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[[Image:LAAS Architecture.svg|thumb|300px|LAAS architecture, similar in concept to JPALS LDGPS fixed base category]]
[[Image:LAAS_Architecture.png|right|thumb|LAAS Architecture]]
TheIn the [[United States Armed Forces]], the '''Jointjoint Precisionprecision Approachapproach and Landinglanding Systemsystem''' ('''JPALS)''') is a military,an all-weather system for precision guidance of landing systemaircraft. It is based on real-time differential correction of the [[Global Positioning System|GPS]] (GPS) signal, augmented with a local area correction message, and transmitted to the user via secure means. It Theis onboardused receiveron comparesterrestrial theairfields currentas GPS-derivedwell position withas the local[[US correctionNavy]]'s signal,[[amphibious derivingassault aship]]s highly-accurateand three-dimensional position capable[[List of beingaircraft usedcarriers forof all-weatherthe approachesUnited viaStates anNavy|aircraft carriers]] ([[InstrumentHull Landingclassification Systemsymbol|ILShull classifications]]-style display.LH and JPALSCVN, isrespectively). a form of differential GPS..
The onboard receiver compares the current GPS-derived position with the local correction signal, deriving a highly accurate three-dimensional position capable of being used for all-weather approaches via an [[Instrument Landing System]]-style display. Accuracy, while classified, is believed to be about 1 m or better. While JPALS is similar to [[Local Area Augmentation System]], but intended primarily for use by the military, some elements of JPALS may eventually see their way into civilian use to help protect high-value civilian operations against unauthorized signal alteration.
==History==
[[Image:JPALS Tactical Prototype.jpg|250px|thumb|JPALS tactical prototype]]
The needdevelopment forof JPALS was identifiedthe inresult response toof two factors.main military requirements. First, the military needs aan highlyall-service, highly mobile all-weather precision approach system, tailorable to a wide range of environments, from shipboard use to rapid installation at austeremakeshift airfields. Second, they need a robust system that maintainscan maintain a high level of reliancereliability in combat operations, particularly, onein that'sits highlyability resistantto toeffectively resist jamming.
==Operation==
JPALS falls intoencompasses two main categories,: SRGPS (shipboard relative [[GPS]]) and LDGPS (land/local differential GPS). SRGPS provides highly- accurate approach positioning for operations aboard ship, including aircraft carriers, helo and SSTO/VTOLVL carriers, and other shipboard operations, primarily involving helicopter operations.
LDGPS is further divided into three sub-categories: fixed Fixed Basebase, Tacticaltactical, and Specialspecial Missionsmissions. Fixed Basebase is used for ongoing operations at military airfields around the world, while the Tacticaltactical system is a portable system, designed for relatively short-term, austere airfield operations. The systemspecial designedmissions for Special Missionssystem is more than justa highly mobileportable - it's portable,system capable of rapid installation and use by [[special forces]].
==Accuracy==
The accuracy of LAAS,[[local Localarea Areaaugmentation Augmentationsystem]] System,(LAAS) is better than [[Instrument Landing System#ILS categories|CAT III ILS]] accuracy, and will provide horizontal and vertical resolutions of less than 1 m. Although the exact accuracy of JPALS will remain classified, it's estimated that JPALS will meet or exceed this accuracy for authorized users.
It's estimated that JPALS will meet or exceed this accuracy for authorized users.
==Benefits==
The main benefit of JPALS is that it's a system that can be taken anywhere, anytime, providing a safe and effective way to conduct 24/7, all-weather, anti-jam instrument landing system capability to all authorized users, worldwide. A secondary benefit is a significant reduction in cost over current systems.
The naval version of JPALS transmits a signal that has a low probability of intercept; so it is unlikely that an enemy will detect the signal and trace it back to its source. The existing system, [[tactical air navigation]] (TACAN), is not encrypted or concealed in any way, which can reveal the ___location of the ship on which it is installed. This is not acceptable in [[EMCON|emissions control]] (EMCON) or stealth conditions.
