الملاحة بعيدة المدى

(تم التحويل من لوران)

الملاحة البعيدة المدى وتُسمّى أيضًا لوران LORAN (LOng Range Aid to Navigation) هو نظام ملاحة راديوية أرضي يستخدم إرساليات راديوية ذات تردد منخفض تستعمل عدة إرساليات (multilateration) لتحديد موقع و/أو سرعة المستقبل. وهي نظام ملاحي راديوي يساعد السفن والطائرات على تحديد مواقعها. وترسل محطتان أو أكثر تعرفان باسم المحطة الرئيسية والمحطة التابعة الإشارات الراديوية باستمرار، وتستقبل السفينة أوالطائرة هذه الإشارات من خلال أجهزة خاصة. وتقوم هذه الأجهزة بقياس الفترة الزمنية بين النبضات التي تلتقطها من المحطات. ويحدد الفرق في الزمن بين الإشارات التي تلتقطها من محطتين، موقع السفينة أو الطائرة فوق نقطة ما على خط الموقع اللوراني فوق الخريطة. وتوضع علامة على الخريطة لتحديد موقع السفينة أو الطائرة طبقاً للفرق في الزمن بين الإشارات المرسلة من المحطتين.

وفي معظم الحالات، نجد محطة راديوية رئيسية واحدة يقابلها محطة راديوية تابعة من إحدى محطتي التوابع، حيث يسمح هذا الترتيب للملاح أن يقطع خطي موقع لوراني، ليحدد موقع سفينة أو طائرة وبذلك يحسِّن بدرجة كبيرة من دقة نظام الملاحة.

ويستخدم الملاحون نظامًا راديويًا يُعرف باسم لوران ـ سي يستطيع أن يرسل إشارات تقطع 1,600 كم أثناء النهار. وفي بعض الظروف، يصل مداها إلى أكثر من 4,800 كم أثناء الليل عندما تنتقل موجات الراديو منخفضة التردد إلى مسافات أبعد، وبذلك يمكن تحديد أي موقع داخل مدى حوالي نصف كيلومتر.

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Principle

A crude diagram of the LORAN principle. The difference between the time of receiption of synchronized signals from radio stations A and B is constant along each hyperbolic curve.[بحاجة لمصدر] When demarcated on a map, such curves are known as "TD lines".


LORAN method

LORAN pulse


LORAN chains (GRIs)

LORAN Station Malone, Malone, Florida Great Lakes chain (GRI 8970) / Southeast U.S. chain (GRI 7980)

LORAN charts

This nautical chart of نيويورك Harbor includes LORAN-A TD lines. Note that the printed lines do not extend into inland waterway areas.


Timing and Synchronization

Caesium atomic clocks

Transmitters and antennas

LORAN transmitter bank


انظر أيضاً: الملاحة؛ الشوران.



قائمة إرساليات LORAN-C

A list of LORAN-C transmitters. Stations with an antenna tower taller than 300 metres (984 feet) are shown in bold.

