View source for Automatic Dependent Surveillance–Broadcast

{{Short description|Aircraft surveillance technology}}
{{Use dmy dates|date=September 2019}}
[[File:FAA NextGen ADS-B implementation.jpg|thumb|Conceptual of the ADS-B system, illustrating radio links between aircraft, ground station and satellite]]
'''Automatic Dependent Surveillance–Broadcast''' ('''ADS-B''') is an aviation surveillance technology and form of [[Airborne collision avoidance system#Aircraft collision avoidance|electronic conspicuity]] in which an [[aircraft]] determines its position via [[satellite navigation]] or other sensors and periodically broadcasts its position and other related data, enabling it to be tracked. The information can be received by [[air traffic control]] ground-based or satellite-based receivers as a replacement for [[secondary surveillance radar]] (SSR). Unlike SSR, ADS-B does not require an interrogation signal from the ground or from other aircraft to activate its transmissions. ADS-B can also receive [[Point-to-point (telecommunications)|point-to-point]] by other nearby equipped ADS-B equipped aircraft  to provide traffic [[situational awareness]] and support [[self-separation]].
ADS-B is "automatic" in that it requires no pilot or external input to trigger its transmissions. It is "dependent" in that it depends on data from the aircraft's navigation system to provide the transmitted data.<ref>{{cite web |url= https://www.airservicesaustralia.com/about-us/projects/ads-b/how-ads-b-works/ |title=How ADS-B works |date=28 November 2012 |publisher=[[Airservices Australia]] |access-date=26 July 2014}}</ref>
ADS-B is a key part of the [[International Civil Aviation Organization]]'s (ICAO) approved aviation surveillance technologies and is being progressively incorporated into national airspaces worldwide. For example, it is an element of the United States [[Next Generation Air Transportation System]] (NextGen), the [[Single European Sky ATM Research]] project (SESAR), and India's Aviation System Block Upgrade (ASBU).<ref name="Richards et al">{{cite journal |last=Richards |first=William R |author2=O'Brien, Kathleen |author3=Miller, Dean C|title=New Air Traffic Surveillance Technology |journal=Boeing Aero Quarterly |year=2010|volume=2 |url=http://www.boeing.com/commercial/aeromagazine/articles/qtr_02_10/pdfs/AERO_Q2-10_article02.pdf |access-date=7 April 2014}}</ref><ref name=upgarde>{{cite news |first= Guy|last= Gugliotta|title=An Air-Traffic Upgrade to Improve Travel by Plane | url = https://www.nytimes.com/2009/11/17/science/17air.html?pagewanted=all | work = [[The New York Times]] | date = 16 November 2009}}</ref><ref>{{cite web |url=http://www.aai.aero/misc/AIPS_2014_18.pdf |title=AUTOMATIC DEPENDENT SURVEILLANCE – BROADCAST (ADS-B) OUT BASED ATS SURVEILLANCE SERVICES |website=www.aai.aero |access-date=22 May 2022 |archive-url=https://web.archive.org/web/20160304051131/http://www.aai.aero/misc/AIPS_2014_18.pdf |archive-date=4 March 2016 |url-status=dead}}</ref> ADS-B equipment is mandatory for [[instrument flight rules]] (IFR) category aircraft in Australian airspace; the United States has required many aircraft (including all commercial passenger carriers and aircraft flying in areas that required a SSR transponder) to be so equipped since January 2020; and, the equipment has been mandatory for some aircraft in Europe since 2017.<ref>{{Citation | title = Automatic Dependent Surveillance—Broadcast (ADS–B) Out Performance Requirements To Support Air Traffic Control (ATC) Service | publisher = GPO | url = http://edocket.access.gpo.gov/2010/pdf/2010-12645.pdf |date=December 2010 | place = US}}</ref><ref>{{Cite web |url=http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2011:305:0035:0052:EN:PDF  |title=COMMISSION IMPLEMENTING REGULATION (EU) No 1207/2011 of 22 November 2011 laying down requirements for the performance and the interoperability of surveillance for the single European sky |format=PDF}}</ref><ref name="univweatheradsb">{{cite web|url=http://www.universalweather.com/blog/2013/09/ads-b-requirements-coming-into-effect/|publisher=Universal Weather|date=23 September 2013|title=ADS-B Requirements Coming into Effect|first=Jason|last=Davidson|access-date=30 September 2013|archive-date=28 September 2013|archive-url=https://web.archive.org/web/20130928152405/http://www.universalweather.com/blog/2013/09/ads-b-requirements-coming-into-effect/|url-status=dead}}</ref> Canada uses ADS-B for surveillance in remote regions not covered by traditional radar (areas around [[Hudson Bay]], the [[Labrador Sea]], [[Davis Strait]], [[Baffin Bay]] and southern [[Greenland]]) since January 15, 2009.<ref name=wings-magazine>{{cite web|url=https://www.wingsmagazine.com/breakthrough-technology-brings-air-traffic-surveillance-to-hudson-bay-2369/|title=Breakthrough technology brings air traffic surveillance to Hudson Bay|publisher=Wings Magazine|last=Fredericks|first=Carey|date=2009-01-26|access-date=2020-03-19}}</ref><ref name=navcan-mandate>{{cite web|url=https://www.navcanada.ca/EN/products-and-services/Aeronautical%20Studies/Aero-Study-Active-ADS-B%20Mandate-EN.pdf|title=Canadian ADS-B Out Performance Requirement Mandate|publisher=[[Nav Canada]]|date=August 2017|access-date=19 March 2020|archive-date=11 November 2020|archive-url=https://web.archive.org/web/20201111232248/https://www.navcanada.ca/EN/products-and-services/Aeronautical%20Studies/Aero-Study-Active-ADS-B%20Mandate-EN.pdf|url-status=dead}}</ref> Aircraft operators are encouraged to install ADS-B products that are interoperable with US and European standards, and Canadian air traffic controllers can provide better and more fuel-efficient flight routes when operators can be tracked via ADS-B.<ref>{{cite web |url= https://www.tc.gc.ca/en/services/aviation/reference-centre/advisory-circulars/ac-700-009.html|title=Advisory Circular (AC) No. 700-009|date=2019-02-28|access-date=2020-09-17}}</ref><ref name="ALPA">{{cite journal |last1=Freeze |first1=Christopher |title=Award-Winning Teamwork |journal=Air Line Pilot |date=December 2021 |pages=23–24}}</ref>
== Description ==
ADS-B is an airspace surveillance system which could eventually replace [[Secondary surveillance radar]] as the main surveillance method for controlling aircraft worldwide. In the United States ADS-B is an integral component of the NextGen national airspace strategy for upgrading and enhancing aviation infrastructure and operations.<ref name="ReferenceB" />
ADS-B enhances safety by making an aircraft visible, realtime, to [[air traffic control]] (ATC) and to other ADS-B In equipped aircraft with position and velocity data transmitted every second. Other uses of ADS-B data include: post-flight analysis, inexpensive flight tracking, planning, and dispatch.<ref name="ReferenceB" />
Within the United States, the ADS-B system has the ability to provide air traffic and government-generated graphical weather information at no cost through [[Traffic information service – broadcast|TIS-B]] and [[#Flight information services-broadcast (FIS-B)|FIS-B]] applications.<ref name="ReferenceB">{{Citation | url = http://www.freeflightsystems.com/prod_adsb.htm | title = Free flight systems | access-date = 19 April 2011 | archive-url = https://web.archive.org/web/20121117085647/http://www.freeflightsystems.com/prod_adsb.htm | archive-date = 17 November 2012 | url-status = dead | df = dmy-all }}</ref>