A secondary benefit is a significant reduction in cost savings over current systems, currently available only to larger, more permanent military installations.
The increasesincrease in both accuracy and reliability will significantly enhance operations while reducing non-operational periods due to weather or adversarial efforts.
==See also==
*[[Local Areaarea Augmentationaugmentation Systemsystem]] is a similar system for civilian usage. ▼*[[Wide area augmentation system]]
*[[Instrument Landinglanding Systemsystem]] ▼*[[Global Positioning System]]
*[[Differential GPS]]
*[[GlobalMicrowave Positioninglanding Systemsystem]]
*[[Electronics_Technician_(United_States_Navy)|Electronics technician]]
▲*[[Instrument Landing System]]
▲*[[Local Area Augmentation System]] is a similar system for civilian usage.
*[[Wide Area Augmentation System]] ▼
{{GPS}}
* {{note|FAA_FS}}{{cite web ▼
| author=Federal Aviation Administration (FAA) ▼ | yeardate=February 27, 2004 ▼▲* {{note|FAA_FS}}{{cite web
| url=http://gps.faa.gov/Library/laas-f-text.htm ▼▲ | author=Federal Aviation Administration (FAA)
▲*[[Wide |title=Local Area Augmentation System ]] (LAAS) Fact Sheet
▲ | year=February 27, 2004
| accessdate=November 20 , 2005 ▼▲ | url=http://gps.faa.gov/Library/laas-f-text.htm
|archiveurl=https://web.archive.org/web/20060118032723/http://gps.faa.gov/Library/laas-f-text.htm
| title=Local Area Augmentation System (LAAS) Fact Sheet
|archivedate=January 18, 2006
| format=
|url-status=dead
| work=
}}
| publisher=
* {{note|FRP2001}} {{cite web ▼▲ | accessdate=November 20
| accessyear=2005}}
▲* {{note|FRP2001}} {{cite web
| author=Department of Transportation and Department of Defense
| yeardate=March 25, 2002
| url=http://www.navcen.uscg.gov/pubspdf/frp/frp2001/FRP2001.pdf
| title=2001 Federal Radionavigation Plan
| format=PDF
| work=
| publisher=
| accessdate=November 27, 2005
}}
| accessyear=2005}}
* IHS Aerospace - Honeywell (July 7, 2005). [http://aero.ihs.com/news-05Q3/honeywell-laas-update.jsp Honeywell to Update Local Area Augmentation System (LAAS) Prototype.] Press Release.
===External links===
* [http://gpswww.faa.gov/Programsabout/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/index.htm FAA GPS Programs]
* [http://gpswww.faa.gov/Libraryabout/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/laas-f-text.htm/ FAA LAAS Fact Sheet]
* [http://waas.stanford.edu/research/jpals.htm Stanford JPALS Page] {{Webarchive|url=https://web.archive.org/web/20060427122246/http://waas.stanford.edu/research/jpals.htm |date=2006-04-27 }}
* [https://web.archive.org/web/20060311054600/http://www.raytheon.com/products/jpals/ Raytheon JPALS Product Page]
* [http://www.fas.org/man/dod-101/sys/ac/equip/jpals.htm FAS JPALS Page]
* [http://www.globalsecurity.org/military/systems/aircraft/systems/jpals.htm GlobalSecurity.org's JPALS Page]
* [https://web.archive.org/web/20140911053740/http://www.navair.navy.mil/index.cfm?fuseaction=home.displayPlatform&key=8559E3E9-42F1-4A08-876B-5F2E7FA6AAB2 US Navy information]
* [https://web.archive.org/web/20140911052320/http://www.navair.navy.mil/index.cfm?fuseaction=home.PhotoGalleryDetail&key=62593B59-C3A0-454F-8CA4-594D953A0005 US Navy images]
[[Category:{{Satellite navigation systems ]]}}▼
[[Category:Aircraft instrumentslanding systems]]
[[Category:Military aviation]]
[[Category:GPSGlobal Positioning System]]
▲[[Category:Satellite navigation systems]]
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