Availability - Revision history

Filipe.Pelica: Included editor logo.

2014-09-18T16:47:58Z

Included editor logo.

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	\|Level=Basic		\|Level=Basic
	\|YearOfPublication=2011		\|YearOfPublication=2011
			\|Logo=GMV
	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	}}		}}

Filipe.Pelica: fixed broken link

2014-05-29T11:03:27Z

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	The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.		The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.

	Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite (or slot<ref group="footnotes">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.~~pnt~~.gov/~~public~~/~~docs~~/2008~~/spsps2008~~.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.		Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite (or slot<ref group="footnotes">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.gps.gov/technical/ps/2008-SPS-performance-standard.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

	The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (for 2D positioning plus time).		The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (for 2D positioning plus time).

Filipe.Pelica: footnotes harmonizing

2014-01-10T17:02:37Z

footnotes harmonizing

← Older revision		Revision as of 17:02, 10 January 2014
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	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	}}		}}
	The availability of a navigation system is the percentage of time that the services of the system are usable by the navigator. Availability is an indication of the ability of the system to provide usable service within the specified coverage area. Signal availability is the percentage of time that navigation signals transmitted from external sources are available for use. It is a function of both the physical characteristics of the environment and the technical capabilities of the transmitter facilities{{#tag:ref\| This definition was adapted from the [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf 2008 US Federal Radionavigation Plan]<ref> [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf US Federal Radionavigation Plan], DOT-VNTSC-RITA-08-02/DoD-4650.5, 2008</ref>\|group="nb"}}.		The availability of a navigation system is the percentage of time that the services of the system are usable by the navigator. Availability is an indication of the ability of the system to provide usable service within the specified coverage area. Signal availability is the percentage of time that navigation signals transmitted from external sources are available for use. It is a function of both the physical characteristics of the environment and the technical capabilities of the transmitter facilities{{#tag:ref\| This definition was adapted from the [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf 2008 US Federal Radionavigation Plan]<ref> [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf US Federal Radionavigation Plan], DOT-VNTSC-RITA-08-02/DoD-4650.5, 2008</ref>\|group="footnotes"}}.


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	The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.		The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.

	Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite (or slot<ref group="nb">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.		Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite (or slot<ref group="footnotes">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

	The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (for 2D positioning plus time).		The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (for 2D positioning plus time).
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	==Notes==		==Notes==
	<references group="nb"/>		<references group="footnotes"/>
	==References==		==References==
	<references/>		<references/>

	[[Category:Fundamentals]]		[[Category:Fundamentals]]

Carlos.Lopez at 11:19, 23 February 2012

2012-02-23T11:19:12Z

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	{{Article Infobox2		{{Article Infobox2
	\|Category=Fundamentals		\|Category=Fundamentals
	\|~~Title={{PAGENAME}}~~		\|Editors=GMV
	~~\|Authors~~=GMV
	\|Level=Basic		\|Level=Basic
	\|YearOfPublication=2011		\|YearOfPublication=2011
	\|~~Logo~~=~~GMV~~		\|Title={{PAGENAME}}
	}}		}}


	The availability of a navigation system is the percentage of time that the services of the system are usable by the navigator. Availability is an indication of the ability of the system to provide usable service within the specified coverage area. Signal availability is the percentage of time that navigation signals transmitted from external sources are available for use. It is a function of both the physical characteristics of the environment and the technical capabilities of the transmitter facilities{{#tag:ref\| This definition was adapted from the [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf 2008 US Federal Radionavigation Plan]<ref> [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf US Federal Radionavigation Plan], DOT-VNTSC-RITA-08-02/DoD-4650.5, 2008</ref>\|group="nb"}}.		The availability of a navigation system is the percentage of time that the services of the system are usable by the navigator. Availability is an indication of the ability of the system to provide usable service within the specified coverage area. Signal availability is the percentage of time that navigation signals transmitted from external sources are available for use. It is a function of both the physical characteristics of the environment and the technical capabilities of the transmitter facilities{{#tag:ref\| This definition was adapted from the [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf 2008 US Federal Radionavigation Plan]<ref> [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf US Federal Radionavigation Plan], DOT-VNTSC-RITA-08-02/DoD-4650.5, 2008</ref>\|group="nb"}}.

Rui.Pereira at 13:45, 18 October 2011

2011-10-18T13:45:06Z

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	\|Category=Fundamentals		\|Category=Fundamentals
	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	\|Authors=~~Rui Barradas Pereira~~		\|Authors=GMV
	\|Level=Basic		\|Level=Basic
	\|YearOfPublication=2011		\|YearOfPublication=2011

Rui.Pereira at 15:43, 29 April 2011

2011-04-29T15:43:39Z

← Older revision		Revision as of 15:43, 29 April 2011
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	The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.		The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.

	Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite(or slot<ref group="nb">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.		Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite (or slot<ref group="nb">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

	The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (2D positioning plus time).		The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (for 2D positioning plus time).

	When considering the availability of a PVT additional constraints can be added to define when the system is available. If a specific application requires that a PVT is only usable if the error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if the system ~~support~~ integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.		When considering the availability of a PVT additional constraints can be added to define when the system is available. If a specific application requires that a PVT is only usable if the expected error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if the system supports integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.