المحطة البلد السلسلة تعليق
Afif Saudi Arabia Saudi Arabia South (GRI 7030)/Saudi Arabia North (GRI 8830)
Al Khamasin Saudi Arabia Saudi Arabia South (GRI 7030)/Saudi Arabia North (GRI 8830)
Al Muwassam Saudi Arabia Saudi Arabia South (GRI 7030)/Saudi Arabia North (GRI 8830)
Angissq Greenland shutdown on December 31, 1994 used until July 27, 1964 a 411.48 metre tower
Anthorn UK Lessay (GRI 6731) replacement for transmitter Rugby[1]
Ash Shayk Saudi Arabia Saudi Arabia South (GRI 7030)/Saudi Arabia North (GRI 8830)
Attu, Alaska United States North Pacific (GRI 9990)/Russian-American (GRI 5980) 52°49′44.134″N 173°10′49.528″E / 52.82892611°N 173.18042444°E / 52.82892611; 173.18042444 (Attu (LORAN))
Balasore India Calcutta (GRI 5543)
Barrigada Guam shut down
Baudette, Minnesota United States North Central U.S. (GRI 8290)/Great Lakes (GRI 8970) 48°36′49.947″N 94°33′17.915″W / 48.61387417°N 94.55497639°W / 48.61387417; -94.55497639 (Baudette (LORAN))
Berlevåg Norway Bø (GRI 7001)
Billamora India Bombay (GRI 6042)
Boise City, Oklahoma United States Great Lakes (GRI 8970)/South Central U.S. (GRI 9610) 36°30′21″N 102°53′59″W / 36.50583°N 102.89972°W / 36.50583; -102.89972 (Boise City (LORAN))
Bø, Vesterålen Norway Bø (GRI 7001)/Eiði (GRI 9007)
Cambridge Bay Canada shut down free-standing lattice tower, used as NDB
Cape Race Canada Canadian East Coast (GRI 5930)/Newfoundland East Coast (GRI 7270) used a 411.48 metre tall tower until February 2, 1993, uses now a 260.3 metre tall tower 46°46′32.286″N 53°10′27.606″W / 46.77563500°N 53.17433500°W / 46.77563500; -53.17433500 (Cape Race (LORAN))
Caribou, Maine United States Canadian East Coast (GRI 5930) / Northeast U.S. (GRI 9960) 46°48′27″N 67°55′37″W / 46.80750°N 67.92694°W / 46.80750; -67.92694 (Caribou (LORAN))
Carolina Beach, North Carolina United States Northeast US (GRI 9960)/ Southeast U.S. (GRI 7980) 34°3′46″N 77°54′46″W / 34.06278°N 77.91278°W / 34.06278; -77.91278 (Carolina Beach (LORAN))
Chongzuo China China South Sea (GRI 6780) 22°32′35″N 107°13′22″E / 22.54306°N 107.22278°E / 22.54306; 107.22278 (Chongzuo (LORAN))
Comfort Cove Canada Newfoundland East Coast (GRI 7270) 49°19′53.57″N 54°51′42.57″W / 49.3315472°N 54.8618250°W / 49.3315472; -54.8618250 (Comfort Cove (LORAN))
Dana, Indiana United States Great Lakes (GRI 8970)/ Northeast US (GRI 9960) 39°51′07.658″N 87°29′11.586″W / 39.85212722°N 87.48655167°W / 39.85212722; -87.48655167 (Dana (LORAN))
Dhrangadhra India Bombay (GRI 6042) 23°00′14″N 71°31′39″E / 23.00389°N 71.52750°E / 23.00389; 71.52750 (Dhrangadhra (LORAN))
Diamond Harbor India Calcutta (GRI 5543) 22°10′18″N 88°12′25″E / 22.17167°N 88.20694°E / 22.17167; 88.20694 (Diamond Harbor (LORAN))
Eiði Faroe Islands Ejde (GRI 9007)
Estartit Spain Mediterranean Sea (GRI 7990); shut down
Fallon, Nevada United States U.S. West Coast (GRI 9940) 39°33′06.740″N 118°49′55.816″W / 39.55187222°N 118.83217111°W / 39.55187222; -118.83217111 (Fallon (LORAN))
Fox Harbour Canada Labrador East Coast (GRI 7270)/ Canadian East Coast (GRI 5930) 52°22′35.252″N 55°42′27.862″W / 52.37645889°N 55.70773944°W / 52.37645889; -55.70773944 (Fox Harbour (LORAN))
George, Washington United States Canadian West Coast (GRI 5990)/ U.S. West Coast (GRI 9940) 47°03′48.096″N 119°44′38.976″W / 47.06336000°N 119.74416000°W / 47.06336000; -119.74416000 (George (LORAN))
