Space Applications - Revision history

Gema.Cueto: /* Antena */

2021-05-21T11:35:54Z

Antena

← Older revision		Revision as of 11:35, 21 May 2021
Line 25:		Line 25:
	=== Antena ===		=== Antena ===

	Usually terrestrial receivers antennas have a hemispherical reception pattern since the GNSS signals will come from the sky and ground based vehicle and even ~~aircrafts~~ rarely bank more than 45 degrees<ref>GNSS Applications and Methods - Chapter 13 - Space Applications, E. Gleen Lightsey, Artech House</ref>. For space-borne vehicles the reception needs to be omni directional with the exception of particular cases where the spacecraft's attitude is somehow stabilized in relation to the GNSS constellation. To achieve omnidirectional reception the most common approach is the use of multiple antennas although other solutions such as modifying the antenna gain pattern can also be used. While space doesn't generally present external sources of signal reflection causing multipath, multipath can be self-induced by the reflection on the spacecraft surface. Also in docking maneuvers or formation flying there might be problems due to multipath due to the reflection of the GNSS signal on the other spacecrafts surfaces. This might have an impact on antenna placement and mitigation techniques could be required.		Usually terrestrial receivers antennas have a hemispherical reception pattern since the GNSS signals will come from the sky and ground based vehicle and even aircraft rarely bank more than 45 degrees<ref>GNSS Applications and Methods - Chapter 13 - Space Applications, E. Gleen Lightsey, Artech House</ref>. For space-borne vehicles the reception needs to be omni directional with the exception of particular cases where the spacecraft's attitude is somehow stabilized in relation to the GNSS constellation. To achieve omnidirectional reception the most common approach is the use of multiple antennas although other solutions such as modifying the antenna gain pattern can also be used. While space doesn't generally present external sources of signal reflection causing multipath, multipath can be self-induced by the reflection on the spacecraft surface. Also in docking maneuvers or formation flying there might be problems due to multipath due to the reflection of the GNSS signal on the other spacecrafts surfaces. This might have an impact on antenna placement and mitigation techniques could be required.

	=== Footprint ===		=== Footprint ===

Claudia.Prajanu at 15:17, 7 September 2018

2018-09-07T15:17:27Z

← Older revision		Revision as of 15:17, 7 September 2018
Line 5:		Line 5:
	\|YearOfPublication=2011		\|YearOfPublication=2011
	\|Logo=GMV		\|Logo=GMV
	~~\|Title={{PAGENAME}}~~
	}}		}}
	GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.		GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.
Line 52:		Line 51:
	[[File:Proba-3.jpg\|right\|thumb\|200px\|Satellite Formation Flying]]		[[File:Proba-3.jpg\|right\|thumb\|200px\|Satellite Formation Flying]]

	All space missions are difficult. Docking a pair of spacecraft is tough but flying multiple satellites together in formation is the real cutting edge. In formation flying separate expensive pieces of hardware, each one zipping through space at several kilometres per second, may have to manoeuvre to within metres of each other to achieve their goals<ref name="FormSimul">[http://~~www~~.esa.int/~~esaCP/SEMQ71HONDG_index_0.html~~ Simulating the formation-flying future of space], ESA Portal, September 2010</ref>.		All space missions are difficult. Docking a pair of spacecraft is tough but flying multiple satellites together in formation is the real cutting edge. In formation flying separate expensive pieces of hardware, each one zipping through space at several kilometres per second, may have to manoeuvre to within metres of each other to achieve their goals<ref name="FormSimul">[http://m.esa.int/ESA Simulating the formation-flying future of space], ESA Portal, September 2010</ref>.

