GBAS Fundamentals - Revision history

Vicente.Navarro at 07:43, 23 April 2025

2025-04-23T07:43:08Z

← Older revision		Revision as of 07:43, 23 April 2025
Line 76:		Line 76:
	The GBAS Signal in Space is defined to be only the data broadcast from the ground to the aircraft subsystem. The Satellite Signals in Space are part of the basic GNSS satellite constellations.		The GBAS Signal in Space is defined to be only the data broadcast from the ground to the aircraft subsystem. The Satellite Signals in Space are part of the basic GNSS satellite constellations.

	The GBAS ground subsystem differential computed corrections (contained in Type 1 message), GBAS ground subsystem related data (contained in Type 2 message) and Final Approach Segments (FAS) (contained in Type 4 message) are transmitted to the aircraft users via VHF Data Broadcast (VDB) Signal. The GBAS Messages are encoded in this signal. The specification of GBAS message data format is contained in the [https://www.icao.int ICAO] SARPS Appendix B for the aspects related with the signal in space, as well as in the RTCA MOPS DO-253C for the minimum operational performance requirements applicable to the airborne GBAS receiver equipment.		The GBAS ground subsystem differential computed corrections (contained in Type 1 message), GBAS ground subsystem related data (contained in Type 2 message) and Final Approach Segments (FAS) (contained in Type 4 message) are transmitted to the aircraft users via VHF Data Broadcast (VDB) Signal. The GBAS Messages are encoded in this signal. The specification of GBAS message data format is contained in the [https://www.icao.int ICAO] Standards and Recommended Practices (SARPS) in Annex 10, Volume I, Appendix B for the aspects related with the signal in space, as well as in the RTCA MOPS DO-253C for the minimum operational performance requirements applicable to the airborne GBAS receiver equipment and EUROCAE ED-114A MOPS for Global Navigation Satellite Ground Based Augmentation System Ground Equipment to Support Category I Operations.

	The VDB radio frequencies used shall be selected from the radio frequencies in the band 108-117.975 MHz. The lowest assignable frequency shall be 108.025 MHz and the highest frequency assignable shall be 117.950 MHz. The separation between assignable frequencies (channel spacing) shall be 25 kHz.		The VDB radio frequencies used shall be selected from the radio frequencies in the band 108-117.975 MHz. The lowest assignable frequency shall be 108.025 MHz and the highest frequency assignable shall be 117.950 MHz. The separation between assignable frequencies (channel spacing) shall be 25 kHz.
Line 120:		Line 120:


	The GBAS performances are defined with respect to the level of service that the system is designed to provide. The main source for GBAS performances comes from civil aviation navigation safety requirements and they are different for each civil aviation operation, as specified in ICAO Standards and Recommended Practices, Annex 10 - Aeronautical Telecommunications, Volume I - Radio Navigational Aids, July 2023.		The GBAS performances are defined with respect to the level of service that the system is designed to provide. The main source for GBAS performances comes from civil aviation navigation safety requirements and they are different for each civil aviation operation, as specified in ICAO Standards and Recommended Practices (SARPs), Annex 10 - Aeronautical Telecommunications, Volume I - Radio Navigational Aids, July 2023.

	{\| class="wikitable"		{\| class="wikitable"

Vicente.Navarro at 07:37, 23 April 2025

2025-04-23T07:37:24Z

← Older revision		Revision as of 07:37, 23 April 2025
Line 47:		Line 47:
	The GBAS Ground Subsystem consists of:		The GBAS Ground Subsystem consists of:
	*2 to 4 GNSS Reference Receivers and their respective geographically separated antennas;		*2 to 4 GNSS Reference Receivers and their respective geographically separated antennas;
	* A VHF data broadcast (VDB) transmitter;		*A VHF data broadcast (VDB) transmitter;
	*A monitor system;		*A monitor system;
	*Approach Database (FAS data);		*Approach Database (FAS data);
Line 76:		Line 76:
	The GBAS Signal in Space is defined to be only the data broadcast from the ground to the aircraft subsystem. The Satellite Signals in Space are part of the basic GNSS satellite constellations.		The GBAS Signal in Space is defined to be only the data broadcast from the ground to the aircraft subsystem. The Satellite Signals in Space are part of the basic GNSS satellite constellations.

