Future Of Federally Operated Radionavigation Systems

Radionavigation first appeared in the United States as radio direction finding experiments carried out by the U.S. Bureau of Standards in 1912 and 1913.l These experiments resulted in a practical demonstration of radio direction finding using signals from a spark gap transmitter located at the Navesink Lighthouse in New Jersey. This demonstration was conducted jointly by the U.S. Lighthouse Service and the Bureau of Standards in January 1917. Development of radionavigation was suspended during World War I and further testing was not conducted until 1919. The first operational radionavigation system was available for public use on May 1, 1921. It was a Radio Fog signal (also known as a Wireless Fog signal) transmitted from spark gap transmitters installed at the Sea Girt Lighthouse in New Jersey and on the Ambrose and Fire Island Light ships at the entrance to New York Harbor.

Radionavigation first appeared in the United States as radio direction finding experiments carried out by the U.S. Bureau of Standards in 1912 and1913.l These experiments resulted in a practical demonstration of radio direction finding using signals from a spark gap transmitter located at the Navesink Lighthouse in New Jersey. This demonstration was conducted jointly by the U.S. Lighthouse Service and the Bureau of Standards in January 1917. Development of radionavigation was suspended during World War I and further testing was not conducted until 1919.
The first operational radionavigation system was available for public use on May 1, 1921. It was a Radio Fog signal (also known as a Wireless Fog signal) transmitted from spark gap transmitters installed at the Sea Girt Lighthouse in New Jersey and on the Ambrose and Fire Island Light ships at the entrance to New York Harbor.
This radio direction finding system, now known as the Marine Radio Beacon System, has become the cornerstone of maritime navigation. There are now 201 Marine Radio Beacon Transmitting Sites in the United States and there are more users of the Marine Radio Beadon System than of any other radionavigation system. ' The durability of the Marine Radio Beacon System is a characteristic not inherent in the multitude of other radionavigation systems that are now or have been used. An excellent example of how technology has made a radionavigation system obsolete is the short history of the L O W -A system.
The concept for LORAN-A was first proposed by the U.S. Army Signal Corps in 1940 as a precision navigational equipment €or guiding airplanes. LORAN-A was developed at the Massachusetts Institute of Technology Radiation Laboratory with the first tests of the system carried out on the East Coast of the United States in mid 1941. These tests were quite successful and the first operational L O W -A chain was in place in June 1942. The original stations were located at Montauk Point, NY and Fenwick Island, DL. In October 1942 two Canadian stations were added and LORAN-A became an operational reality. By 1945 more than 30,000 aircraft and 3,000 surface ships were equipped with LORAN-A.?
LORAN-A was, however, doomed by the advances of technology. Extensive tests of a much improved system, LORAN-C, were carried out between 1952 and 1955. The first LORAN-C chain consisted of stations at Cape Fear, NC; Carabelle, FL; and Forestport,

NY.
The LORAN-C tests indicated great promise for the system. In 1956 and 1957, the original LORAN-C chain was reoriented to provide its best coverage to sea. The advantages of LORAN-C were immediately obvious; thus began the downfall of LORAN-A.
Today, there are 44 LORAN-C stations providing coverage for the United States, Canada, North Atlantic Ocean, Norwegian Sea, Mediterranean Sea and portions of the Pacific Ocean.3 The LORAN-C system became the designated radionavigation system for the Coastal Confluence Zone of the United States in 1974.
The phase out of LORAN-A began shortly after LORAN-C became the primary Maritime radionavigation system. The last U.S. operated LORAN-A chain was shut down on December 31, 1980. The last Canadian LORAN-A chain, also the last LORAN-A chain in North America, will be shut down on December 31, 1983.
The shut down of one radionavigation system in favor of a more advanced one should not be considered an unusual phenomenon.
The United States operates four major radionavigation systems that benefit the civil maritime community. They are LORAN-C, OMEGA, Marine Radio Beacons and the Navy Navigation Satellite System (TRANSIT).
The NAVSTAR Global Positioning System (GPS) is being readied by the Department of Defense for full operation in 1988. GPS offers an alternative radionavigation system that could replace some or all of the systems now in use.
The redundancy of capability available due to the proliferation of radionavigation systems and the cost savings realized by reducing this redundancy have long been recognized. The termination of L O W -A is an example of a cost savings without reducing the overall radionavigation availability. The need to control the proliferation of federally operated radionavigation systems was highlighted in a Comptroller General's report4 that, late in 1978, prompted Congress to legislate a degree of control over the proliferation of federally operated radionavigation systems. Section 507 of the International Maritime Satellite Telecommunication Act (Public Law 95-564 November 1978) directed that: The President, in conjunction with government agencies which will or may be affected by the development of a government-wide radio navigation plan, shall conduct a study of all government radio navigation systems to determine the most effective manner of reducing the proliferation and overlap of such systems. The objective of such study shall be the development of such a plan." The President shall transmit a report to the Congress no later than 12 months after the date of the enactment of this title relating to the study conducted under subsection (a) of this section. Such report shall contain a detailed statement of the findings and conclusions of such study, any action taken by the President related to such findings and conclus i o n s , and any recommendations of the President for such legislation or other action as the President considers necessary or appropriate for implementation of a government-wide radio navigation plan." This legislation resulted in the formation of a joint Department of Transportation (DOT) and Department of Defense (DOD) Navigation Council to formulate the Plan. The Plan enacted as a result of the Navigation Council's work is known as the "Federal Radionavigation Plan." This plan outlined all federal efforts in the area of radionavigation and specified a procedure to set policy to reduce the proliferation of radionavigation systems. The procedure calls for the Secretaries of Defense and Transportation to make a joint Policy statement establishing a preliminary selection of the post 1995 mix of radionavigation systems in 1983. The procedure requires the policy to be finalized in 1986.5 Figure 1 illustrates the steps in this planning process.
The preliminary selection of the post 1995 mix of federally operated radionavigation systems takes into The 20 meter figure could be met i n some harbors by LORAN-C, b u t i n most c a s e s would not be met by e x i s ting systems except in a d i f f e r e n t i a l mode.

It is d o u b t f u l t h a t t h e 8 meter (2 drms) requirements could be achieved even in
a d i f f e r e n t i a l mode. These extreme accuracy requirements must be s a t i s f i e d by some type of s p e c i a l i z e d s y s t e m , r a t h e r t h a n a g e n e r a l purpose radionavigation system. The major i n s t i t u t i o n a l i s s u e s a r e :