GPS - Revision history

Maku at 11:47, 9 March 2010

2010-03-09T11:47:15Z

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	* [http://www.globallocate.com Global Locate] Host-based A-[[Navigation System\|GPS]] embedded in devices such as [[HP\|HP]] iPAQ		* [http://www.globallocate.com Global Locate] Host-based A-[[Navigation System\|GPS]] embedded in devices such as [[HP\|HP]] iPAQ
	*[http://www.oscilloquartz.com/ [[Navigation System\|GPS]]-based Synchronization and Time Server solutions] [[Navigation System\|GPS]]-based solutions for all telecom and timing Synchronisation needs		*[http://www.oscilloquartz.com/ [[Navigation System\|GPS]]-based Synchronization and Time Server solutions] [[Navigation System\|GPS]]-based solutions for all telecom and timing Synchronisation needs
			*[http://www.meinberg.de/english/products/ntp-time-server.htm NTP Server Appliances] Reliable NTP Time Server appliances
	*[http://www.galleon.eu.com/products/ts.htm [[Navigation System\|GPS]] Time Server solutions] Time Server solutions for all your computer time Synchronisation needs		*[http://www.galleon.eu.com/products/ts.htm [[Navigation System\|GPS]] Time Server solutions] Time Server solutions for all your computer time Synchronisation needs
	* [http://www.isrfleettrack.com/products/hardware.html ISR FleetTrack Silent Position Monitor] The hardware component of ISR's total fleet tracking suite.		* [http://www.isrfleettrack.com/products/hardware.html ISR FleetTrack Silent Position Monitor] The hardware component of ISR's total fleet tracking suite.

Red marquis at 10:45, 30 January 2009

2009-01-30T10:45:47Z

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	~~{{Cleanup}}~~
	The '''Global Positioning System''', usually called '''GPS''', is the only fully-functional satellite navigation system. A constellation of more than two dozen GPS satellites broadcasts precise timing signals by radio to GPS receivers, allowing them to accurately determine their location (longitude, latitude, and altitude) in any weather, day or night, anywhere on Earth.		The '''Global Positioning System''', usually called '''GPS''', is the only fully-functional satellite navigation system. A constellation of more than two dozen GPS satellites broadcasts precise timing signals by radio to GPS receivers, allowing them to accurately determine their location (longitude, latitude, and altitude) in any weather, day or night, anywhere on Earth.

Red marquis: /* GPS jamming */

2009-01-30T10:45:21Z

GPS jamming

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	==[[Navigation System\|GPS]] jamming==		==[[Navigation System\|GPS]] jamming==

	Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>		Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>Space Environment Center. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>

	[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from Russia, their effectiveness is in question following their use in the Iraq war. The U.S. government believes that such jammers were also used occasionally during the U.S. invasion of Afghanistan. Some officials believe that jammers could be used to attract the precision-guided munitions towards non-combatant infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [nti-radiation missiles. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. March 25, 2003.</ref>		[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from Russia, their effectiveness is in question following their use in the Iraq war. The U.S. government believes that such jammers were also used occasionally during the U.S. invasion of Afghanistan. Some officials believe that jammers could be used to attract the precision-guided munitions towards non-combatant infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [nti-radiation missiles. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. March 25, 2003.</ref>

Red marquis: /* History */

2009-01-30T10:45:01Z

History

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	By 1985, ten more experimental Block-I satellites had been launched to validate the concept. The first modern Block-II satellite was launched on 14th February 1989, and a complete constellation of 24 satellites was in orbit by 17th January 1994.		By 1985, ten more experimental Block-I satellites had been launched to validate the concept. The first modern Block-II satellite was launched on 14th February 1989, and a complete constellation of 24 satellites was in orbit by 17th January 1994.