	The relative positions of the satellites must be maintained precisely as they close in: lose control of one part of the formation, even momentarily, and the satellites risk destruction. And orbital dynamics dictate the satellites’ orbits will tend to cross as they circle Earth, another worrying factor for their controllers<ref name="FormSimul"/>.		The relative positions of the satellites must be maintained precisely as they close in: lose control of one part of the formation, even momentarily, and the satellites risk destruction. And orbital dynamics dictate the satellites’ orbits will tend to cross as they circle Earth, another worrying factor for their controllers<ref name="FormSimul"/>.

Filipe.Pelica: fixed broken link.

2014-10-16T13:35:43Z

fixed broken link.

← Older revision		Revision as of 13:35, 16 October 2014
Line 9:		Line 9:
	GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.		GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.

	The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[~~https~~://~~directory~~.~~eoportal.org/web/eoportal/satellite-missions/l~~/~~landsat-4-5~~ Landsat-4 and -5], eoPortal</ref>.		The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[http://archive.today/V9jCi Landsat-4 and -5], eoPortal</ref>.

	== Operational Constraints of Space-borne Receivers ==		== Operational Constraints of Space-borne Receivers ==

Filipe.Pelica: Included editor logo.

2014-09-18T17:03:35Z

Included editor logo.

← Older revision		Revision as of 17:03, 18 September 2014
Line 4:		Line 4:
	\|Level=Intermediate		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011
			\|Logo=GMV
	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	}}		}}

Filipe.Pelica: fixed broken link.

2014-09-08T17:48:48Z

fixed broken link.

← Older revision		Revision as of 17:48, 8 September 2014
Line 8:		Line 8:
	GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.		GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.

	The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[https://directory.eoportal.org/web/eoportal/satellite-missions/l/landsat-4-5], eoPortal </ref>.		The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[https://directory.eoportal.org/web/eoportal/satellite-missions/l/landsat-4-5 Landsat-4 and -5], eoPortal</ref>.

	== Operational Constraints of Space-borne Receivers ==		== Operational Constraints of Space-borne Receivers ==

Filipe.Pelica: fixed broken link.

2014-09-08T17:47:44Z

fixed broken link.

← Older revision		Revision as of 17:47, 8 September 2014
Line 8:		Line 8:
	GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.		GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.

	The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[~~http~~://~~www~~.eoportal.org/~~directory~~/~~pres_Landsat4and5.html Landsat~~-4 ~~and~~ -5], eoPortal </ref>.		The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[https://directory.eoportal.org/web/eoportal/satellite-missions/l/landsat-4-5], eoPortal </ref>.

	== Operational Constraints of Space-borne Receivers ==		== Operational Constraints of Space-borne Receivers ==

Filipe.Pelica: footnotes harmonizing

2014-01-10T16:24:47Z

footnotes harmonizing

← Older revision		Revision as of 16:24, 10 January 2014
Line 21:		Line 21:

	=== Orbit ===		=== Orbit ===
	Orbit altitude and geometry are also a constraining factor for space-borne receivers. GPS satellites orbit the earth at an altitude of roughly 20 200 km and the GNSS signal is transmitted by directional antennas pointed to earth and taking into account the earth diameter. For Low Earth Orbit<ref group="nb" >between 160 and 2,000 km altitude</ref> spacecrafts the signal reception conditions are roughly the same as in terrestrial applications. When progressing in Medium Earth Orbit until near the altitude of the GPS satellites signal acquisition becomes increasingly more difficult since it is more likely that the spacecraft will fall outside the coverage cone of the GPS satellite signal and might require to track weaker signals from the sidelobes of the satellite or to track satellites on the opposite side of the earth not being obstructed by it. For Medium Earth Orbit above the GPS satellites orbit, High Earth Orbit or High Elliptical Orbits the problem becomes even more harsh since only the weaker signals from the sidelobes and the signal from satellites in the opposite side of earth are available.		Orbit altitude and geometry are also a constraining factor for space-borne receivers. GPS satellites orbit the earth at an altitude of roughly 20 200 km and the GNSS signal is transmitted by directional antennas pointed to earth and taking into account the earth diameter. For Low Earth Orbit<ref group="footnotes" >between 160 and 2,000 km altitude</ref> spacecrafts the signal reception conditions are roughly the same as in terrestrial applications. When progressing in Medium Earth Orbit until near the altitude of the GPS satellites signal acquisition becomes increasingly more difficult since it is more likely that the spacecraft will fall outside the coverage cone of the GPS satellite signal and might require to track weaker signals from the sidelobes of the satellite or to track satellites on the opposite side of the earth not being obstructed by it. For Medium Earth Orbit above the GPS satellites orbit, High Earth Orbit or High Elliptical Orbits the problem becomes even more harsh since only the weaker signals from the sidelobes and the signal from satellites in the opposite side of earth are available.