ADS-B consists of two distinct functions - "ADS-B Out" and "ADS-B In".  Each "ADS-B Out" aircraft periodically broadcasts information about itself, such as identification, current position, altitude and velocity through an onboard transmitter. ADS-B Out provides air traffic controllers with real-time aircraft position information that is, in most cases, more accurate than the information available with current radar-based systems. With more accurate information, ATC can manage and separate aircraft with improved precision and timing.<ref name = "freeflightsystems.com" />
"ADS-B In" is the reception and processing of transmitted ADS-B information (i.e. "ADS-B Out") by other aircraft.  In the US ADS-B In can also include other information for pilots transmitted from ATC ground stations such as FIS-B and TIS-B data.<ref name="freeflightsystems.com" /> These ground station data broadcasts  are typically made available only when an ADS-B Out broadcasting aircraft is nearby.<ref>{{Citation | url=http://www.aopa.org/News-and-Video/All-News/2014/April/02/Portable-ADS-B-seminar.aspx | title = What portable ADS-B receivers don't tell you| date = 4 February 2014}}</ref>
The ADS-B Out system relies on two [[avionics]] components aboard each aircraft: a [[Performance-based navigation#On-board performance monitoring and alerting|high-integrity]] [[satellite navigation]] source (i.e. [[GPS]] or other certified [[GNSS]] receiver) and a datalink (the ADS-B unit). There are several types of certified ADS-B data links, but the most common ones operate at 1090&nbsp;MHz, essentially a modified [[Air traffic control radar beacon system#Mode S|Mode S]] transponder, or at 978&nbsp;MHz.<ref name="ReferenceB" /> The FAA would like to see aircraft that operate exclusively below {{convert|18000|ft}} use the 978&nbsp;MHz link, as this will alleviate congestion of the 1090&nbsp;MHz frequency.<ref>{{Citation|contribution=Surveillance broadcast |type=general information |title=En route |publisher=FAA |place=US |url=http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/surveillance_broadcast/general_information/ |url-status=dead |archiveurl=https://web.archive.org/web/20110503210959/http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/surveillance_broadcast/general_information/ |archivedate=3 May 2011 }}</ref> To obtain ADS-B Out capability at 1090&nbsp;MHz, user-operators can install a new transponder or modify an existing transponder if the manufacturer offers an ADS-B upgrade (plus install a certified [[GNSS]] position source if one is not already present).<ref name="ReferenceB" />
==Benefits==
ADS-B provides many benefits to both pilots and air traffic control that improve both the safety and efficiency of flight.<ref>{{Citation|url=http://www.faa.gov/nextgen/ads-b/broadcastservices/ |title=ADS‐B |contribution=Broadcast services |publisher=FAA |place=US |url-status=dead |archiveurl=https://web.archive.org/web/20110429132832/http://www.faa.gov/nextgen/ads-b/broadcastservices/ |archivedate=29 April 2011 }}</ref><ref name="scardina">{{cite journal|last=Scardina |first=John |title=Overview of the FAA ADS-B Link Decision |publisher=Federal Aviation Administration |date=7 June 2002 |url=http://www.faa.gov/asd/ads-b/06-07-02_ADS-B-Overview.pdf |url-status=dead |archiveurl=https://web.archive.org/web/20070316010309/http://www.faa.gov/asd/ads-b/06-07-02_ADS-B-Overview.pdf |archivedate=16 March 2007 }}</ref>
When using an ''ADS-B In'' system, a pilot is able to view traffic information about surrounding aircraft if those aircraft are equipped with ADS-B Out. This information includes altitude, heading, speed, and distance to the aircraft. In addition to receiving position reports from ADS-B Out participants, in the US, TIS-B can provide position reports on non-ADS-B Out-equipped aircraft if suitable ground equipment and ground radar exist. ADS-R re-transmits ADS-B position reports between UAT and 1090&nbsp;MHz frequency bands.
Aircraft equipped with universal access transceiver (UAT) ''ADS-B In'' technology will be able to receive weather reports, and in the US, weather radar through flight information service-broadcast (FIS-B), which also transmits readable flight information such as [[temporary flight restrictions]] (TFRs) and [[NOTAM]]s.
ADS-B ground stations are significantly cheaper to install and operate compared to primary and secondary radar systems used by air traffic control for aircraft separation and control.
Unlike some alternative in-flight weather services currently being offered commercially, there will be no subscription fees to use ADS-B services or its various benefits in the US. The aircraft owner will pay for the equipment and installation, while the [[Federal Aviation Administration]] (FAA) will pay for administering and broadcasting all the services related to the technology.
===Safety===
;Situational awareness
ADS-B makes flying significantly safer for the aviation community by providing pilots with improved [[situational awareness]]. Pilots in an ADS-B In equipped cockpit will have the ability to see, on their in-cockpit flight display, other traffic operating in the airspace and have access to clear and detailed weather information. They will also be able to receive pertinent updates ranging from temporary flight restrictions to runway closings.
;Improved visibility
Even aircraft only equipped with ADS-B Out will benefit from air traffic controllers' ability to more accurately and reliably monitor their position. When using this system both pilots and controllers will see the same radar picture. Other fully equipped aircraft using the airspace around them will be able to more easily identify and avoid conflict with an aircraft equipped with ADS-B Out. With past systems such as the [[Traffic collision avoidance system|Traffic alert and Collision Avoidance System (TCAS)]] aircraft could only see other aircraft equipped with the same technology. With ADS-B, information is sent to aircraft using ADS-B In, which displays all aircraft in the area, provided those aircraft are equipped with ADS-B Out. ADS-B provides better surveillance in fringe areas of radar coverage. ADS-B does not have the siting limitations of radar. Its accuracy is consistent throughout the range.<ref>{{Citation | first = Randy | last = Babbitt | title = Speech | publisher = Aero Club of Metro Atlanta | date = 5 May 2011}} (FAA Administrator).</ref> In both forms of ADS-B (1090ES & 978&nbsp;MHz UAT), the position report is updated once per second. The 978&nbsp;MHz [[Universal Access Transceiver|UAT]] provides the information in a single, short-duration transmission. The 1090ES system transmits two different kinds of position reports (even/odd) randomly. To decode the position unambiguously, one position report of both kinds or a reference position nearby is needed.
