Milestone-Proposal:LORAN: Difference between revisions
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{{ProposalEdit|a1=LORAN|a2a=Cambridge MA|a2b=Boston Section|a3=1940 to 1946|a4=LORAN is a hyperbolic system of navigation by which difference in distance from two points on shore is determined by measurement of the time interval between reception of pulse- modulated synchronized signals from transmitters at the two points. The name LORAN is derived from long-range navigation. Since it operates in the 1,750 to 1,950 kc frequency range, both ground waves and sky waves can be used to to provide coverage over an extensive area with few stations. An important advantage of loran during the WW2 was that a ship could use loran without breaking radio silence. Loran transmitting stations work in pairs. Synchronization is achieved by letting the signals of the Master station, control those of the Slave station. To help overcome the disadvantage of requiring two transmitting stations for a single family of hyperbolic lines of positions, loran forms a chain of stations, so that each station except the end ones operate with the station on either side to form an intersecting lattice of position lines. | {{ProposalEdit|a1=LORAN|a2a=Cambridge MA|a2b=Boston Section|a3=1940 to 1946|a4=LORAN is a hyperbolic system of navigation by which difference in distance from two points on shore is determined by measurement of the time interval between reception of pulse- modulated synchronized signals from transmitters at the two points. The name LORAN is derived from long-range navigation. Since it operates in the 1,750 to 1,950 kc frequency range, both ground waves and sky waves can be used to to provide coverage over an extensive area with few stations. An important advantage of loran during the WW2 was that a ship could use loran without breaking radio silence. Loran transmitting stations work in pairs. Synchronization is achieved by letting the signals of the Master station, control those of the Slave station. To help overcome the disadvantage of requiring two transmitting stations for a single family of hyperbolic lines of positions, loran forms a chain of stations, so that each station except the end ones operate with the station on either side to form an intersecting lattice of position lines. | ||
Loran consist of three components: 1. a chain of radio transmitters in operations 24/7 to create an electronic lattice or grid upon the surface of the earth. 2. a loran receiver-indicator in each ship or aircraft and 3. loran nautical charts or tables published by the US Navy Hydrographic Office. A simple explanation of loran can be found is section on loran as an Attachment named "American Practical Navigator" | Loran consist of three components: 1. a chain of radio transmitters in operations 24/7 to create an electronic lattice or grid upon the surface of the earth. 2. a loran receiver-indicator in each ship or aircraft and 3. loran nautical and aeronautical charts or tables published by the US Navy Hydrographic Office. A simple explanation of how loran works can be found is section on loran as an Attachment named "American Practical Navigator" | ||
INSERT OR REFER TO DOC.. | INSERT OR REFER TO DOC.. | ||
Each ship or bomber required a radio receiver- indicator, something like a electronic stopwatch but with a cathode ray tube, timing circuits, etc. The third system component was Loran charts or tables wasThen the navigator | |||
shipboard navigators | |||
BRIEF DESCRIPTION | |||
HISTORY - USE POINT TO USCG | |||
The following paragraphs tell the story of Loran's beginning, its first leaders, location where the work was performed, the installation of the first | The following paragraphs tell the story of Loran's beginning, its first leaders, location where the work was performed, the installation of the first | ||
Engineering is not a solo activity. When a grande long-lived engineered system like LORAN, .. this nomination milestone gives credit to those persons that worked on the so-called Project 3 or C of the Radiation Laboratory of MIT during 1941 to c1946. This group of individuals did not work in the Rad Lab building, having nothing to do with microwave or radar. These individuals work in the Hood Building and other building in Boston and Cambridge. The USCG had a permanent office working on this project. One person in particular that deserves mention is Coast Guard Lt. Cmdr. L.M. Harding who provided supervision and direction for the Pacific Loran ... | Engineering is not a solo activity. When a grande long-lived engineered system like LORAN, .. this nomination milestone gives credit to those persons that worked on the so-called Project 3 or C of the Radiation Laboratory of MIT during 1941 to c1946. This group of individuals did not work in the Rad Lab building, having nothing to do with microwave or radar. These individuals work in the Hood Building and other building in Boston and Cambridge. The USCG had a permanent office working on this project. One person in particular that deserves mention is Coast Guard Lt. Cmdr. L.M. Harding who provided supervision and direction for the Pacific Loran ... | ||
