll find some help in here. This information is generally targetted toward those engineers who are just getting started in LORAN, and is not meant to be a extensive professional resource. Our hope is to generate interest in LORAN by extending our support to those who are embarking on a research and development process that is just as clueless as ours had been in February 2007.

Continue reading our Home page to learn more about LORAN. We detail what LORAN is, how LORAN works, where LORAN's been, and where LORAN's going. We also provide links to relevant websites and basic LORAN references. Our Demonstration page explains our receiver design and presents the results of our work. You can also read about us - i.e., we of Team FPG-eh - on our Bio page; and, you can read about all the current efforts to promote LORAN on our Save LORAN! page. Be sure be sure to sign our petition to the Coast Gaurd!

Thank you again for visiting our site!

History of LORAN

The LORAN (Long Range Navigation) system was first developed during World War II to aid the United States military in the Pacific theatre. Its development began in May 1942, when the United States Navy and Coast Gaurd requested the support of Capt. L. M. Harding at the MIT Radiation Laboratory in Cambridge, MA. With the help of the National Defense Research Council (NDRC), the Canadian Navy, and John Alvin Pierce - the "Father of LORAN" - Harding coordinated the military's development of the LORAN system. At the time, the project was so secretive that even the highest levels of the military were only aware that it was related to an electronic device that might have wartime navigational importance.

The LORAN system was an extension of the British GEE (or, AMES Type 7000) system, which was used to improve the accuracy of aircraft navigation, thereby increasing the effectiveness of wartime bombing raids. At the time, the GEE system had a range of approximately 400 miles. At short range, it was accurate to about 165 yards; but, at long range, it was accurate to approximately one mile. By the time LORAN saw action in World War II, it had a range of approximately 800 miles, and, at best, was accurate to approximately 6000 feet. By this time, LORAN-A (as the system came to be known) was used widely by both the United States and British navies.

The United States used the LORAN-A system throughout the 1950s. Large American aircraft even used this system during the Vietnam War. But, the 1950s also experienced the continued development of longer-range terrestial navigation systems. At the time, the United States believed LORAN-A limited its military capabilities because the Pacific islands upon which transmitters were built were too few and far away for the system to be effective. Engineers initially experimented with LORAN-B - a variant of LORAN-A - but did not develop the system beyond the research stage. In 1957, the United States Navy established LORAN-C transmitters in the Northeast Atlantic and Mediterranean regions, and soon built additional transmitters in the Pacific. In the early 1960s, the United States Air Force began its experiments with LORAN-C navigation; and, by the late 1960s, it built LORAN-C transmitters in Vietnam to replace the aging LORAN-A system. The improved system had a range of approximately 1200 miles, and was accurate to approximately 1500 feet. Throughout the 1960s, engineers sought to design other LORAN-type systems - specifically, LORAN-D for short-range aircraft navigation; and, LORAN-F for drone control - but none of them were developed past the research phase.

In 1960, the United State Navy successfully tested Transit: the first satellite-based navigation system. This system allowed the military to fix any position on Earth once every hour, and was accurate to approximately 650 feet. In 1967, the Navy also launched Timation, which transmitted accurate clock signals in space. By the 1970s, engineers began to search for a satellite-based replacement to LORAN. Such a system would allow the military to navigate continuously from any location on Earth. In 1978, the United States launched the first Block-I NAVSTAR GPS (Navigation Satellite Timing and Ranging Global Positioning System) satellite; and, by 1983, President Ronald Reagan pledged to provide the public with GPS technology when the system was built. In 1993, the GPS system became operational; and, soon, discussions arose to discontinue the LORAN-C program.

Despite this debate, engineers have continued to advance the LORAN system. Recently, the Federal Aviation Administration and United States Coast Guard have begun to develop the LDC (LORAN Data Channel), which transmits station identification, absolute time, position correction, and other information within the LORAN-C signal. The LDC system is similar to EUROFIX, which transmits differential GPS (DGPS) and other information within European LORAN-C signals. Currently, eight LORAN stations transmit the LDC within the continental United States. The Coast Gaurd has also begun to develop Enhanced LORAN (eLoran), which improves the transmission characteristics and receiver designs of traditional LORAN signals. This system contains additional pulses for DGPS information; and, it is reportedly accurate to approximately 25 feet, which is comparable to unenhanced GPS. The 2005 United States Federal Radionavigation Plan pledged to complete its evaluation of LORAN by the end of 2006; but, by early 2007, its evaluation was incomplete. Regardless, the United States and Europe have promised to maintain and upgrade their LORAN systems, albeit for political reasons.

LORAN is currently found in several regions of the world. The continental United States is completely covered by the LORAN system, as are the coastal and maritime regions of east Asia and central Europe. Smaller LORAN regions are also found in eastern Europe, Russia, Saudi Arabia, and India.

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