	The GBAS ground subsystem differential computed corrections (contained in Type 1 message), GBAS ground subsystem related data (contained in Type 2 message) and Final Approach Segments (FAS) (contained in Type 4 message) are transmitted to the aircraft users via VHF Data Broadcast (VDB) Signal. The GBAS Messages are encoded in this signal. The specification of GBAS message data format is contained in the [~~http~~://www.icao.~~org~~ ICAO] SARPS Appendix B for the aspects related with the signal in space, as well as in the RTCA MOPS DO-253C for the minimum operational performance requirements applicable to the airborne GBAS receiver equipment.		The GBAS ground subsystem differential computed corrections (contained in Type 1 message), GBAS ground subsystem related data (contained in Type 2 message) and Final Approach Segments (FAS) (contained in Type 4 message) are transmitted to the aircraft users via VHF Data Broadcast (VDB) Signal. The GBAS Messages are encoded in this signal. The specification of GBAS message data format is contained in the [https://www.icao.int ICAO] SARPS Appendix B for the aspects related with the signal in space, as well as in the RTCA MOPS DO-253C for the minimum operational performance requirements applicable to the airborne GBAS receiver equipment.

	The VDB radio frequencies used shall be selected from the radio frequencies in the band 108-117.975 MHz. The lowest assignable frequency shall be 108.025 MHz and the highest frequency assignable shall be 117.950 MHz. The separation between assignable frequencies (channel spacing) shall be 25 kHz.		The VDB radio frequencies used shall be selected from the radio frequencies in the band 108-117.975 MHz. The lowest assignable frequency shall be 108.025 MHz and the highest frequency assignable shall be 117.950 MHz. The separation between assignable frequencies (channel spacing) shall be 25 kHz.
Line 120:		Line 120:


	The GBAS performances are defined with respect to the level of service that the system is designed to provide. The main source for GBAS performances comes from civil aviation navigation safety requirements and they are different for each civil aviation operation~~. <ref name="ICAO_SARPS">[http://www.icao.org~~ ICAO] Standards and Recommended Practices, Annex 10, Volume 1 Radio ~~Navigation~~ Aids, July ~~2006</ref>~~		The GBAS performances are defined with respect to the level of service that the system is designed to provide. The main source for GBAS performances comes from civil aviation navigation safety requirements and they are different for each civil aviation operation, as specified in ICAO Standards and Recommended Practices, Annex 10 - Aeronautical Telecommunications, Volume I - Radio Navigational Aids, July 2023.

	{\| class="wikitable"		{\| class="wikitable"
Line 169:		Line 169:
	As indicated in the table above, the performance requirements are expressed in terms of four quantitative concepts, many of them to be interpreted as probabilistic figures:		As indicated in the table above, the performance requirements are expressed in terms of four quantitative concepts, many of them to be interpreted as probabilistic figures:
	* '''Accuracy''': is expressed in terms of Navigation System Error (NSE) as the difference between the real position of the aircraft and the position provided by the airborne equipment.		* '''Accuracy''': is expressed in terms of Navigation System Error (NSE) as the difference between the real position of the aircraft and the position provided by the airborne equipment.
	* '''Integrity''': is defined by [~~http~~://www.icao.~~org~~ ICAO] as a measure of the trust that can be placed in the correctness of the information supplied by the system.		* '''Integrity''': is defined by [https://www.icao.int ICAO] as a measure of the trust that can be placed in the correctness of the information supplied by the system.