ADS-B enables improved safety by providing:<ref name="miticat">{{Citation | contribution = Identification of ADS-B User Benefits to Incentivize GA Equipage | publisher = MIT International Center for Air Transportation | first1 = Fabrice | last1 = Kunzi | first2 = R John | last2 = Hansman | type = presentation | title = JUP Quarterly Meeting | date = 16–17 July 2009}}</ref>
* Radar-like [[Instrument Flight Regulations|IFR]] separation in non-radar airspace
* Increased [[Visual Flight Rules|VFR]] flight following coverage
* [[Air traffic control|ATC]] final approach and runway occupancy, reducing [[runway incursion]]s on the ground
* More accurate search and rescue response<ref name="miticat" />&nbsp;— although ADS-B can transmit "aircraft down" data, the FAA has stated that there is no intention to perform even a study of ADS-B's effectiveness in an "aircraft down" situation, simply based on the fact that ADS-B equipment has no requirement to be crashworthy, as compared to the current [[Flight recorder|"black box"]] recorder.{{Citation needed| date = February 2011}} ADS-B was demonstrated to the [[Civil Air Patrol]] (CAP) in March 2003 by [[Aircraft Owners and Pilots Association|AOPA]] via flight demonstrations for possible integration of the technology in CAP activities.<ref>{{Citation|title=What's new |contribution=AOPA demos ADS-B for Civil Air Patrol |url=http://www.aopa.org/whatsnew/newsitems/2003/03-4-14lx.html |date=4 March 2003 |url-status=dead |archiveurl=https://web.archive.org/web/20160722050012/http://www.aopa.org/whatsnew/newsitems/2003/03-4-14lx.html |archivedate=22 July 2016 }}</ref>
* Helps pilots to see and avoid other aircraft
* Cockpit final approach and runway occupancy
* Visual separation in VFR and MVFR conditions
* VFR-like separation in all weather conditions
* Real-time cockpit weather display
* Real-time cockpit airspace display
===Efficiency===
;Reduced environmental impact
ADS-B technology provides a more accurate report of an aircraft's position.<ref>{{Citation | publisher = FAA | place = US | title = Fact sheet | url = http://www.faa.gov/news/fact_sheets/news_story.cfm?newsid=7131}}</ref> This allows controllers to guide aircraft into and out of crowded airspace with smaller separation standards than it was previously possible to do safely. This reduces the amount of time aircraft must spend waiting for clearances, being vectored for spacing and holding. Estimates show that this is already having a beneficial impact by reducing pollution and fuel consumption.<ref>{{Citation | journal =Aviation Today | type = feature | title = Avionics driving efficiency gains | date = February 2009 | url = http://www.aviationtoday.com/av/issue/feature/Avionics-Driving-Efficiency-Gains_29234.html}}</ref>
;Traffic capacity improvement
ADS-B enables increased capacity and efficiency by supporting:
* Better ATC traffic flow management<ref name="miticat" />
* Merging and spacing<ref name="miticat" />
* [[Self-separation]] or station keeping<ref name="miticat" />
* Enhanced visual approaches;
* Closely spaced parallel approaches;
* Reduced spacing on final approach;
* Reduced aircraft separations;
* Enhanced operations in high altitude airspace for the incremental evolution of the "[[free flight (air traffic control)|free flight]]" concept;
* Surface operations in lower visibility conditions;
* Near visual meteorological conditions ([[Visual meteorological conditions|VMC]]) capacities throughout the airspace in most weather conditions;
* Improved air traffic control services in non-radar airspace;
* Trajectory-based operations provide a gently ascending and descending gradient with no step-downs or holding patterns needed. This will produce optimal trajectories with each aircraft becoming one node within a system-wide information management network connecting all equipped parties in the air and on the ground. With all parties equipped with NextGen equipment, benefits will include reduced gate-to-gate travel times, increased runway utilization capacity, and increased efficiency with carbon conservation.
* Use of ADS-B and CDTI may allow decreased approach spacing at certain airports to improve capacity during reduced-visibility operations when visual approach operations would normally be terminated (e.g.,&nbsp;ceilings less than MVA +500).{{Citation needed|date = December 2009}}
===Other applications===
The ADS-B data link supports a number of airborne and ground applications. Each application has its own operational concepts, algorithms, procedures, standards, and user training.{{Citation needed|date=January 2011}}
;Cockpit display of traffic information
A cockpit display of traffic information (CDTI) is a generic display that provides the flight crew with surveillance information about other aircraft, including their position. Traffic information for a CDTI may be obtained from one or multiple sources, including ADS-B, [[TCAS]], and TIS-B. Direct air-to-air transmission of ADS-B messages supports the display of proximate aircraft on a CDTI.{{Citation needed|date = January 2011}}
In addition to traffic based on ADS-B reports, a CDTI function might also display current weather conditions, terrain, airspace structure, obstructions, detailed airport maps, and other information relevant to the particular phase of flight.<ref name="do-242a" />
;Airborne collision avoidance
ADS-B is seen as a valuable technology to enhance [[airborne collision avoidance system]] (ACAS) operation. Incorporation of ADS-B can provide benefits such as:
* Decreasing the number of active interrogations required by ACAS, thus increasing effective range in high-density airspace.{{Citation needed |date=January 2011}}
* Reducing unnecessary alarm rate by incorporating the ADS-B state vector, aircraft intent, and other information.{{Citation needed | date = January 2011}}
* Use of the ACAS display as a CDTI, providing positive identification of traffic.{{Citation needed|date=January 2011}}
* Extending collision avoidance below 1,000 feet above ground level, and detecting runway incursions.{{Citation needed|date = January 2011}}
Eventually, the ACAS function may be provided based solely on ADS-B, without requiring active interrogations of other aircraft transponders.<ref name="do-242a" />
Other applications that may benefit from ADS-B include:
* Lighting control automation and operation
* Airport ground vehicle and aircraft rescue and firefighting vehicle operational needs
* Altitude height keeping performance measurements
* [[General aviation]] operations control<ref name="do-242a" />
* Conflict management
* ATS conformance monitoring
* [[Aircraft spotting]] where personal receivers can be used to produce a virtual radar picture
* A number of websites use [[crowd-sourcing|crowd-sourced]] distributed networks of ADS-B receivers to track air traffic.