	=== Antena ===		=== Antena ===
Line 58:		Line 58:

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

	==References==		==References==

Teresa.Ferreira: /* Operational Contraints of Space-borne Receivers */

2012-09-10T10:44:35Z

Operational Contraints of Space-borne Receivers

← Older revision		Revision as of 10:44, 10 September 2012
Line 10:		Line 10:
	The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[http://www.eoportal.org/directory/pres_Landsat4and5.html Landsat-4 and -5], eoPortal </ref>.		The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16<sup>th</sup> 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation<ref>[http://www.eoportal.org/directory/pres_Landsat4and5.html Landsat-4 and -5], eoPortal </ref>.

	== Operational ~~Contraints~~ of Space-borne Receivers ==		== Operational Constraints of Space-borne Receivers ==

	The space environment presents differences from the terrestrial environment that don't allow us to take the assumption that a receiver working flawlessly on the ground will work properly in space.		The space environment presents differences from the terrestrial environment that don't allow us to take the assumption that a receiver working flawlessly on the ground will work properly in space.
Line 29:		Line 29:
	=== Footprint ===		=== Footprint ===

	As any spaceborne device, spaceborne devices have very strict constraints in what regards size, shape, weight, power consumption and overall robustness to the space environment. Space GNSS receiver should be as small and light as possible and should have a reduced power consumption. Shape constraints might be different from mission to mission and the receiver should be robust enough to survive the vibration load on liftoff and eventually re-entry. Space receivers should be able to withstand ionizing radiations between 9 to 100 or more kilorads.		As any spaceborne device, spaceborne devices have very strict constraints in what regards size, shape, weight, power consumption and overall robustness to the space environment. Space GNSS receiver should be as small and light as possible and should have a reduced power consumption. Shape constraints might be different from mission to mission and the receiver should be robust enough to survive the vibration load on liftoff and eventually re-entry. Space receivers should be able to withstand ionizing radiations between 9 to 100 or more kilorads.

	== Precise Orbit Determination ==		== Precise Orbit Determination ==

Carlos.Lopez at 10:57, 23 February 2012

2012-02-23T10:57:33Z

← Older revision		Revision as of 10:57, 23 February 2012
Line 1:		Line 1:
	{{Article Infobox2		{{Article Infobox2
	\|Category=Applications		\|Category=Applications
	\|~~Title={{PAGENAME}}~~		\|Editors=GMV
	~~\|Authors~~=GMV
	\|Level=Intermediate		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011
	\|~~Logo~~=~~GMV~~		\|Title={{PAGENAME}}
	}}		}}

	GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.		GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations<ref>[http://www.esa.int/esaNA/SEM6OTLVGJE_index_0.html Innovative satellite navigation receivers for space applications], ESA Portal, February 16th 2006</ref>.

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

2011-11-06T07:46:51Z

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

← Older revision		Revision as of 07:46, 6 November 2011
Line 3:		Line 3:
	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	\|Authors=GMV		\|Authors=GMV
	\|Level=~~Medium~~		\|Level=Intermediate
	\|YearOfPublication=2011		\|YearOfPublication=2011
	\|Logo=GMV		\|Logo=GMV