Satellite Realtime Navigation - Revision history

Filipe.Pelica: Included editor logo.

2014-09-18T16:28:52Z

Included editor logo.

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Filipe.Pelica: fixed broken link.

2014-09-11T10:41:41Z

fixed broken link.

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	[[File:ATV-JKepler OverSouthofFrancewithoutlasers.jpg\|right\|thumb\|400px\|ATV approaching ISS]]		[[File:ATV-JKepler OverSouthofFrancewithoutlasers.jpg\|right\|thumb\|400px\|ATV approaching ISS]]

	Currently kinematic Point Position solutions can achieve a navigation accuracy of 10 m and 0.1 m/s for GNSS receivers on Low Earth Orbit without further optimizations. This level of navigation accuracy is considered adequate for attitude and orbit control systems<ref>[http://www~~.weblab~~.dlr.de/~~rbrt~~/~~GpsNav~~/~~RTNav~~/~~RTNav.html~~ Real-Time Onboard Navigation], DLR</ref>. Meter level accuracy can be achieved using onboard Kalman filters and algorithms that take into account the dynamic model of the orbit.		Currently kinematic Point Position solutions can achieve a navigation accuracy of 10 m and 0.1 m/s for GNSS receivers on Low Earth Orbit without further optimizations. This level of navigation accuracy is considered adequate for attitude and orbit control systems<ref>[http://www.dlr.de/rb/desktopdefault.aspx/tabid-4736/10533_read-23359/ Real-Time Onboard Navigation], DLR</ref>. Meter level accuracy can be achieved using onboard Kalman filters and algorithms that take into account the dynamic model of the orbit.

	Experiments with the Proba-2 satellite show that 1-2 m positioning accuracy could be achieved using onboard advanced real-time navigation filters<ref name="Proba2">[http://www.esa.int/esaMI/Proba/SEMAZ65PVFG_0.html Laser tag caps Proba-2’s technology-testing year], ESA Portal, November 2010</ref>.		Experiments with the Proba-2 satellite show that 1-2 m positioning accuracy could be achieved using onboard advanced real-time navigation filters<ref name="Proba2">[http://www.esa.int/esaMI/Proba/SEMAZ65PVFG_0.html Laser tag caps Proba-2’s technology-testing year], ESA Portal, November 2010</ref>.

Carlos.Lopez at 10:57, 23 February 2012

2012-02-23T10:57:20Z

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Rui.Pereira at 17:17, 7 November 2011

2011-11-07T17:17:05Z

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	From the very beginning it was realized that GNSS systems could also be used for a wide range of scientific and other civil applications. New tracking methods that were not foreseen by the original developers of the systems, like carrier tracking, were proposed and, as soon as it was possible, successfully tested and used. One of the applications that was soon envisioned was the use of GPS for navigation of spacecraft. The first onboard receiver was installed and flown in a Landsat satellite even before the complete GPS constellation was deployed. Since that time, more receivers have been flown on satellites, at first as a demonstration of increasingly precise uses and now as the main operational means of navigation<ref>[http://www.esa.int/esapub/bulletin/bullet90/b90mur.htm Satellite Navigation Using GPS, T.J. Martín Mur & J.M. Dow, ESA Bulletin Nr. 90, May 1997]</ref>.		From the very beginning it was realized that GNSS systems could also be used for a wide range of scientific and other civil applications. New tracking methods that were not foreseen by the original developers of the systems, like carrier tracking, were proposed and, as soon as it was possible, successfully tested and used. One of the applications that was soon envisioned was the use of GPS for navigation of spacecraft. The first onboard receiver was installed and flown in a Landsat satellite even before the complete GPS constellation was deployed. Since that time, more receivers have been flown on satellites, at first as a demonstration of increasingly precise uses and now as the main operational means of navigation<ref>[http://www.esa.int/esapub/bulletin/bullet90/b90mur.htm Satellite Navigation Using GPS, T.J. Martín Mur & J.M. Dow, ESA Bulletin Nr. 90, May 1997]</ref>.

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	== Application Examples ==		== Application Examples ==

	*'''ATV - Automated Transfer Vehicle''' - Expendable, unmanned resupply spacecraft developed by the European Space Agency. GPS and a star tracker is used to automatically rendezvous with the International Space Station and at a distance of 249 m, the ATV computers use videometer and telegoniometer data for final approach and docking manoeuvres<ref>[~~[Wikipedia~~:~~Automated Transfer Vehicle\|Automated Transfer Vehicle in Wikipedia]~~]</ref>.		*'''ATV - Automated Transfer Vehicle''' - Expendable, unmanned resupply spacecraft developed by the European Space Agency<ref>[http://www.esa.int/SPECIALS/ATV/index.html Automated Transfer Vehicle], ESA Portal, March 2011</ref>. GPS and a star tracker is used to automatically rendezvous with the International Space Station and at a distance of 249 m, the ATV computers use videometer and telegoniometer data for final approach and docking manoeuvres<ref>[http://www.esa.int/SPECIALS/ATV/SEMWX432VBF_0.html ATV flight phases], ESA Portal, March 2011</ref>.
	*'''Proba-2''' - The Proba satellites are part of ESA’s In-orbit Technology Demonstration Programme, missions dedicated to the demonstration of innovative technologies<ref>[http://www.esa.int/esaMI/Proba/SEMJJ5ZVNUF_0.html About Proba-2], ESA Portal, November 2010</ref>. Proba-2 incorporates two experimental GPS receivers for demonstration of Satellite Realtime Navigation and Precise Orbit Determination<ref name="Proba2"/>.		*'''Proba-2''' - The Proba satellites are part of ESA’s In-orbit Technology Demonstration Programme, missions dedicated to the demonstration of innovative technologies<ref>[http://www.esa.int/esaMI/Proba/SEMJJ5ZVNUF_0.html About Proba-2], ESA Portal, November 2010</ref>. Proba-2 incorporates two experimental GPS receivers for demonstration of Satellite Realtime Navigation and Precise Orbit Determination<ref name="Proba2"/>.