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JA Pierce | JA Pierce | ||
“In less than 5 years, loran, the American embodiment of a new method of navigation, has grown from a concept into service used by tens of thousands of navigators over three tenths of the surface of the earth. Even under the stress of military urgency, the direct cost of this system has been less than two percent of the seventy-five million dollars so far spent for operational equipment. ” JA Pierce 1946. | “In less than 5 years, loran, the American embodiment of a new method of navigation, has grown from a concept into service used by tens of thousands of navigators over three tenths of the surface of the earth. Even under the stress of military urgency, the direct cost of this system has been less than two percent of the seventy-five million dollars so far spent for operational equipment. ” JA Pierce 1946. | ||
“With the realization that an effective new aid to navigation had come into being, a Naval Training School for station operators | “With the realization that an effective new aid to navigation had come into being, a Naval Training School for station operators, shipboard navigators was set up (Boston or Cambridge) and turned over by the Radiation Laboratory to the Coast Guard and the Canadian Navy. The three northern stations came into operation in the spring of 1943, and were also turned over to the Coast Guard after operation had become routine. The Bureau of Ships began to take over the procurement of ground-station equipment, while the Army Air Forces were contracting for the development of an | ||
air-borne receiver-indicator.” JA Pierce. | air-borne receiver-indicator.” JA Pierce. | ||
“In the summer of 1943, the United Coast Guard made the first independent installation of LORAN transmitting stations in the Aleutian Island. The equipment in this case had been constructed in the Radiation Laboratory, as Naval procurement had not yet come into effect. Since then, the Coast Guard has installed some twenty-five stations in the Pacific, climaxing its efforts with stations at Jima and Okinawa, which were erected closely on the heels of the invading forces. Of special significance in the Pacific warfare were stations in the Mariannas, which provided very effective guidance for the 20th Air Force in its bombing of Japan.” | “In the summer of 1943, the United Coast Guard made the first independent installation of LORAN transmitting stations in the Aleutian Island. The equipment in this case had been constructed in the Radiation Laboratory, as Naval procurement had not yet come into effect. Since then, the Coast Guard has installed some twenty-five stations in the Pacific, climaxing its efforts with stations at Jima and Okinawa, which were erected closely on the heels of the invading forces. Of special significance in the Pacific warfare were stations in the Mariannas, which provided very effective guidance for the 20th Air Force in its bombing of Japan.” | ||
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Most of the activities from the beginning to the end of the way in 1945, either took place or were managed out of Cambridge. | Most of the activities from the beginning to the end of the way in 1945, either took place or were managed out of Cambridge. | ||
) was to be a pulsed hyperbolic radio navigation system operating in the low end of the VHF spectrum, at about 30 MHz - very like Gee, which the Americans knew nothing about at the time. It eventually became the Loran-A system, out of which Loran-C was born. Loran-A operated in the 1850 to 1950 kHz band, used pulse-time difference as its operating principle and generally speaking had a day/night range of about 800 to 1600 nm depending on whose reference you read. | ) was to be a pulsed hyperbolic radio navigation system operating in the low end of the VHF spectrum, at about 30 MHz - very like Gee, which the Americans knew nothing about at the time. It eventually became the Loran-A system, out of which Loran-C was born. Loran-A operated in the 1850 to 1950 kHz band, used pulse-time difference as its operating principle and generally speaking had a day/night range of about 800 to 1600 nm depending on whose reference you read. | ||
LORAN Principle | LORAN Principle use | ||
BOSDWITCH pdf | |||
Principle | Principle | ||
A crude 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" | A crude 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" | ||
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The Coast Guard published a Federal Register notice on Jan. 7, 2010, regarding its intention to terminate transmission of the LORAN-C signal Feb. 8, 2010. A LORAN Programmatic Environmental Impact Statement Record of Decision stating that the environmentally preferred alternative is to decommission the LORAN-C Program and terminate the North American LORAN-C signal was http://www.navcen.uscg.gov/loran/default.htmpublished in the Federal Register on Jan. 7, 2010.