	In 1996, recognizing the importance of [[Navigation System\|GPS]] to civilian users as well as military users, President Bill Clinton issued a policy directive<ref>[[National Archives and Records Administration]]. [http://clinton4.nara.gov/textonly/WH/EOP/OSTP/html/[[Navigation System\|gps]]-factsheet.html U.S. GLOBAL POSITIONING SYSTEM POLICY]. March 29, 1996.</ref> declaring [[Navigation System\|GPS]] to be a dual-use system and establishing an Interagency [[Navigation System\|GPS]] Executive Board to manage it as a national asset.		In 1996, recognizing the importance of [[Navigation System\|GPS]] to civilian users as well as military users, President Bill Clinton issued a policy directive<ref>National Archives and Records Administration. [http://clinton4.nara.gov/textonly/WH/EOP/OSTP/html/[[Navigation System\|gps]]-factsheet.html U.S. GLOBAL POSITIONING SYSTEM POLICY]. March 29, 1996.</ref> declaring [[Navigation System\|GPS]] to be a dual-use system and establishing an Interagency [[Navigation System\|GPS]] Executive Board to manage it as a national asset.

	In 1998, Vice President Al Gore announced plans to upgrade [[Navigation System\|GPS]] with two new civilian signals for enhanced user accuracy and reliability, particularly with respect to aviation safety.		In 1998, Vice President Al Gore announced plans to upgrade [[Navigation System\|GPS]] with two new civilian signals for enhanced user accuracy and reliability, particularly with respect to aviation safety.

Red marquis: /* Techniques to improve GPS accuracy */

2009-01-30T10:44:04Z

Techniques to improve GPS accuracy

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	The accuracy of [[Navigation System\|GPS]] can be improved in a number of ways:		The accuracy of [[Navigation System\|GPS]] can be improved in a number of ways:

	* '''[[Differential GPS]]''' '''(DGPS)''' can improve the normal [[Navigation System\|GPS]] accuracy of 4-20 meters to 1-3 meters.<ref>[[Federal Highway Administration]]. [http://www.tfhrc.gov/its/ndgps/02072.htm Nationwide DGPS Program Fact Sheet]. Accessed May 14, 2006</ref> DGPS uses a network of stationary [[Navigation System\|GPS]] receivers to calculate the difference between their actual known position and the position as calculated by their received [[Navigation System\|GPS]] signal. The "difference" is broadcast as a local FM signal, allowing many civilian [[Navigation System\|GPS]] receivers to "fix" the signal for greatly improved accuracy.		* '''[[Differential GPS]]''' '''(DGPS)''' can improve the normal [[Navigation System\|GPS]] accuracy of 4-20 meters to 1-3 meters.<ref>Federal Highway Administration. [http://www.tfhrc.gov/its/ndgps/02072.htm Nationwide DGPS Program Fact Sheet]. Accessed May 14, 2006</ref> DGPS uses a network of stationary [[Navigation System\|GPS]] receivers to calculate the difference between their actual known position and the position as calculated by their received [[Navigation System\|GPS]] signal. The "difference" is broadcast as a local FM signal, allowing many civilian [[Navigation System\|GPS]] receivers to "fix" the signal for greatly improved accuracy.
	* The Wide Area Augmentation System ('''WAAS'''). This uses a series of ground reference stations to calculate [[Navigation System\|GPS]] correction messages, which are uploaded to a series of additional satellites in geosynchronous orbit for transmission to [[Navigation System\|GPS]] receivers, including information on ionospheric delays, individual satellite clock drift, and suchlike. Although only a few WAAS satellites are currently available as of 2004, it is hoped that eventually WAAS will provide sufficient reliability and accuracy that it can be used for critical applications such as [[Navigation System\|GPS]]-based instrument approaches in aviation (landing an airplane in conditions of little or no visibility). The current WAAS system only works for North America (where the reference stations are located), and due to the satellite location the system is only generally usable in the eastern and western coastal regions. However, variants of the WAAS system are being developed in Europe (EGNOS, the Euro Geostationary [[Navigation System\|Navigation]] Overlay Service), and Japan ('''MSAS''', the Multi-Functional Satellite Augmentation System), which are virtually identical to WAAS.		* The Wide Area Augmentation System ('''WAAS'''). This uses a series of ground reference stations to calculate [[Navigation System\|GPS]] correction messages, which are uploaded to a series of additional satellites in geosynchronous orbit for transmission to [[Navigation System\|GPS]] receivers, including information on ionospheric delays, individual satellite clock drift, and suchlike. Although only a few WAAS satellites are currently available as of 2004, it is hoped that eventually WAAS will provide sufficient reliability and accuracy that it can be used for critical applications such as [[Navigation System\|GPS]]-based instrument approaches in aviation (landing an airplane in conditions of little or no visibility). The current WAAS system only works for North America (where the reference stations are located), and due to the satellite location the system is only generally usable in the eastern and western coastal regions. However, variants of the WAAS system are being developed in Europe (EGNOS, the Euro Geostationary [[Navigation System\|Navigation]] Overlay Service), and Japan ('''MSAS''', the Multi-Functional Satellite Augmentation System), which are virtually identical to WAAS.
	* A Local Area Augmentation System ('''LAAS'''). This is similar to WAAS, in that similar correction data are used. But in this case, the correction data are transmitted from a local source, typically at an airport or another location where accurate positioning is needed. These correction data are typically useful for only about a thirty to fifty kilometer radius around the transmitter.		* A Local Area Augmentation System ('''LAAS'''). This is similar to WAAS, in that similar correction data are used. But in this case, the correction data are transmitted from a local source, typically at an airport or another location where accurate positioning is needed. These correction data are typically useful for only about a thirty to fifty kilometer radius around the transmitter.