Gesashi Japan East Asia (GRI 9930)/ North West Pacific (GRI 8930)
Gillette, Wyoming United States South Central U.S. (GRI 9610)/ North Central U.S. (GRI 8290) 44°00′11.305″N 105°37′23.895″W / 44.00314028°N 105.62330417°W / 44.00314028; -105.62330417 (Gillette (LORAN))
Grangeville, Louisiana United States South Central U.S. (GRI 9610)/ Southeast U.S. (GRI 7980) 30°43′33.149″N 090°49′43.046″W / 30.72587472°N 90.82862389°W / 30.72587472; -90.82862389 (Grangeville (LORAN))
Havre, Montana United States North Central U.S. (GRI 8290) 48°44′38.589″N 109°58′53.613″W / 48.74405250°N 109.98155917°W / 48.74405250; -109.98155917 (Havre (LORAN))
Hellissandur Iceland shut down on December 31, 1994 411.48 metre tall tower, now used for longwave broadcasting of RÚV on 189 kHz
Helong China China North Sea (GRI 7430)
Hexian China China South Sea (GRI 6780)
Jan Mayen Norway Bø (GRI 7001)/ Ejde (GRI 9007)
Johnston Island United States shut-down
Iwo Jima Japan shut down in September 1993, dismantled used a 411.48 metre tall tower
Jupiter, Florida United States Southeast U.S. (GRI 7980) 27°01′58.528″N 080°06′52.875″W / 27.03292444°N 80.11468750°W / 27.03292444; -80.11468750 (Jupiter (LORAN))
Kargaburan Turkey Mediterranean Sea (GRI 7990); shut down
Kwang Ju South Korea East Asia (GRI 9930) 35°2′24″N 126°32′27″E / 35.04000°N 126.54083°E / 35.04000; 126.54083 (Kwang Ju (LORAN))
Lampedusa Italy Mediterranean Sea (GRI 7990); shut down
Las Cruces, New Mexico United States South Central U.S. (GRI 9610) 32°4′18″N 106°52′4″W / 32.07167°N 106.86778°W / 32.07167; -106.86778 (Las Cruces (LORAN))
Lessay France Lessay (GRI 6731) / Sylt (GRI 7499)
Loop Head Ireland was planned (GRI 6731 and 9007), but never operational
Malone, Florida United States Great Lakes (GRI 8970) / Southeast U.S. (GRI 7980) 30°59′38.870″N 085°10′08.751″W / 30.99413056°N 85.16909750°W / 30.99413056; -85.16909750 (Malone (LORAN))
Minamitorishima Japan North West Pacific (GRI 8930) used until 1985 a 411.48 metre tall tower
Nantucket, Massachusetts United States Canadian East Coast (GRI 5930) / Northeast U.S. (GRI 9960) 41°15′12″N 69°58′39″W / 41.25333°N 69.97750°W / 41.25333; -69.97750 (Nantucket (LORAN))
Narrow Cape, Alaska United States North Pacific (GRI 9990) / Gulf of Alaska (GRI 7960) 57°26′20″N 152°22′11″W / 57.43889°N 152.36972°W / 57.43889; -152.36972 (Narrow Cape (LORAN))
Niijima Japan North West Pacific (GRI 8930) / East Asia (GRI 9930) 34°24′12″N 139°16′19″E / 34.40333°N 139.27194°E / 34.40333; 139.27194 (Niijima (LORAN))
Patpur India Calcutta (GRI 5543)
Pohang South Korea North West Pacific (GRI 8930) / East Asia (GRI 9930) 36°11′5″N 129°20′27″E / 36.18472°N 129.34083°E / 36.18472; 129.34083 (Pohang (LORAN))
Port Clarence, Alaska United States Gulf of Alaska (GRI 7960)/North Pacific (GRI 9990) uses a 411.48 metre tall tower 65°14′40.372″N 166°53′11.996″W / 65.24454778°N 166.88666556°W / 65.24454778; -166.88666556 (Port Clarence (LORAN))
Port Hardy Canada Canadian West Coast (GRI 5990) 50°36′29.830″N 127°21′28.489″W / 50.60828611°N 127.35791361°W / 50.60828611; -127.35791361 (Port Hardy (LORAN))
Rantum Germany Sylt (GRI 7499)/ Lessay (GRI 6731)