| The Coast Guard published a Federal Register notice on Jan. 7, 2010, regarding its intention to terminate transmission of the LORAN-C signal Feb. 8, 2010. A LORAN Programmatic Environmental Impact Statement Record of Decision stating that the environmentally preferred alternative is to decommission the LORAN-C Program and terminate the North American LORAN-C signal was http://www.navcen.uscg.gov/loran/default.htmpublished in the Federal Register on Jan. 7, 2010.
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USCG announces LORAN-C termination | USCG announces LORAN-C termination | ||
REFERENCES | REFERENCES | ||
JA Pierce, "An Introduction to Loran", IEEE AES Magazine 1990 (attached) | JA Pierce, "An Introduction to Loran", IEEE AES Magazine 1990 (attached) | ||
Bowditch, American Practical Navigator.U.S. Navy Hydrographic Office, 1958 pp. 333 - 343 | Bowditch, American Practical Navigator.U.S. Navy Hydrographic Office, 1958 pp. 333 - 343 | ||
http://www.loran-history.info/ | http://www.loran-history.info/ | ||
http://www.uscg.mil/history/stations/loran_volume_1_index.asp | http://www.uscg.mil/history/stations/loran_volume_1_index.asp | ||
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http://www.uscg.mil/History/STATIONS/LORAN_Section_1.asp | http://www.uscg.mil/History/STATIONS/LORAN_Section_1.asp | ||
http://www.scribd.com/doc/35814242/MIT-Radiation-Lab-Series-V2-Radar-Aids-to-Navigation | http://www.scribd.com/doc/35814242/MIT-Radiation-Lab-Series-V2-Radar-Aids-to-Navigation | ||
TO PROBE FURTHER | |||
I. B.W. Sittelry, “ELEMENTS OFLORAN,” MIT Radiation Laboratoyr Re- port No. 499; March, 1944; also available as Navships 900, 027, Bureau of Ships, April 1944 | I. B.W. Sittelry, “ELEMENTS OFLORAN,” MIT Radiation Laboratoyr Re- port No. 499; March, 1944; also available as Navships 900, 027, Bureau of Ships, April 1944 | ||
2. Bureau of Ships, “LORAN HANDBOOK FOR SHIPBOARD OPERATORS,” Ships 278; July. 1944 | 2. Bureau of Ships, “LORAN HANDBOOK FOR SHIPBOARD OPERATORS,” Ships 278; July. 1944 | ||
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There is no equal to or competing electrical engineered system The loran project was an engineered systdem was designed, builtof | There is no equal to or competing electrical engineered system The loran project was an engineered systdem was designed, builtof | ||
To what extent loran was born out of Gee's concepts is unresolved and academic. Gee was also a pulse-modulated hyperbolic navigation system, similar to loran. Gee operated at lower frequencies and was limited to line-of-sight distances, of 400 miles or so. Gee was intended primarily for aircraft during WW2. | To what extent loran was born out of Gee's concepts is unresolved and academic. Gee was also a pulse-modulated hyperbolic navigation system, similar to loran. Gee operated at lower frequencies and was limited to line-of-sight distances, of 400 miles or so. Gee was intended primarily for aircraft during WW2. | ||
Atlantic | Atlantic | ||
Although there were other hyperbolic air navigation system at the time, notably the British gee system, none designed nor available nor existed to aid the war effort. he gee system was used in the UK. | Although there were other hyperbolic air navigation system at the time, notably the British gee system, none designed nor available nor existed to aid the war effort. he gee system was used in the UK. | ||
Revision as of 21:33, 9 December 2010
This Proposal has not been submitted and may only be edited by the original author.
Pierce Loran.pdf