Red marquis: /* References */

2009-01-30T10:43:44Z

References

Red marquis: /* See also */

2009-01-30T10:42:45Z

Red marquis: /* Other systems */

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Other systems

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	== Other systems ==		== Other systems ==
	Russia operates an independent system called [[GLONASS]] ('''glo'''bal '''na'''vigation '''s'''ystem), although with only twelve active satellites [[as of 2004]], the system is of limited usefulness. There are plans to restore GLONASS to full operation by 2008. The [[European Union]] is developing [[Galileo ~~positioning system\|Galileo]]~~ as an alternative to [[Navigation System\|GPS]], planned to be in operation by 2010. China and France are also developing ~~[[satellite navigation system\|~~other satellite navigation systems]].		Russia operates an independent system called GLONASS ('''glo'''bal '''na'''vigation '''s'''ystem), although with only twelve active satellites as of 2004, the system is of limited usefulness. There are plans to restore GLONASS to full operation by 2008. The European Union is developing Galileo as an alternative to [[Navigation System\|GPS]], planned to be in operation by 2010. China and France are also developing other satellite navigation systems.

	~~{{[[Navigation System\|GPS]]}}~~

	==See also==		==See also==

Red marquis: /* GPS jamming */

2009-01-30T10:41:39Z

GPS jamming

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	Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>		Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>

	[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from [[Russia]], their effectiveness is in question following their use in the Iraq war. The ~~[[Federal government of the United States\|~~U.S. government]] believes that such jammers were also used occasionally during the ~~[[United States invasion of Afghanistan\|~~U.S. invasion of Afghanistan]]. Some officials believe that jammers could be used to attract the precision-guided munitions towards [[non-combatant]] infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [~~[anti~~-radiation ~~missile]]s~~. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. [[March 25]], [[2003]].</ref>		[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from Russia, their effectiveness is in question following their use in the Iraq war. The U.S. government believes that such jammers were also used occasionally during the U.S. invasion of Afghanistan. Some officials believe that jammers could be used to attract the precision-guided munitions towards non-combatant infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [nti-radiation missiles. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. March 25, 2003.</ref>

	== Other systems ==		== Other systems ==

Red marquis: /* GPS jamming */

2009-01-30T10:40:56Z

GPS jamming

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	==[[Navigation System\|GPS]] jamming==		==[[Navigation System\|GPS]] jamming==
	~~{{further\|[[SAASM\|Selective Availability / Anti-Spoofing Module]]}}~~

	Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. [[January 1]], [[2003]].</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. [[February 12]], [[2003]].</ref> ~~[[RAIM\|~~Receiver Autonomous Integrity Monitoring ]](RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural [[geomagnetic ~~storm]]s~~, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. [[August 26]], [[1996]].</ref>		Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>

	[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from [[Russia]], their effectiveness is in question following their use in the Iraq war. The [[Federal government of the United States\|U.S. government]] believes that such jammers were also used occasionally during the [[United States invasion of Afghanistan\|U.S. invasion of Afghanistan]]. Some officials believe that jammers could be used to attract the precision-guided munitions towards [[non-combatant]] infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [[anti-radiation missile]]s. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. [[March 25]], [[2003]].</ref>		[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from [[Russia]], their effectiveness is in question following their use in the Iraq war. The [[Federal government of the United States\|U.S. government]] believes that such jammers were also used occasionally during the [[United States invasion of Afghanistan\|U.S. invasion of Afghanistan]]. Some officials believe that jammers could be used to attract the precision-guided munitions towards [[non-combatant]] infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [[anti-radiation missile]]s. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. [[March 25]], [[2003]].</ref>

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	==[[Navigation System\|GPS]] jamming==		==[[Navigation System\|GPS]] jamming==

	Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>		Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>Space Environment Center. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>

	[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from Russia, their effectiveness is in question following their use in the Iraq war. The U.S. government believes that such jammers were also used occasionally during the U.S. invasion of Afghanistan. Some officials believe that jammers could be used to attract the precision-guided munitions towards non-combatant infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [nti-radiation missiles. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. March 25, 2003.</ref>		[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from Russia, their effectiveness is in question following their use in the Iraq war. The U.S. government believes that such jammers were also used occasionally during the U.S. invasion of Afghanistan. Some officials believe that jammers could be used to attract the precision-guided munitions towards non-combatant infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [nti-radiation missiles. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. March 25, 2003.</ref>

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	Russia operates an independent system called GLONASS ('''glo'''bal '''na'''vigation '''s'''ystem), although with only twelve active satellites as of 2004, the system is of limited usefulness. There are plans to restore GLONASS to full operation by 2008. The European Union is developing Galileo as an alternative to [[Navigation System\|GPS]], planned to be in operation by 2010. China and France are also developing other satellite navigation systems.		Russia operates an independent system called GLONASS ('''glo'''bal '''na'''vigation '''s'''ystem), although with only twelve active satellites as of 2004, the system is of limited usefulness. There are plans to restore GLONASS to full operation by 2008. The European Union is developing Galileo as an alternative to [[Navigation System\|GPS]], planned to be in operation by 2010. China and France are also developing other satellite navigation systems.

	~~==See also==~~
	~~{{commonscat\|Global Positioning System}}~~
	*[[Geographic coordinate system]]
	*[[Wikipedia:WikiProject Geographical coordinates\|Wikipedia Geographical coordinates project]] - adding [[Geographic coordinate system\|geographic coordinates]] to WikiPedia articles
	*[[Assisted GPS]]
	*[http://confluence.org Degree confluence project] Use [[Navigation System\|GPS]] to visit integral degrees of latitude and longitude. Pictures and narrative for each one.
	*[[Geodashing]]
	*[[GPX]] - [[Navigation System\|GPS]] eXchange Format
	*[[Location based media]]
	*[[Waypoint]]
	*[[m:WikiGPS\|WikiGPS]], [[Wikimedia Foundation\|Wikimedia]] proposed project.
	*[[World Geodetic System]] - '''WGS 84''' defines a global reference frame for [[Navigation System\|GPS]]

	==External links==		==External links==

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	==[[Navigation System\|GPS]] jamming==		==[[Navigation System\|GPS]] jamming==
	~~{{further\|[[SAASM\|Selective Availability / Anti-Spoofing Module]]}}~~

	Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. [[January 1]], [[2003]].</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. [[February 12]], [[2003]].</ref> ~~[[RAIM\|~~Receiver Autonomous Integrity Monitoring ]](RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural [[geomagnetic ~~storm]]s~~, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. [[August 26]], [[1996]].</ref>		Jamming of any radio [[Navigation System\|navigation system]], including satellite based [[Navigation System\|navigation]], is possible. The U.S. Air Force conducted [[Navigation System\|GPS]] jamming exercises in 2003 and they also have [[Navigation System\|GPS]] anti-spoofing capabilities. In 2002, a detailed description of how to build a short range [[Navigation System\|GPS]] L1 C/A jammer was posted on a hackers' site by an anonymous author. There has also been at least one well-documented case of unintentional jamming, it traced back to a malfunctioning TV antenna preamplifier.<ref>[[Navigation System\|GPS]] World. [http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=43404&&pageID=1 The hunt for an unintentional [[Navigation System\|GPS]] jammer]. January 1, 2003.</ref> If stronger signals were generated intentionally, they could potentially interfere with aviation [[Navigation System\|GPS]] receivers within line of sight. According to John Ruley, of AVweb, "IFR pilots should have a fallback plan in case of a [[Navigation System\|GPS]] malfunction".<ref>Ruley, John. AVweb. [http://www.avweb.com/news/avionics/182754-1.html [[Navigation System\|GPS]] jamming]. February 12, 2003.</ref> Receiver Autonomous Integrity Monitoring (RAIM), a feature of some aviation and marine receivers, is designed to provide a warning to the user if jamming or another problem is detected. There are also incidents of unintentional jamming, [[Navigation System\|GPS]] signals can also be interfered with by natural geomagnetic storms, predominantly at high latitudes.<ref>[[Space Environment Center]]. [http://www.sec.noaa.gov/nav/[[Navigation System\|gps]].html SEC [[Navigation System\|Navigation]] Systems [[Navigation System\|GPS]] Page]. August 26, 1996.</ref>

	[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from [[Russia]], their effectiveness is in question following their use in the Iraq war. The [[Federal government of the United States\|U.S. government]] believes that such jammers were also used occasionally during the [[United States invasion of Afghanistan\|U.S. invasion of Afghanistan]]. Some officials believe that jammers could be used to attract the precision-guided munitions towards [[non-combatant]] infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [[anti-radiation missile]]s. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. [[March 25]], [[2003]].</ref>		[[Navigation System\|GPS]] jammers the size of a cigarette box are allegedly available from [[Russia]], their effectiveness is in question following their use in the Iraq war. The [[Federal government of the United States\|U.S. government]] believes that such jammers were also used occasionally during the [[United States invasion of Afghanistan\|U.S. invasion of Afghanistan]]. Some officials believe that jammers could be used to attract the precision-guided munitions towards [[non-combatant]] infrastructure, other officials believe that the jammers are completely ineffective. In either case, the jammers may be attractive targets for [[anti-radiation missile]]s. Low power jammers would have limited military usefulness and high power jammers would be easy to locate and destroy. During the Iraq war, the US military claimed to destroy a [[Navigation System\|GPS]] jammer with a [[Navigation System\|GPS]]-guided bomb. <ref>American Forces Press Service. [http://www.defenselink.mil/news/Mar2003/n03252003_200303254.html CENTCOM charts progress]. [[March 25]], [[2003]].</ref>