	* '''Continuity''': is the probability that the specified system performance will be maintained for the duration of a phase of operation, presuming that the system was available at the beginning of that phase of operation and was predicted to operate throughout the operation. Lack of continuity means that the operation must be aborted (with the associated risk).		* '''Continuity''': is the probability that the specified system performance will be maintained for the duration of a phase of operation, presuming that the system was available at the beginning of that phase of operation and was predicted to operate throughout the operation. Lack of continuity means that the operation must be aborted (with the associated risk).

Claudia.Prajanu at 14:43, 24 July 2018

2018-07-24T14:43:19Z

← Older revision		Revision as of 14:43, 24 July 2018
Line 70:		Line 70:
	===GNSS Satellites Subsystem===		===GNSS Satellites Subsystem===

	The GBAS Satellites Subsystem is mainly the ~~[[GNSS systems description\|~~GNSS constellations]] declared operational for civil use. The minimum requirements of a GBAS system are limited for the use of GNSS satellites ranging sources, with additional ranging sources being supplied by SBAS as an option.		The GBAS Satellites Subsystem is mainly the GNSS constellations declared operational for civil use. The minimum requirements of a GBAS system are limited for the use of GNSS satellites ranging sources, with additional ranging sources being supplied by SBAS as an option.

	==GBAS Signal==		==GBAS Signal==

Filipe.Pelica: Included editor logo.

2014-09-18T17:07:34Z

Included editor logo.

← Older revision		Revision as of 17:07, 18 September 2014
Line 4:		Line 4:
	\|Level=Basic		\|Level=Basic
	\|YearOfPublication=2011		\|YearOfPublication=2011
			\|Logo=GMV
	\|Title={{PAGENAME}}		\|Title={{PAGENAME}}
	}}		}}

Carlos.Lopez at 11:32, 23 February 2012

2012-02-23T11:32:29Z

← Older revision		Revision as of 11:32, 23 February 2012
Line 1:		Line 1:
	{{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}}
	}}		}}

	A [[Ground-Based Augmentation System (GBAS)]] is a civil-aviation safety-critical system that supports local augmentation –at airport level– of the primary GNSS constellation(s) by providing enhanced levels of service that support all phases of approach, landing, departure and surface operations. While the main goal of GBAS is to provide [[Integrity\|integrity]] assurance, it also increases the [[Accuracy\|accuracy]] with position errors below 1 m (1 sigma).<ref name="GNSS Aug">[[Wikipedia:GNSS augmentation\|GNSS augmentation in Wikipedia]]</ref><ref name="Kaplan">E.D. Kaplan, C.J. Hegarty, ''Understanding GPS Principles and Applications”, 2nd Ed., Artch House, ISBN 1-58053-894-0, 2006.</ref>		A [[Ground-Based Augmentation System (GBAS)]] is a civil-aviation safety-critical system that supports local augmentation –at airport level– of the primary GNSS constellation(s) by providing enhanced levels of service that support all phases of approach, landing, departure and surface operations. While the main goal of GBAS is to provide [[Integrity\|integrity]] assurance, it also increases the [[Accuracy\|accuracy]] with position errors below 1 m (1 sigma).<ref name="GNSS Aug">[[Wikipedia:GNSS augmentation\|GNSS augmentation in Wikipedia]]</ref><ref name="Kaplan">E.D. Kaplan, C.J. Hegarty, ''Understanding GPS Principles and Applications”, 2nd Ed., Artch House, ISBN 1-58053-894-0, 2006.</ref>