==Security risk==
Aircraft with transponder only, or no transponder capability at all will not be shown. Pilots who become complacent or overconfident in this system are thus a safety problem, not only for themselves but for other transponder-only aircraft, and [[Glider (aircraft)|glider aircraft]] without ADS-B transponder.
Glider aircraft often use the [[FLARM]] system for collision avoidance with other glider aircraft, but this system is not compatible with ADS-B. Aircraft with ADS-B but without FLARM are thus a safety risk for gliders with FLARM but without ADS-B and vice versa. Some aircraft, like those used for towing gliders, have both FLARM and ADS-B transponders for this reason.
A security researcher claimed in 2012 that ADS-B has no defence against being interfered with via [[Spoofing attack|spoofed]] ADS-B messages because they were neither [[encrypted]] nor [[authenticated]].<ref>{{cite web|url=http://www.securityweek.com/air-traffic-control-systems-vulnerabilities-could-make-unfriendly-skies-black-hat|title=Air Traffic Control Systems Vulnerabilities Could Make for Unfriendly Skies [Black Hat]&nbsp;— SecurityWeek.Com|date=27 July 2012 }}</ref> The FAA responded to this criticism saying that they were aware of the issues and risks but were unable to disclose how they are mitigated as that is classified. A possible mitigation is [[multilateration]] to verify that the claimed position is close to the position from which the message was broadcast. Here the timing of received messages is compared to establish distances from the antenna to the plane.<ref>{{cite book|last1=Strohmeier|first1=Martin|last2=Lenders|first2=Vincent|last3=Martinovic|first3=Ivan|title=Proceedings of the 1st ACM Workshop on Cyber-Physical System Security |chapter=Lightweight Location Verification in Air Traffic Surveillance Networks |date=2015|pages=49–60 |doi=10.1145/2732198.2732202|isbn=9781450334488|s2cid=15259041|url=https://ora.ox.ac.uk/objects/uuid:eb56a190-5f73-4142-b739-1ddb39487b92 |chapter-url=https://www.cs.ox.ac.uk/files/7230/cpss_strohmeier.pdf}}</ref>
The lack of any authentication within the standard makes it mandatory to validate any received data by use of the primary radar. Because the content of ADS-B messages is [[Plaintext|not encrypted]], it may be read by anybody.<ref>{{cite web|url=http://www.lll.lu/~edward/edward/adsb/DecodingADSBposition.html|title=Decoding ADS-B position}}</ref>
[[File:Adscapture.png|thumb|An example of the reception of ADS-B signals on a [[software-defined radio]] dongle. These signals are not encrypted. Inexpensive hardware and free software can be used to display the speed, course, altitude, callsign and identification of an aircraft equipped with an ADS-B transponder.]]
==Theory of operation==
[[File:AERO Friedrichshafen 2018, Friedrichshafen (1X7A4803).jpg|thumb|A portable ADS-B receiver]]
The ADS-B system has three main components: 1) ground infrastructure, 2) airborne component, and 3) operating procedures.<ref>{{Citation | last1 = Mozdzanowska | first1 = Aleksandra | publisher = AIAA | contribution = Dynamics of Air Transportation System Transition and Implications for ADS-B Equipage | title = 7th Aviation Technology, Integration and Operations Conference (ATIO) | place = Belfast, Northern Ireland | date = 18–20 September 2007|display-authors=etal}}</ref>
* A transmitting subsystem that includes message generation and transmission functions at the source; e.g., aircraft.{{Citation needed | date =January 2011}}
* The transport protocol; e.g., [[VHF]] ([[VHF Data Link|VDL]] mode 2 or 4), 1090ES, or 978&nbsp;MHz UAT.{{Citation needed | date = January 2011}}
* A receiving subsystem that includes message reception and report assembly functions at the receiving destination; e.g., other aircraft, vehicle or ground system.{{Citation needed|date=January 2011}}
The source of the state vector and other transmitted information as well as user applications are not considered to be part of the ADS-B system.<ref name="do-242a">{{cite book | date= 25 June 2002 | title= Minimum Aviation System Performance Standards for Automatic Dependent Surveillance-Broadcast (ADS-B) | publisher=RTCA | id=[[DO-242A]]}}</ref>
===Physical layer===
Two link solutions are used as the physical layer for relaying ADS-B position reports: universal access transceiver,<ref name="do-282a">{{cite book | date= 29 July 2004 | title= Minimum Operational Performance Standards for Universal Access Transceiver (UAT) Automatic Dependent Surveillance – Broadcast | publisher=RTCA | id = [[DO-282A]]}}</ref> and 1090&nbsp;MHz [[Secondary surveillance radar#Extended squitter|extended squitter]].<ref name = "do-260a">{{cite book | date=10 April 2003 | title=Minimum Operational Performance Standards for 1090 MHz Extended Squitter Automatic Dependent Surveillance – Broadcast (ADS-B) and Traffic Information Services – Broadcast (TIS-B) | publisher= RTCA | id=[[DO-260A]]}}</ref><ref name="icao9871b">{{Cite book | title = ICAO Doc 9871, Technical Provisions for Mode S and Extended Squitter | isbn = 978-92-9249-042-3 | year = 2012 | author = ICAO | publisher = International Civil Aviation Organization | edition = 2 | url = http://www.icao.int/isbn/Lists/Publications/DispForm.aspx?ID=2052}}</ref>
====Universal Access Transceiver (UAT)====
A universal access transceiver is a [[data link]] intended to serve the majority of the [[general aviation]] community in the United States. The data link is approved in the [[Federal Aviation Administration]]'s "final rule" for use in all airspace except class A (above 18,000&nbsp;ft. [[Mean sea level|MSL]]). UAT is intended to support not only ADS-B, but also [[Automatic dependent surveillance-broadcast#Flight information services-broadcast (FIS-B)|flight information service – broadcast]] (FIS-B), [[Traffic Information Service – Broadcast|traffic information service – broadcast]] (TIS-B), and, if required in the future, supplementary ranging and positioning capabilities.<ref name = "ads-bforga.blogspot.com">{{Citation
| first = Fabrice | last = Kunzi
| url = http://ads-bforga.blogspot.com/2010/08/ads-b-avionics-architecture-1090es-and.html
| date = 30 August 2010 | work = ADS‐B forga
| title = ADS-B Avionics Architecture: 1090ES and UAT
| archiveurl = https://web.archive.org/web/20110708022006/http://ads-bforga.blogspot.com/2010/08/ads-b-avionics-architecture-1090es-and.html
| archivedate = 8 July 2011
}}</ref> Due to the set of standards required for this rule, it is seen as the most effective application for general aviation users. UAT will allow aircraft equipped with "out" broadcast capabilities to be seen by any other aircraft using ADS-B&nbsp;In technology as well as by FAA ground stations. Aircraft equipped with ADS-B In technology will be able to see detailed altitude and vector information from other ADS-B Out equipped aircraft as well as FIS-B and TIS-B broadcasts. The FIS-B broadcast will allow receiving aircraft to view weather and flight service information including [[Airmen's Meteorological Information|AIRMET]]s, [[Significant Meteorological Information|SIGMET]]s, [[Meteorological Aerodrome Report|METAR]]s, SPECI, national [[NEXRAD]], regional NEXRAD, D-NOTAMs, FDC-NOTAMs, [[Pilot report|PIREP]]s, special use airspace status, terminal area forecasts, amended [[terminal aerodrome forecast]]s (TAFs), and [[Winds aloft|winds and temperatures aloft forecast]]s.<ref name = "ReferenceA">{{Citation | publisher = ITT | title = FIS-B Product Summary | date = 25 January 2011}}</ref> These broadcasts serve to provide early adopters of the technology with benefits as an incentive for more pilots to use the technology before 2020. Aircraft receiving traffic information through the TIS-B service will see other aircraft in a manner that is similar to how all aircraft will be seen after they have been equipped by 2020. The availability of a non-subscription weather information service, FIS-B, provides general aviation users with a useful alternative to other monthly or annual fee-based services.