Raymondville, Texas United States South Central U.S. (GRI 9610)/ Southeast U.S. (GRI 7980) 26°31′55″N 97°50′0″W / 26.53194°N 97.83333°W / 26.53194; -97.83333 (Raymondville (LORAN))
Raoping China China South Sea (GRI 6780)/ China East Sea (GRI 8930) 23°43′26″N 116°53′45″E / 23.72389°N 116.89583°E / 23.72389; 116.89583 (Raoping (LORAN))
Rongcheng China China North Sea (GRI 7430)/ China East Sea (GRI 8930) 37°3′52″N 122°19′26″E / 37.06444°N 122.32389°E / 37.06444; 122.32389 (Rongcheng (LORAN))
Rugby UK experimental (GRI 6731); shut down at the end of July 2007
Saint Paul, Alaska United States North Pacific (GRI 9990) 57°09′12.350″N 170°15′06.245″W / 57.15343056°N 170.25173472°W / 57.15343056; -170.25173472 (Saint Paul (LORAN))
Salwa Saudi Arabia Saudi Arabia North (GRI 8830)/Saudi Arabia South (GRI 7030)
Searchlight, Nevada United States U.S. West Coast (GRI 9940)/South Central U.S. (GRI 9610) 35°19′18.305″N 114°48′16.881″W / 35.32175139°N 114.80468917°W / 35.32175139; -114.80468917 (Searchlight (LORAN))
Sellia Marina Italy Mediterranean Sea (GRI 7990); shut down 38°52′21″N 16°43′7″E / 38.87250°N 16.71861°E / 38.87250; 16.71861 (Sellia Marina (LORAN))
Seneca, New York United States Great Lakes (GRI 8970)/Northeast U.S. (GRI 9960) 42°42′51″N 76°49′33″W / 42.71417°N 76.82583°W / 42.71417; -76.82583 (Seneca (LORAN))
Shoal Cove, Alaska United States Canadian West Coast (GRI 5990)/Gulf of Alaska (GRI 7960) 55°26′21″N 131°15′19″W / 55.43917°N 131.25528°W / 55.43917; -131.25528 (Shoal Cove (LORAN))
Soustons France Lessay (GRI 6731) 43°44′23″N 1°22′50″W / 43.73972°N 1.38056°W / 43.73972; -1.38056 (Soustons (LORAN))
Tok, Alaska United States Gulf of Alaska (GRI 7960) 63°19′42.884″N 142°48′31.346″W / 63.32857889°N 142.80870722°W / 63.32857889; -142.80870722 (Tok (LORAN))
Tokachibuto Japan Eastern Russia Chayka (GRI 7950)/ North West Pacific (GRI 8930) 42°44′37″N 143°43′10″E / 42.74361°N 143.71944°E / 42.74361; 143.71944 (Tokachibuto (LORAN))
Upolo Point, Hawaii United States shut-down
Værlandet Norway Sylt (GRI 7499)/ Ejde (GRI 9007)
Veraval India Bombay (GRI 6042) 20°57′7″N 70°20′13″E / 20.95194°N 70.33694°E / 20.95194; 70.33694 (Veraval (LORAN))
Williams Lake Canada Canadian West Coast (GRI 5990) 51°57′58.876″N 122°22′01.686″W / 51.96635444°N 122.36713500°W / 51.96635444; -122.36713500 (Williams Lake (LORAN))
Xuancheng China China North Sea (GRI 7430)/ China East Sea (GRI 8930)
Yap Micronesia shut down in 1987, dismantled used a 304.8 metre tall tower


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انظر أيضاً

الهامش

  1. ^ "Electronic Position Fixing System" (PDF). Admiralty Notices to Mariners. United Kingdom Hydrographic Office (26/07). 2007-06-28. Retrieved 2008-01-19. Cite has empty unknown parameter: |coauthors= (help); Check date values in: |date= (help)
  • Jennet Conant, Tuxedo Park: A Wall Street Tycoon and the Secret Palace of Science That Changed the Course of World War II (New York: Simon & Schuster, 2002, ISBN 0-684-87287-0) pp. 231-232.
  • Department of Transportation and Department of Defense (2006-02). "2005 Federal Radionavigation Plan" (PDF). Retrieved 2006-02-26. Cite has empty unknown parameter: |accessyear= (help); Check date values in: |year= (help)

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