Milestone-Proposal:LORAN: Difference between revisions

Revision as of 14:06, 7 December 2010

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 {{ProposalEdit|a1=LORAN|a2a=Cambridge MA|a2b=Boston Section|a3=1940 to 2010|a4=Long lasting near global radio navigation system.
-How the LORAN project was initiated, organized and managed is very interested, if not note worthy.
+First LORAN signal began transmissions during the summer 1941. New LORAN transmitting stations were added around the Atlantic coast throughout WW2 and the continental United States. The LORAN-C system became obsolete, replaced by GPS navigation system and the LORAN system was terminated in a special ceremony orchestrated by USGC Washington headquarters in 8 February 2010.theHow the LORAN project was initiated, organized and managed is very interested, if not note worthy.
 Rapid construction under extreme weather conditions. System operation by operators from different nations: US, Canada and Denmark. Collaborative effort. MIT Lab was initially responsible for the entire program, but under close hands-on direction of the USCG.  USGC's role increased.
 This was a completely successful American project, completed under trying time, progressing during wartime conditions without major false starts There was an exchange of radio engineering technology with the British GEE radio navigation but this is believed to have been minimal and had more to do with RAF bombers having the capability to accompanied  two different size of receivers in the cockpit.
 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.
 LORAN 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"
 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.[6] A given constant time difference between the signals from the two stations can be represented by a hyperbolic line of position (LOP).
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 A LORAN network with only two stations cannot provide meaningful navigation information as the 2-dimensional position of the receiver cannot be fixed due to the phase ambiguities in the system and lack of an outside phase reference.
 A second application of the same principle must be used, based on the time difference of a different pair of stations. In practice, one of the stations in the second pair also may be—and frequently is—in the first pair. In simple terms, this means signals must be received from at least three transmitters to pinpoint the receiver's location. By determining the intersection of the two hyperbolic curves identified by this method, a geographic fix can be determined.
 LORAN-C END PIECE
 LORAN-C GENERAL INFORMATION
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 LORAN-C Termination Information
 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.
 USCG announces LORAN-C termination
 http://www.insidegnss.com/node/1806#Baseband_Technologies_Inc_
 LORAN- History. info website
 Wikipedia. LORAN
 http://en.wikipedia.org/wiki/LORAN#History
 http:/ www.jproc.ca/hyperbolic/loran_a.html
 HYPERBOLIC RADIO NAVIGATION SYSTEMS
 THE COAST GUARD AT WAR: IV  LORAN  VOLUME I
 Willoughy, Malcom Francis; The Story of LORAN in the U.S. Coast Guard in World War II, Arno Pro, 1980
+SECTION I
+http://www.uscg.mil/History/STATIONS/LORAN_Section_1.asp|a5=Time was critically important, getting the radio navigation grid up and running
-SECTION I
-http://www.uscg.mil/History/STATIONS/LORAN_Section_1.asp
-|a5=Time was critically important, getting the radio navigation grid up and running
 fast track electronic / radio navigation system
 Construction, O&M and dedicated persons / Hers
 How the early system evolved:
 Station #1,2,3 and 4
 The first Loran-A pair was on the air permanently by June 1942 (Montauk Point, NY, and Fenwick Is, Del.), and by October there were additional stations along the Canadian east coast. The system became operational in early 1943, and late that year stations were established in Greenland, Iceland, the Faeroes and the Hebrides to complete the North Atlantic cover, some being operated by the Royal Navy. At the request of the RAF, another station was put into the Shetlands to cover Norway, and Loran was eventually used by over 450 aircraft of Coastal Command.
 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.
 for two years (c 1941-1943) he was on leave of absence from his company to the Radiation Laboratory of Massachusetts Institute of Technology for this work.When these projects finally reached fruition and combat equipment based on them reached the battlefronts, he returned to the General Radio Company and resumed the active direction of the engineering staff.
 General Radio Corp sponsored radio techs
 Divison 11 “Navigation Group” 1941 -  1943 by Melville Eastman. Eastman replaced by Donald G Fink  March 1943.
 Lt. Cdmr. Harding would be an acceptable officer, Captain Harding received orders to report to the Chief of naval Operations on 25 May 1942 and was the immediately ordered to temporary duty in Cambridge, Massachusetts, the first week in June.
 John (Jack) A. Pierce, who retired from a position as a senior research fellow at Harvard University, Cambridge, Mass. was awarded the Medal For Engineering Excellence in 1990 for the "design , teaching and advocacy of radio propagation, navigation and timing which led to the development of Loran,  Loran C and Omega." In 1941, Pierce began working at the Massachusetts Institute of Technology's Radiation Laboratory which was testing the United States' first hyperbolic radio aid to navigation called Loran. It inaugurated in October 1942. Later work produced Loran C which operated at a lower frequency of 100 kHz. After WWII, he was appointed senior research fellow in applied physics at Harvard and from 1950 to 1974 did work on low frequency navigation aids that lead to Omega.
-Coast Guard Lt. Cmdr. L.M. Harding
+Coast Guard Lt. Cmdr. L.M. Harding|a6=Location of transmitters around the world in remote wilderness areas.
+Defficulties of supplying the LORAN crews
+Construction in remote areas
+Need for international cooperation - between Canada, Denmark.
+Lack of qualified radio operators. Training . .
+It was imperative for the war effort to protect / guide  military planes and convoys across the barren northern waters, that LORAN system of radio navigation be in service quickly and reliably. One system design was complete, LORAN radio stations had to be erected. Then radio technicians and operators had to be selected and trained on how to work the new transmitters and receivers.