The UAT system is specifically designed for ADS-B operation. UAT is also the first link to be certified for "radar-like" ATC services in the United States. Since 2001 it has been providing {{convert|5|nmi|abbr=on}} en-route separation (the same as mosaic radar but not {{convert|3|nmi|abbr=on}} of single-site sensors) in Alaska. UAT is the only ADS-B link standard that is truly bidirectional: UAT users have access to ground-based aeronautical data (FIS-B) and can receive reports from proximate traffic (TIS-B) through a multilink gateway service that provides ADS-B reports for 1090ES-equipped aircraft and non-ADS-B equipped radar traffic. UAT-equipped aircraft can also observe each other directly with high accuracy and minimal latency. Viable ADS-B UAT networks are being installed as part of the United States' NextGen air traffic system.
====1090 MHz extended squitter====
In 2002 the [[Federal Aviation Administration]] (FAA) announced a dual-link decision using the 1090&nbsp;MHz [[Secondary surveillance radar#Extended squitter|extended squitter]] (1090&nbsp;ES) link for air carrier and private or commercial operators of high-performance aircraft, and universal access transceiver link for the typical general aviation user.<ref name="APA 27-02" /> In November 2012, the [[European Aviation Safety Agency]] confirmed that the European Union would also use 1090&nbsp;ES for interoperability.<ref>{{cite web|title=Approval requirements for Air&nbsp;— Ground Data Link and ADS&nbsp;— B in support of Interoperability requirements|url=http://www.easa.europa.eu/rulemaking/docs/crd/2012/CRD%202012-19.pdf|publisher=[[European Aviation Safety Agency]]|date=21 November 2012}}</ref> The format of extended [[squitter]] messages has been codified by the ICAO.<ref name="icao9871b" />
With 1090&nbsp;ES, the existing [[Air traffic control radar beacon system#Mode S|Mode S]] transponder ([[Technical Standard Order|TSO]] C-112 or a standalone 1090&nbsp;MHz [[transmitter]]) supports a message type known as the extended squitter message. It is a periodic message that provides position, velocity, time, and, in the future, intent. The basic ES does not offer intent since current flight management systems do not provide such data (called trajectory change points). To enable an aircraft to send an extended squitter message, the transponder is modified (TSO C-166A<ref>{{Citation | title = Regulatory & guidance library | contribution = TSO C‐166A | publisher = [[FAA]] | location = [[United States of America|US]] | url = http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgtso.nsf/0/3039f623d71c99f186257261006959e9/$FILE/TSO-C166A.pdf }}</ref>) and aircraft position and other status information is routed to the transponder. ATC ground stations and aircraft equipped with [[traffic collision avoidance system]] (TCAS) already have the necessary 1090&nbsp;MHz (Mode S) receivers to receive these signals, and would only require enhancements to accept and process the additional extended squitter information. As per the FAA ADS-B link decision, and the technical link standards, 1090&nbsp;ES does not support FIS-B service.<ref name="APA 27-02" />
===Relationship to surveillance radar===
Radar directly measures the range and bearing of an aircraft from a ground-based [[Antenna (radio)|antenna]]. The primary surveillance radar is usually a pulse radar. It continuously transmits high-power radio frequency (RF) pulses. Bearing is measured by the position of the rotating radar antenna when it receives the RF pulses that are reflected from the aircraft skin. The range is measured by measuring the time it takes for the RF energy to travel to and from the aircraft.
[[Radar configurations and types|Primary surveillance radar]] does not require any cooperation from the aircraft. It is robust in the sense that surveillance outage failure modes are limited to those associated with the ground radar system. [[Secondary surveillance radar]] depends on active replies from the aircraft. Its failure modes include the [[Transponder (aviation)|transponder]] aboard the aircraft. Typical ADS-B aircraft installations use the output of the navigation unit for navigation and for cooperative surveillance, introducing a common [[failure mode]] that must be accommodated in air traffic surveillance systems.<ref name="do-242a" />
{| class="wikitable"
|-
! Type !! Independent? !! Cooperative?
|-
| [[Radar configurations and types|Primary surveillance radar]] (PSR)
| Yes: surveillance data derived by radar
| No: does not depend on aircraft equipment
|-
| [[Secondary surveillance radar]] (SSR)
| No: surveillance data provided by aircraft transponder
| Yes: requires aircraft to have a working [[Air traffic control radar beacon system|ATCRBS]] transponder
|-
| Automatic dependent surveillance (ADS-B)
| No: surveillance data provided by aircraft
| Yes: requires aircraft to have a working ADS-B function
|-
| colspan="3"|Source: DO-242A<ref name="do-242a" />
|}
The radiated beam becomes wider as the distance between the antenna and the aircraft becomes greater, making the position information less accurate. Additionally, detecting changes in aircraft velocity requires several radar sweeps that are spaced several seconds apart. In contrast, a system using ADS-B creates and listens for periodic position and intent reports from aircraft. These reports are generated based on the aircraft's navigation system and distributed via one or more of the ADS-B data links. The accuracy of the data is no longer susceptible to the position of the aircraft or the length of time between radar sweeps.<ref name="APA 27-02">{{cite press release|title=FAA Announces Automatic Dependent Surveillance-Broadcast Architecture |publisher=FAA Office of Public Affairs |date=1 July 2002 |url=http://www.faa.gov/news/press_releases/news_story.cfm?newsId=5520&print=go |id=APA 27-02 |access-date=21 February 2011 |url-status=dead |archiveurl=https://web.archive.org/web/20121022201516/http://www.faa.gov/news/press_releases/news_story.cfm?newsId=5520&print=go |archivedate=22 October 2012 }}</ref> (However, the signal strength of the signal received from the aircraft at the ground station is still dependent on the range from the aircraft to the receiver, and interference, obstacles, or weather could degrade the integrity of the received signal enough to prevent the digital data from being decoded without errors. When the aircraft is farther away, the weaker received signal will tend to be more affected by the aforementioned adverse factors and is less likely to be received without errors. Error detection will allow errors to be recognized, so the system maintains full accuracy regardless of aircraft position when the signal can be received and decoded correctly. This advantage does not equate to a total indifference to the range of an aircraft from the ground station.)