Jose.Caro at 08:51, 13 July 2011

2011-07-13T08:51:35Z

← Older revision		Revision as of 08:51, 13 July 2011
Line 10:		Line 10:
	A [[Ground-Based Augmentation System (GBAS)]] is a civil-aviation safety-critical system that supports local augmentation –at airport level– of the primary GNSS constellation(s) by providing enhanced levels of service that support all phases of approach, landing, departure and surface operations. While the main goal of GBAS is to provide [[Integrity\|integrity]] assurance, it also increases the [[Accuracy\|accuracy]] with position errors below 1 m (1 sigma).<ref name="GNSS Aug">[[Wikipedia:GNSS augmentation\|GNSS augmentation in Wikipedia]]</ref><ref name="Kaplan">E.D. Kaplan, C.J. Hegarty, ''Understanding GPS Principles and Applications”, 2nd Ed., Artch House, ISBN 1-58053-894-0, 2006.</ref>		A [[Ground-Based Augmentation System (GBAS)]] is a civil-aviation safety-critical system that supports local augmentation –at airport level– of the primary GNSS constellation(s) by providing enhanced levels of service that support all phases of approach, landing, departure and surface operations. While the main goal of GBAS is to provide [[Integrity\|integrity]] assurance, it also increases the [[Accuracy\|accuracy]] with position errors below 1 m (1 sigma).<ref name="GNSS Aug">[[Wikipedia:GNSS augmentation\|GNSS augmentation in Wikipedia]]</ref><ref name="Kaplan">E.D. Kaplan, C.J. Hegarty, ''Understanding GPS Principles and Applications”, 2nd Ed., Artch House, ISBN 1-58053-894-0, 2006.</ref>

	The Ground Based Augmentation System (GBAS) is intended primarily to support		The Ground Based Augmentation System (GBAS) is intended primarily to support precision approach operations. It consists of a GBAS Ground Subsystem and a GBAS Aircraft Subsystem.
	precision approach operations. It consists of a GBAS Ground Subsystem and a
	GBAS Aircraft Subsystem.

	==Introduction: How a GBAS works==		==Introduction: How a GBAS works==
	The Ground Based Augmentation System (GBAS) will augment the Global Positioning System (GPS) to improve aircraft safety during airport approaches and landings. It is expected that the end-state configuration will pinpoint the aircraft's position to within one meter or less with a significant improvement in service flexibility and user operating costs. GBAS is comprised of ground equipment and avionics. The ground equipment includes 4 reference receivers, a GBAS ground facility, and a VHF data broadcast transmitter. This ground equipment is complemented by GBAS avionics installed on the aircraft.<ref>[ http://www.faa.gov/~~about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/laas/howitworks/ LAAS-How it works~~] ~~by FAA~~.~~</ref>~~		(The information in this section has been taken from [http://www.faa.gov/ FAA] homepage.)

	~~Signals from GPS satellites are received by the GBAS GPS Reference Receivers~~ (~~4 receivers for each~~ GBAS) at the ~~GBAS-equipped~~ airport. ~~The reference receivers calculate their~~ position ~~using GPS. The GPS Reference Receivers and GBAS Ground Facility work together~~ to ~~measure errors~~ in ~~GPS-provided position~~. ~~The~~ GBAS ~~Ground Facility produces a GBAS correction message based on the difference between actual and GPS-calculated position. Included in this message~~ is ~~suitable integrity parameters~~ and ~~approach path information~~. ~~This~~ GBAS ~~correction message is then sent to~~ a VHF data broadcast ~~(VDB)~~ transmitter.		A Ground Based Augmentation System (GBAS) augments the Global Positioning System (GPS) to improve aircraft safety during airport approaches and landings. It is expected that the end-state configuration will pinpoint the aircraft's position to within one meter or less with a significant improvement in service flexibility and user operating costs. GBAS is comprised of ground equipment and avionics. The ground equipment includes 4 reference receivers, a GBAS ground facility, and a VHF data broadcast transmitter. This ground equipment is complemented by GBAS avionics installed on the aircraft.<ref>[http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/laas/howitworks/ LAAS-How it works] by FAA.</ref>

	The VDB broadcasts the GBAS signal throughout the GBAS coverage area to avionics in GBAS-equipped aircraft. GBAS provides its service to a local area (approximately a 30 kilometer radius). The signal coverage is designed support the aircraft's transition from en route airspace into and throughout the terminal area airspace.		Signals from GPS satellites are received by the GBAS GPS Reference Receivers at the GBAS-equipped airport. The reference receivers calculate their position using GPS. The GPS Reference Receivers and GBAS Ground Facility work together to measure errors in GPS-provided position. The GBAS Ground Facility produces a GBAS correction message based on the difference between actual and GPS-calculated position which includes as well integrity parameters and approach path information. This GBAS correction message is then sent to a VHF data broadcast (VDB) transmitter.