- |a6=It was imperative for the war effort to protect / guide  military planes and convoys across the barren northern waters, that LORAN system of radio navigation be in service quickly and reliably. One system design was complete, LORAN radio stations had to be erected. Then radio technicians and operators had to be selected and trained on how to work the new transmitters and receivers.
 USCG
 Captain L. M. Harding
 Captain Harding took up temporary duty at the Radiation laboratory, Cambridge, Mass on 3 June 1942.
 Captain Harding and Mr. Eastham pressed plans for practical trials and shakedown to evaluate the developments quickly.
 it was planned that the two already practically established experimental station at Fenwick and Montauk, would be Units #1 and #2 respectively, and that Units #3 and #4 would be located along the Coast of Nova Scotia, at sites tentatively selected and agreed upon between U.S. Navy (Capt. Harding), Royal Canadian Navy (Commander Worth) and Radiation Laboratory (Mr. Eastham).
 Captain Harding therefore arranged for observations and tests to be made from a Navy blimp, during June, and more important, he arranged to have receiving equipment installed on a Coast Guard weather ship, the USS MANASQUAN, so that an adequate navigational test might be made.
 Davidson and Duvall, the latter a recent addition to the Laboratory staff and an ex-Naval officer and navigator, were assigned to conduct tests on the USS MANASQUAN, which continued for one month, from June to July of 1942.
 long range navigation by pulse radiation was a practical possibility, but Mr. Duvall's records would give an indication as to the line that future development for such navigation would follow.
 At about this time, Captain Harding coined the word "Loran" as a convenient designator for the project, deriving the word from "long range radio navigation". This was accepted by both the Navy and Radiation Laboratory.
 middle of June 1942 and ground was broken at Boccaro on 19 June and at Deming on 27 June. One shipment of supplies had been held up awhile through the refusal of a local Canadian freight agent to honor a USN bill of lading for necessary supplies the U.S. Navy had furnished. The contractor employed, had to, in effect, bail out his supplies by guaranteeing the freight charges.
 OPS TRAINING
 so in June 1942 several men were selected to train in operation and maintenance at the Radiation laboratory, and also at the two stations in operation at Fenwick and Montauk.
 the Laboratory requested Captain Harding to obtain personnel either from the U.S. Navy or the U.S. Coast Guard to man the proposed Greenland station, and also eventually to man the units at Fenwick and Montauk.
 Commander MacMillan, USCR, Captain Harding, USCG, and Dan Fink of the Radiation laboratory departed Quonset, R.I. in a U.S. Naval seaplane, 15 July 1942, they stopped briefly at Shediac, New Brunswick to pick up Dr. Waldschmitt and Lt. Comdr. Argyle, RCNR,
 Future events in the construction of these two stations proved Captain Harding warnings only a mild forecast of actual happenings.
 Upon his return to Cambridge, Captain Harding found the results of the tests made on the USS MANASQUAN which had been completed 17 July awaiting him. These tests which were primarily to determine the service range of the Loran system, showed most satisfactory results. The ground waves were efficient up to 680 miles in the daytime when the reflecting Heaviside layer was affected by the sun, and were effective up to 1,300 miles at night when the Heaviside layer was reflecting the sky waves to earth.
 The Radiation Laboratory, however, was encountering increasing difficulties in supplying adequate operating and maintenance personnel for the two original units at Fenwick and Montauk.
 The Laboratory's predicament is not difficult to comprehend in the light of a few basic facts. While the staff of the Radiation Laboratory was undoubtedly composed of brilliant scientists, very few had any practical experience in the operation and maintenance of a transmitting station. The ranks of available, competent radio operators and maintenance technicians were meanwhile thinning swiftly as increasing numbers of civilians entered the armed forces.
 Each day, more and more of the problem of procuring supplies, materiel and personnel was shifted from the Radiation laboratory onto the Navy and the Coast Guard. There was also the problem of equipment production.
 Had to be designed and deployed in secret during WW2 with the participation of Canada and Britain. The first series of LORAN stations were installed along the north Atlantic coast in Canada in Greenland. Stations
+were located in very remote  location subject to very harsh climates. A large number of radio operators and technicians from the USCG and foreign countries had t be trained.
- were located in very remote  location subject to very harsh climates. A large number of radio operators and technicians from the USCG and foreign countries had t be trained.
 By July of 1943 also two other projects long recommended by Captain Harding began to take definite shape and proportions. The report of Lt. Cowie Acting NLOL for June 31 states;
 "Development of technique and equipment for providing day-time service equal in radius to night-time service by use of a single high frequency...status: investigation of E-layer day-time transmission of high frequency has been completed and the use of a frequency of approximately 10.5 mcs. authorized. It is the opinion of Radiation Laboratory that this frequency will give a satisfactory day-time range of service from 800 to 1,300 miles although it is expected that the 10.5 mcs. signals will be some what weaker that 2 mc. signals. A program to obtain and modify transmitters and start a service test on this frequency will be started in the near future."
 The experiments that had been in progress for some time in the Laboratory to develop an automatic synchronizer seemed also to begin bearing fruit as about this time one was developed which did not deviate nor lose control through high noise levels including electrical storms. Four of these units were being built by the laboratory and by July so confident were they of the worth of the auto-sync that the Laboratory placed an order for sixty of these units based on their prototype to be delivered around the end of 1943.
 REFERENCES
- 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
 Wikipedia, LORAN http://en.wikipedia.org/wiki/LORAN|a7=The original research and design work was carried out in the Hood Building in Cambridge, close to but outside the MIT campus. The proposed milestone plaque could be mounted on MIT Building N42, on Massachusetts Avenue, close to where the original Hood Building used to be. The Boston Section Milestone Committee is currently seeking approval from MIT to carry this out