Today's [[air traffic control]] (ATC) systems do not rely on coverage by a single radar. Instead, a multi-radar picture is presented via the ATC system's display to the [[Air traffic controller|controller]]. This improves the quality of the reported position of the aircraft, provides a measure of redundancy, and makes it possible to verify the output of the different radars against others. This verification can also use sensor data from other technologies, such as ADS-B and [[multilateration]].{{Citation needed|date=January 2011}}
===Relationship to ADS-A/ADS-C===
There are two commonly recognized types of ADS for aircraft applications:
* ADS-addressed (ADS-A), also known as ADS-Contract (ADS-C)
* ADS-broadcast (ADS-B)
ADS-A is based on a negotiated one-to-one peer relationship between an aircraft providing ADS information and a ground facility requiring receipt of ADS messages. For example, ADS-A reports are employed in the [[Future Air Navigation System]] (FANS) using the [[Aircraft Communications Addressing and Reporting System]] (ACARS) as the communication protocol. During a flight over areas without radar coverage, ''e.g.'', oceanic and polar, reports are periodically sent by an aircraft to the controlling air traffic region.<ref name="do-242a" />
===Traffic information service – broadcast (TIS–B)===
{{Main|Traffic information service – broadcast}}
Traffic information service – broadcast (TIS–B) supplements ADS-B's air-to-air services to provide complete situational awareness in the cockpit of all traffic known to the ATC system. TIS–B is an important service for an ADS-B link in airspace where not all aircraft are transmitting ADS-B information. The ground TIS–B station transmits surveillance target information on the ADS-B data link for unequipped targets or targets transmitting only on another ADS-B link.{{Citation needed|date=January 2011}}
TIS–B uplinks are derived from the best available ground surveillance sources:
* ground radars for primary and secondary targets{{Citation needed|date=January 2011}}
* multilateration systems for targets on the airport surface<ref>{{cite web |url= http://www.multilateration.com/applications/surface.html |title=Multilateration: Airport Surface |publisher=ERA a.s..|access-date=30 April 2013}}</ref>
* ADS-B systems for targets equipped with a different ADS-B link<ref name="scardina" />
===Multilink gateway service===
The multilink gateway service is a companion to TIS-B for achieving interoperability between different aircraft equipped with 1090ES or UAT by using ground-based relay stations. These aircraft cannot directly share air-to-air ADS-B data due to the different communication frequencies. In terminal areas, where both types of ADS-B link are in use, ADS-B/TIS-B ground stations use ground-to-air broadcasts to relay ADS-B reports received on one link to aircraft using the other link.<ref name="scardina" />
Although multilink "solves" the issue of heavy airliners working on one frequency vs. light aircraft, the dual frequency nature of the system has several potential issues:
* Since two aircraft on two different ADS-B frequencies must use a ground station to talk to each other, this introduces the ground station as a point of failure, although to be fair, the 1090 signal is dependent on secondary radar scans in any case (and thus cannot operate without a ground station).
* The time taken to traverse the full path from one aircraft, to the ground station, then to the second aircraft adds delay to the signal. This contrasts with two autonomous ADS-B transceivers on UAT, which have a shorter and shorter delay as they converge.
* Aircraft are frequently out of the range of ground-based radar due to altitude. Radar can be blocked by mountains, and typically is not useful for coverage near an airport unless that airport has radar. Thus, approach, departure, and especially taxi/ground-based operations are compromised (a major selling point of the system).
Because of the issues with multilink, many ADS-B manufacturers are designing ADS-B systems as dual-frequency capable.
=== Flight information services-broadcast (FIS-B) ===
FIS-B provides weather text, weather graphics, NOTAMs, [[Automatic terminal information service|ATIS]], and similar information. FIS-B is inherently different from ADS-B in that it requires sources of data external to the aircraft or broadcasting unit, and has different performance requirements such as periodicity of broadcast.<ref name="do-242a" />
In the United States, FIS-B services are provided over the UAT link in areas that have a ground surveillance infrastructure.<ref name = "scardina" /><ref>{{Cite web |title=ADS-B – ADS-B In Pilot Applications |author= |work=faa.gov |date= |access-date=30 April 2022 |url= https://www.faa.gov/air_traffic/technology/adsb/pilot/#fisb}}</ref>
Another potential aircraft-based broadcast capability is to transmit aircraft measurements of meteorological data.{{Citation needed | date = January 2011}}
==Implementations by country==
=== Australia ===
Australia has full continental ADS-B&nbsp;coverage above FL300 (30,000 feet).<ref name="flightglobal.com">{{Citation | url = http://www.flightglobal.com/articles/2009/12/23/336523/australia-in-world-first-for-nationwide-ads-b-coverage.html | title = Australia in world first for nationwide ADS-B coverage | first = Emma | last = Kelly | date = 23 December 2009 | newspaper = Flight International}}</ref> ADS-B equipment is mandatory for all aircraft flying at this altitude. To achieve this level of coverage [[Airservices Australia]] operates more than 70 ADS-B ground receiver sites. In Australia, the aviation regulator, the Civil Aviation Safety Authority, mandated a phased requirement for all Instrument Flight Rules (IFR) aircraft to be equipped with ADS-B Out by 2 February 2017. This applies to all Australian aircraft.