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	===References===		===References===
	<references/>		<references/>
	~~<!--See [[Wikipedia:Footnotes]] for an explanation of how to generate footnotes using the <ref(erences/)> tags-->~~
	* [http://www.colorado.edu/geography/gcraft/notes/[[Navigation System\|gps]]/[[Navigation System\|gps]]_f.html Peter H. Dana: Global Positioning System Overview] - Large amount of technical information and discussion.		* [http://www.colorado.edu/geography/gcraft/notes/[[Navigation System\|gps]]/[[Navigation System\|gps]]_f.html Peter H. Dana: Global Positioning System Overview] - Large amount of technical information and discussion.
	* [http://www.navcen.uscg.gov/pubs/[[Navigation System\|gps]]/sigspec/default.htm [[Navigation System\|GPS]] SPS Signal Specification, 2nd Edition] - The official (civilian) signal specification.		* [http://www.navcen.uscg.gov/pubs/[[Navigation System\|gps]]/sigspec/default.htm [[Navigation System\|GPS]] SPS Signal Specification, 2nd Edition] - The official (civilian) signal specification.
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	* [http://gpsinformation.net/airgps/gpsrfi.htm Is it Safe to use a handheld [[Navigation System\|GPS]] Receiver on a Commercial Aircraft?] - Discusses the safety of personal use of a [[Navigation System\|GPS]] on commercial aircraft.		* [http://gpsinformation.net/airgps/gpsrfi.htm Is it Safe to use a handheld [[Navigation System\|GPS]] Receiver on a Commercial Aircraft?] - Discusses the safety of personal use of a [[Navigation System\|GPS]] on commercial aircraft.
	* [http://netlab18.cis.nctu.edu.tw/html/paper/2001_11_06/Challenges%20in%20bringing%20[[Navigation System\|GPS]]%20to%20Mainstream%20Consumers.pdf The Global Positioning System: Challenges in Bringing [[Navigation System\|GPS]] to Mainstream Consumers] Technical Article by Kanwar Chadha, BSEE (1998)		* [http://netlab18.cis.nctu.edu.tw/html/paper/2001_11_06/Challenges%20in%20bringing%20[[Navigation System\|GPS]]%20to%20Mainstream%20Consumers.pdf The Global Positioning System: Challenges in Bringing [[Navigation System\|GPS]] to Mainstream Consumers] Technical Article by Kanwar Chadha, BSEE (1998)
	* [http://www.navcen.uscg.gov/[[Navigation System\|gps]]/default.htm USCG [[Navigation System\|Navigation]] Center]: Status of the [[Navigation System\|GPS]] constellation, government policy, and links to other references. Also includes satellite [[almanac]] data.		* [http://www.navcen.uscg.gov/[[Navigation System\|gps]]/default.htm USCG [[Navigation System\|Navigation]] Center]: Status of the [[Navigation System\|GPS]] constellation, government policy, and links to other references. Also includes satellite almanac data.
	* [https://www.schriever.af.mil/[[Navigation System\|gps]]/archive/2005/ Schriever Airforce Base Webserver]: Even more up-to-date almanac data and NANUs		* [https://www.schriever.af.mil/[[Navigation System\|gps]]/archive/2005/ Schriever Airforce Base Webserver]: Even more up-to-date almanac data and NANUs
	* [http://pnt.gov/ National Space-Based PNT Executive Committee] - Established in 2004 to oversee management of [[Navigation System\|GPS]] and [[Navigation System\|GPS]] augmentations at a national level.		* [http://pnt.gov/ National Space-Based PNT Executive Committee] - Established in 2004 to oversee management of [[Navigation System\|GPS]] and [[Navigation System\|GPS]] augmentations at a national level.
	* [http://[[Navigation System\|gps]].losangeles.af.mil/ The [[Navigation System\|GPS]] Joint Program Office ([[Navigation System\|GPS]] JPO)] - Responsible for designing and acquiring the system on behalf of the US Government.		* [http://[[Navigation System\|gps]].losangeles.af.mil/ The [[Navigation System\|GPS]] Joint Program Office ([[Navigation System\|GPS]] JPO)] - Responsible for designing and acquiring the system on behalf of the US Government.
	* The ~~[[Federal Aviation Administration\|~~FAA]] has more information on [[Navigation System\|GPS]], WAAS, LAAS, and DGPS at http://[[Navigation System\|gps]].faa.gov/FAQ/index.htm		* The FAA has more information on [[Navigation System\|GPS]], WAAS, LAAS, and DGPS at http://[[Navigation System\|gps]].faa.gov/FAQ/index.htm
	* [http://www.defense-update.com/products/g/[[Navigation System\|gps]]-guidance.htm [[Navigation System\|GPS]] Weapon Guidance Techniques]		* [http://www.defense-update.com/products/g/[[Navigation System\|gps]]-guidance.htm [[Navigation System\|GPS]] Weapon Guidance Techniques]