Timo.Kouwenhoven: Text replace - "|Level=Medium" to "|Level=Intermediate"

2011-11-06T07:46:50Z

Text replace - "|Level=Medium" to "|Level=Intermediate"

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Timo.Kouwenhoven: Text replace - "|Authors=GMV." to "|Authors=GMV"

2011-11-01T13:50:23Z

Text replace - "|Authors=GMV." to "|Authors=GMV"

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Rui.Pereira at 15:15, 16 September 2011

2011-09-16T15:15:25Z

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	== Application Characterization ==		== Application Characterization ==

			[[File:ATV-JKepler OverSouthofFrancewithoutlasers.jpg\|right\|thumb\|400px\|ATV approaching ISS]]

	Currently kinematic Point Position solutions can achieve a navigation accuracy of 10 m and 0.1 m/s for GNSS receivers on Low Earth Orbit without further optimizations. This level of navigation accuracy is considered adequate for attitude and orbit control systems<ref>[http://www.weblab.dlr.de/rbrt/GpsNav/RTNav/RTNav.html Real-Time Onboard Navigation], DLR</ref>. Meter level accuracy can be achieved using onboard Kalman filters and algorithms that take into account the dynamic model of the orbit.		Currently kinematic Point Position solutions can achieve a navigation accuracy of 10 m and 0.1 m/s for GNSS receivers on Low Earth Orbit without further optimizations. This level of navigation accuracy is considered adequate for attitude and orbit control systems<ref>[http://www.weblab.dlr.de/rbrt/GpsNav/RTNav/RTNav.html Real-Time Onboard Navigation], DLR</ref>. Meter level accuracy can be achieved using onboard Kalman filters and algorithms that take into account the dynamic model of the orbit.

Rui.Pereira: moved Work in Progress:Satellite Realtime Navigation to Satellite Realtime Navigation over redirect

2011-09-02T16:43:53Z

moved Work in Progress:Satellite Realtime Navigation to Satellite Realtime Navigation over redirect

← Older revision	Revision as of 16:43, 2 September 2011
(No difference)

Rui.Pereira at 16:39, 2 September 2011

2011-09-02T16:39:56Z

← Older revision		Revision as of 16:39, 2 September 2011
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	== Application Architecture ==		== Application Architecture ==

	For Satellite Realtime Navigation it is not usually possible to rely on post-processing algorithms and ground based station networks. For Low Earth Orbit spacecrafts kinematic point position solutions present a similar accuracy ~~has~~ terrestrial applications<ref name="GNSS Apps">GNSS Applications and Methods - Chapter 13 - Space Applications, E. Gleen Lightsey, Artech House</ref>. This accuracy can be improved by using algorithms that incorporate a dynamic model of the spacecraft's orbit.		For Satellite Realtime Navigation it is not usually possible to rely on post-processing algorithms and ground based station networks. For Low Earth Orbit spacecrafts kinematic point position solutions present a similar accuracy as terrestrial applications<ref name="GNSS Apps">GNSS Applications and Methods - Chapter 13 - Space Applications, E. Gleen Lightsey, Artech House</ref>. This accuracy can be improved by using algorithms that incorporate a dynamic model of the spacecraft's orbit.

	GNSS receivers can be used also for attitude control and determination in a similar way as for [[Attitude Determination\|aviation attitude determination]]. For space applications typically 2 different setups can be used: ~~multiantenna~~ platforms ~~using~~ carrier-phase interferometry ~~or single~~ antenna ~~using~~ variation of received signal power~~<ref name="GNSS Apps"/>~~.		===Attitude Control===
			GNSS receivers can be used also for attitude control and determination in a similar way as for [[Attitude Determination\|aviation attitude determination]]. For space applications typically 2 different setups can be used<ref name="GNSS Apps"/>:
			* '''Multiantenna platforms''' - That use carrier-phase interferometry.
			* '''Single antenna''' - Using variation of received signal power.

	== Application Characterization ==		== Application Characterization ==

Rui.Pereira at 11:29, 1 September 2011

2011-09-01T11:29:11Z

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	Experiments with the Proba-2 satellite show that 1-2 m positioning accuracy could be achieved using onboard advanced real-time navigation filters<ref name="Proba2">[http://www.esa.int/esaMI/Proba/SEMAZ65PVFG_0.html Laser tag caps Proba-2’s technology-testing year], ESA Portal, November 2010</ref>.		Experiments with the Proba-2 satellite show that 1-2 m positioning accuracy could be achieved using onboard advanced real-time navigation filters<ref name="Proba2">[http://www.esa.int/esaMI/Proba/SEMAZ65PVFG_0.html Laser tag caps Proba-2’s technology-testing year], ESA Portal, November 2010</ref>.

	For attitude determination GNSS has been used mostly as a course sensor providing enough accuracy for some applications. But for applications that require high accuracy attitude determination other types of attitude sensors such as star trackers are preferred. Despite this the GNSS information is integrated with the other sensor data in the Attitude and Orbit control subsystem (AOCS) of the spacecraft and contributes to the attitude determination and attitude control of the spacecraft.		For attitude determination, GNSS has been used mostly as a course sensor providing enough accuracy for some applications. But for applications that require high accuracy attitude determination, other types of attitude sensors such as star trackers are preferred. Despite this the GNSS information, when available, is normally integrated with the other sensor data in the Attitude and Orbit control subsystem (AOCS) of the spacecraft and contributes to the attitude determination and attitude control of the spacecraft.

	== Application Examples ==		== Application Examples ==