=== Canada ===
[[Nav Canada]] commissioned operational use of ADS-B in 2009 and is now using it to provide coverage of its northern airspace around [[Hudson Bay]], most of which currently has no radar coverage. The service was then extended to cover some oceanic areas off the east coast of Canada including the [[Labrador Sea]], [[Davis Strait]], [[Baffin Bay]], and part of the [[North Atlantic Tracks]] around southern [[Greenland]]. The service is expected to be later extended to cover the rest of the [[Canadian Arctic]], and to the rest of Canada.<ref name="tp-185">{{cite web | title=Aviation Safety Letter | url = http://www.tc.gc.ca/CivilAviation/publications/tp185/1-07/Pre-flight.htm#NAVCanada | publisher=Transport Canada, Civil Aviation |date=January 2007 | access-date = 1 May 2007}}</ref><ref name="NavCanada">{{cite press release|title=NAV Canada announces the acquisition of new surveillance technology to improve air traffic safety and customer efficiency |publisher=NAV Canada |date=12 February 2007 |url=http://www.navcanada.ca/NavCanada.asp?Language=en&Content=ContentDefinitionFiles\Newsroom\NewsReleases07\nr0212.xml |access-date=1 May 2007 |url-status=dead |archiveurl=https://web.archive.org/web/20070218200531/http://www.navcanada.ca/NavCanada.asp?Language=en&Content=ContentDefinitionFiles%5CNewsroom%5CNewsReleases%5C2007%5Cnr0212.xml |archivedate=18 February 2007 }}</ref><ref name=wings-magazine /><ref name=navcan-mandate />
In 2018, Nav Canada issued an aeronautical study<ref name="aerostudy">{{cite web | title=AERONAUTICAL STUDY: Canadian ADS-B Out Performance Requirements Mandate | url=https://www.navcanada.ca/EN/products-and-services/Study%20Recommendations/Study%20Final%20Report%20-%20ADS-B-EN.pdf | publisher=Nav Canada | date=August 2018 | access-date=5 March 2020}}</ref> proposing a mandate for [[#Satellite (space based) ADS-B Collection|Aireon-compatible]] ADS-B Out for all aircraft in Class A Airspace by 2021 and Class B Airspace by 2022, requiring a transponder capable of delivering antenna diversity performance.  In response to stakeholder feedback, Nav Canada later announced<ref name="changemandate">{{cite web | title=NOTICE OF CHANGE UPDATE Canadian ADS-B Out Performance Requirements Mandate | url=https://www.navcanada.ca/EN/products-and-services/Service%20Project%20Announcements/Notice%20of%20Change-ADS-B%20Mandate-EN.pdf | publisher=Nav Canada | access-date=5 March 2020}}</ref> that such equipment will not be mandated according to that timeline, but rather that suitably equipped aircraft would be handled on a priority basis.  The dates upon which equipment will be required for operation in Canadian airspace have been announced as August 10, 2023, for Class A Airspace, May 16, 2024, for Class B Airspace and Class C, D and E no sooner than 2026.<ref>{{Cite web |title=NAV CANADA ADS-B Performance Requirements |url=https://www.navcanada.ca/en/air-traffic/space-based-ads-b/ads-b-performance-requirements.aspx |access-date=2022-12-05 |website=www.navcanada.ca |language=en}}</ref>
In May 2021, the not-for-profit [http://cifib.ca Canadian In-Flight Information Broadcasting Association] announced<ref>{{Cite web|date=2021-05-28|title=CIFIB national network build|url=https://www.wingsmagazine.com/cifib-national-network-build/|access-date=2021-06-10|website=Wings Magazine|language=en-US}}</ref> its intention to build and operate a network broadcasting FIS-B (weather) and TIS-B (traffic) information on 978&nbsp;MHz. By spring 2022, five ground stations were operating in Ontario, with several more stations planned for Alberta and Saskatchewan. The Canadian network is fully compatible with the United States network. Aircraft can use the same ADS-B In receivers in both countries and the provided services operate seamlessly when crossing the border. CIFIB plans to have about 100 stations operating within a few years. Coverage in Canada will not be coast-to-coast but will focus on areas with higher traffic.
=== China ===
An American company ADS-B Technologies created one of the largest and most successful ADS-B systems in the world (an eight-station, 350+ aircraft network that spans more than 1,200&nbsp;[[Nautical mile|nmi]] across Central China). This was also the first UAT installation outside the United States. As of March 2009, more than 1.2&nbsp;million incident/failure-free flight hours have been flown with these ADS-B systems.{{Citation needed|date=October 2010}}
=== Iceland ===
As of 2010, [[Isavia]] is in the process of installing ADS-B across the North Atlantic Ocean.<ref>{{cite web|title=Annual Report 2010|url=http://www.isavia.is/files/english/annual_report_isavia-2010-en_web_.pdf|publisher=Isavia|access-date=2 February 2012|page=26|archive-url=https://web.archive.org/web/20130524073203/http://www.isavia.is/files/english/annual_report_isavia-2010-en_web_.pdf|archive-date=24 May 2013|url-status=dead}}</ref> The system is made up by 18 ADS-B&nbsp;receiver stations in [[Iceland]], [[Faroe Islands]], and [[Greenland]].<ref>{{cite web|title=ADS-B|url=https://www.isavia.is/en/corporate/air-navigation/adsb|publisher=Isavia |access-date= 21 September 2018}}</ref><ref>{{cite web|title=Isavia Signs Agreement to Deploy Space-Based ADS-B|url=https://www.isavia.is/en/corporate/news-and-media/news/isavia-signs-agreement-to-deploy-space-based-ads-b|publisher=Isavia |access-date= 21 September 2018}}</ref>
=== India ===
The Airports Authority of India (AAI), which manages the country's airspace, first commissioned German company Comsoft to install ADS-B ground stations at 14 airport sites nationwide in 2012. Comsoft finished installing seven new ADS-B ground stations under a second phase of deployment which India subsequently integrated into its ATC system in 2014, thus completing its ground network for automatic dependent surveillance-broadcast (ADS-B) tracking of aircraft.