	Availability can be influenced by several factors (see [[GNSS Performances]] for factors that influence the performance of GNSS) being the most important the constellation configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.		Availability can be influenced by several factors (see [[GNSS Performances]] for factors that influence the performance of GNSS) being the most important the constellation configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.

Rui.Pereira at 11:05, 14 April 2011

2011-04-14T11:05:31Z

← Older revision		Revision as of 11:05, 14 April 2011
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	The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.		The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.

	Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.		Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite(or slot<ref group="nb">The orbital planes of a constellation are usually divided in slots that should contain at least one operational satellite</ref>) or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

	The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (2D positioning plus time).		The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (2D positioning plus time).

Rui.Pereira at 14:21, 13 April 2011

2011-04-13T14:21:05Z

← Older revision		Revision as of 14:21, 13 April 2011
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	The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.		The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.

	Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite or by considering the availability of position, velocity and time (PVT) from the full ~~constelation~~<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.		Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite or by considering the availability of position, velocity and time (PVT) from the full constellation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

	The availability of a usable signal from a specific satellite...		The availability of a usable signal from a specific satellite is related with the correct behavior of the satellite. The availability of usable signal for a satellite will only guarantee that the pseudorange to the satellite will be known. For the availability of a PVT it is required that a lock can be made on the signal of at least 3 satellites (2D positioning plus time).

	When considering the availability of a PVT additional ~~contrains~~ can be added to define when the system is available. If a specific application requires that a PVT is only usable if the error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if ~~the~~ the system support integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.		When considering the availability of a PVT additional constraints can be added to define when the system is available. If a specific application requires that a PVT is only usable if the error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if the system support integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.

	~~Availabilty~~ can be influenced by several factors (see [[GNSS Performances]] for factors that influence the performance of GNSS) being the most important the ~~constelation~~ configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.		Availability can be influenced by several factors (see [[GNSS Performances]] for factors that influence the performance of GNSS) being the most important the constellation configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.

Rui.Pereira at 11:31, 13 April 2011

2011-04-13T11:31:30Z

← Older revision		Revision as of 11:31, 13 April 2011
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	Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite or by considering the availability of position, velocity and time (PVT) from the full constelation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.		Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite or by considering the availability of position, velocity and time (PVT) from the full constelation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

			The availability of a usable signal from a specific satellite...

	When considering the availability of a PVT additional contrains can be added to define when the system is available. If a specific application requires that a PVT is only usable if the error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if the the system support integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.		When considering the availability of a PVT additional contrains can be added to define when the system is available. If a specific application requires that a PVT is only usable if the error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if the the system support integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.

	Availabilty can be influenced by several factors (see [[GNSS ~~Performance~~]] for factors that influence the performance of GNSS) being the most important the constelation configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.		Availabilty can be influenced by several factors (see [[GNSS Performances]] for factors that influence the performance of GNSS) being the most important the constelation configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.

Rui.Pereira: Created page with "{{Article Infobox2 |Category=Fundamentals |Title={{PAGENAME}} |Authors=Rui Barradas Pereira |Level=Basic |YearOfPublication=2011 |Logo=GMV }} The availability of a navigation s..."

2011-04-13T11:29:38Z

Created page with "{{Article Infobox2 |Category=Fundamentals |Title={{PAGENAME}} |Authors=Rui Barradas Pereira |Level=Basic |YearOfPublication=2011 |Logo=GMV }} The availability of a navigation s..."

New page

{{Article Infobox2
|Category=Fundamentals
|Title={{PAGENAME}}
|Authors=Rui Barradas Pereira
|Level=Basic
|YearOfPublication=2011
|Logo=GMV
}}

The availability of a navigation system is the percentage of time that the services of the system are usable by the navigator. Availability is an indication of the ability of the system to provide usable service within the specified coverage area. Signal availability is the percentage of time that navigation signals transmitted from external sources are available for use. It is a function of both the physical characteristics of the environment and the technical capabilities of the transmitter facilities{{#tag:ref| This definition was adapted from the [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf 2008 US Federal Radionavigation Plan]<ref> [http://www.navcen.uscg.gov/pdf/2008_Federal_Radionavigation_Plan.pdf US Federal Radionavigation Plan], DOT-VNTSC-RITA-08-02/DoD-4650.5, 2008</ref>|group="nb"}}.

==Measuring Availability==

The availability is usually measured as percentage. Availability will then express the percentage of time that the system is usable by a receiver, user or application.

Particularizations of the availability concept can be made by considering the availability of a usable signal from a specific satellite or by considering the availability of position, velocity and time (PVT) from the full constelation<ref> [http://www.pnt.gov/public/docs/2008/spsps2008.pdf GPS Standard Positioning Service (SPS) Performance Standard], 4<sup>th</sup> Edition, September 2008.</ref>.

When considering the availability of a PVT additional contrains can be added to define when the system is available. If a specific application requires that a PVT is only usable if the error is below a certain threshold it can be said that the system is available only when the error meets that requirement. This approach will only make sense if the the system support integrity or if there is a reference system to measure errors. Otherwise the application doesn't have any way to determine whether the threshold is being violated or not.

Availabilty can be influenced by several factors (see [[GNSS Performance]] for factors that influence the performance of GNSS) being the most important the constelation configuration and its visibility at user location and the surrounding environment (buildings and other obstacles) that might mask part or all of the satellites in the sky.

==Notes==
<references group="nb"/>
==References==
<references/>

[[Category:Fundamentals]]