			The VDB broadcasts the GBAS signal throughout the GBAS coverage area to avionics in GBAS-equipped aircraft. GBAS provides its service to a local area (approximately a 30 kilometer radius). The signal coverage is designed to support the aircraft's transition from en route airspace into and throughout the terminal area airspace.

	The GBAS equipment in the aircraft uses the corrections provided on position, velocity, and time to guide the aircraft safely to the runway. This signal provides ILS-look-alike guidance as low as 200 feet (60 m) above touchdown. GBAS will eventually support landings all the way to the runway surface.		The GBAS equipment in the aircraft uses the corrections provided on position, velocity, and time to guide the aircraft safely to the runway. This signal provides ILS-look-alike guidance as low as 200 feet (60 m) above touchdown. GBAS will eventually support landings all the way to the runway surface.

Irene.Hidalgo: /* Introduction: How a GBAS works */

2011-07-12T14:26:24Z

Introduction: How a GBAS works

← Older revision		Revision as of 14:26, 12 July 2011
Line 24:		Line 24:

	<gallery>		<gallery>
	Image:Laas_step1.jpg‎~~\|200px~~		Image:Laas_step1.jpg‎
	Image:Laas_step2.jpg‎~~\|200px~~		Image:Laas_step2.jpg‎
	Image:Laas_step3.jpg‎~~\|200px~~		Image:Laas_step3.jpg‎
	Image:Laas_step4.jpg‎~~\|200px~~		Image:Laas_step4.jpg‎
	</gallery>		</gallery>

Irene.Hidalgo: /* Introduction: How a GBAS works */

2011-07-12T14:26:05Z

Introduction: How a GBAS works

← Older revision		Revision as of 14:26, 12 July 2011
Line 24:		Line 24:

	<gallery>		<gallery>
	Image:Laas_step1.jpg‎		Image:Laas_step1.jpg‎\|200px
	Image:Laas_step2.jpg‎		Image:Laas_step2.jpg‎\|200px
	Image:Laas_step3.jpg‎		Image:Laas_step3.jpg‎\|200px
	Image:Laas_step4.jpg‎		Image:Laas_step4.jpg‎\|200px
	</gallery>		</gallery>

Irene.Hidalgo: /* Introduction: How a GBAS works */

2011-07-12T14:25:34Z

Introduction: How a GBAS works

← Older revision		Revision as of 14:25, 12 July 2011
Line 26:		Line 26:
	Image:Laas_step1.jpg‎		Image:Laas_step1.jpg‎
	Image:Laas_step2.jpg‎		Image:Laas_step2.jpg‎
	~~</gallery>~~

	~~<gallery>~~
	Image:Laas_step3.jpg‎		Image:Laas_step3.jpg‎
	Image:Laas_step4.jpg‎		Image:Laas_step4.jpg‎

Irene.Hidalgo: /* Introduction: How a GBAS works */

2011-07-12T14:25:21Z

Introduction: How a GBAS works

← Older revision		Revision as of 14:25, 12 July 2011
Line 26:		Line 26:
	Image:Laas_step1.jpg‎		Image:Laas_step1.jpg‎
	Image:Laas_step2.jpg‎		Image:Laas_step2.jpg‎
			</gallery>

			<gallery>
	Image:Laas_step3.jpg‎		Image:Laas_step3.jpg‎
	Image:Laas_step4.jpg‎		Image:Laas_step4.jpg‎
	</gallery>		</gallery>


	==GBAS Architecture==		==GBAS Architecture==