In line with the International Civil Aviation Organization's aviation system block upgrade plan, AAI has said that its ADS-B network will provide redundant, satellite-based surveillance where radar coverage exists, fill gaps in surveillance where radar coverage is not possible due to high terrain or remote airspace and enable it to share ADS-B data with neighboring countries. The network covers the Indian subcontinent, plus parts of the Bay of Bengal and the Arabian Sea.<ref>{{Cite web|url=https://www.ainonline.com/aviation-news/air-transport/2014-06-13/india-completes-ads-b-ground-network-installation|title=India Completes ADS-B Ground Network Installation &#124; AIN|first=Bill|last=Carey|website=Aviation International News}}</ref><ref>{{ Cite web |url=http://www.icao.int/APAC/Meetings/2013_ADS_B_SITF12/SP03%20-%20IND%20ADS-B%20Implementation%20in%20India.pdf |author1=ICAO |author2=AAI |date=April 2013 |title=ADS-B Implementation in India}}</ref>
=== Sweden ===
LFV Group in Sweden has implemented a nationwide ADS-B&nbsp;network with 12 ground stations. Installation commenced during the spring of 2006, and the network was fully (technically) operational in 2007. An ADS-B–supported system is planned for operational usage in [[Kiruna]], Sweden, during spring 2009.{{Update after|2014|8|12}} Based on the VDL Mode&nbsp;4 standards, the network of ground stations can support services for ADS-B, TIS-B, FIS-B, GNS-B (DGNSS augmentation) and point-to-point communication, allowing aircraft equipped with VDL&nbsp;4-compliant transceivers to lower fuel consumption and reduce flight times.{{Citation needed|date=May 2007}}
=== United Arab Emirates ===
[[United Arab Emirates]] commissioned three operational redundant ADS-B ground stations in early 2009 and is now using ADS-B to provide enhanced coverage of its upper airspace in combination and integrated with conventional surveillance radars.<ref name="GCAA">{{cite press release|title=HH Sheikh Mohamed bin Zayed Opens Sheikh Zayed Centre|url=http://www.gcaa.ae/en/Pages/NewsDetails.aspx?NewsID=124|publisher=GCAA|location=UAE|date=November 2009|access-date=13 May 2010}}</ref><ref name="ATC-Network">{{cite press release|title=Further ADS-B Installations in Abu Dhabi through ComSoft|url=http://www.atc-network.com/News/29815/Further-ADS-B-Installations-in-Abu-Dhabi-through-COMSOFT|publisher=ComSoft|date=March 2009|access-date=13 May 2010|url-status=dead|archiveurl=https://web.archive.org/web/20090429083840/http://www.atc-network.com/News/29815/Further-ADS-B-Installations-in-Abu-Dhabi-through-COMSOFT|archivedate=29 April 2009}}</ref>
=== United States ===
To reduce congestion and cope with growing aircraft traffic, the [[Federal Aviation Administration]] has been developing the [[Next-Generation Air Transportation System]] (NextGen),<ref name = "freeflightsystems.com">{{Citation | title = Final Rule for ADS‐B Out | publisher = [[Federal Aviation Administration]] | date = 28 May 2010 | url = http://www.gpo.gov/fdsys/pkg/FR-2010-05-28/pdf/2010-12645.pdf}}</ref> including ADS-B. ADS-B equipment is built to meet one of two sets of industry standards, DO-260B and DO-282B.
Aircraft operating in the United States in the airspace classes listed below are required to carry equipment that produces an ADS-B Out broadcast. ADS-B Out broadcasts information about an aircraft through an onboard transmitter to a ground receiver, moving air traffic control from a radar-based system to a satellite-derived aircraft location system.<ref name = "freeflightsystems.com" />
There is no such mandate for ADS-B In, which receives data and provides it to in-cockpit displays.<ref>{{Citation | title = Flight planning | contribution = Next gen to guide you gate to gate | date = 2 November 2011 | publisher = AOPA | url = http://www.aopa.org/flightplanning/articles/2011/110228nextgen_to_guide_you_gate_to_gate.html | type = article}}</ref> The FAA airspace requirements intentionally exclude some airspace that is frequently used by general aviation.
{| class="wikitable"
|-
! [[airspace class (United States)|Airspace Class]] !! Altitude
|-
| A || All aircraft equipped
|-
| B || All aircraft equipped
|-
| C || All aircraft equipped
|-
| E || Where above both 10,000&nbsp;ft MSL and also above 2,500&nbsp;ft [[above ground level|AGL]]
|}
Operators can choose the 1090&nbsp;megahertz extended squitter broadcast link, or the universal access transceiver broadcast link. FAA did not adopt higher performance standards that would enable all of the initial ADS-B In applications, but these can optionally be adopted.<ref name="freeflightsystems.com" />
====Equipping aircraft====
Fleet: 250,000 GA aircraft that will need ADS-B by 2020 of which 165,000 aircraft are subject to ADS-B Out (Class I and Class II aircraft that generally fly below 18 000&nbsp;feet).<ref>{{Citation | first = Timothy 'Tim' | last = Shaver | contribution = FAA Avionics Maintenance Branch Manager | title = Dealers delight in new avionics at AEA'11 | editor-first = Mett | editor-last = Thurber | date = 29 April 2011 | publisher = Avionics}}</ref> FAA forecasts an increase in the GA&nbsp;fleet from 224,172 aircraft in 2010 to 270,920 aircraft in 2031, growing an average of 0.9% per year.<ref>{{Citation|publisher=FAA |title=Forecast |type=fact sheet |date=15 February 2011 |url=http://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=12440%20(FAA%20Forecast%20Fact%20Sheet%20-%20Fiscal%20Years%202011-31) |contribution=Fiscal Years 2011–31 |url-status=dead |archiveurl=https://web.archive.org/web/20130922122634/http://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=12440%20%28FAA%20Forecast%20Fact%20Sheet%20-%20Fiscal%20Years%202011-31%29 |archivedate=22 September 2013 }}</ref>
====Funding resources====
Recent (April 2011) US federal legislation via House Bill for FAA re-authorization permits<ref>{{USBill|112|HR|658}} section 221 (c)</ref> an "equipping fund" that includes a portion for some general aviation aircraft. The fund would provide financing at competitive rates backed by [[loan guarantee]]s.<ref>{{Citation | title = Aviation Week | date = 5 April 2011}}</ref> A [[public-private partnership]] has been formed as the NextGen Equipage Fund, LLC which is managed by NEXA Capital Partners, LLC.<ref>{{Citation|title=Nexa Capital Partners|url=http://www.nexacapital.com/index.php?content=About/PPP.php}}</ref>
====US implementation timetable====
{{Update|section|date=November 2014}}
The Federal Aviation Administration ADS-B implementation is broken into three segments each with a corresponding timeline. [[Ground segment]] implementation and deployment is expected to begin in 2009 and be completed by 2013 throughout the [[National Airspace System]] (NAS). Airborne equipment is user-driven and is expected to be completed both voluntarily based on perceived benefits and through regulatory actions (Rulemaking) by the FAA. The cost to equip with ADS-B Out capability is relatively small and would benefit the airspace with surveillance in areas not currently served by radar. The FAA intends to provide similar service within the NAS to what radar is currently providing (5&nbsp;[[nautical mile|nmi]] en route and 3&nbsp;nmi terminal radar standards) as a first step to implementation. However, ADS-B In capability is viewed as the most likely way to improve NAS throughput and enhance capacity.{{Citation needed | date = January 2011}}
In December 2008, Acting FAA Administrator [[Robert A. Sturgell]] gave the go-ahead for ADS-B to go live in southern Florida. The south Florida installation, which consists of 11 ground stations and supporting equipment, is the first commissioned in the United States, although developmental systems have been online in Alaska, Arizona, and along the East Coast since 2004. The completed system will consist of 794 ground station transceivers. The December 2008 action is in compliance with a late-term [[Executive order (United States)|executive order]] from [[George W. Bush]] which mandated accelerated approval of NextGen.<ref>{{Citation | title = FAA Officially Launches Radar's Replacement | journal = Flying Magazine | volume = 136 | issue = 3 | page = 18 |url=http://www.flyingmag.com/gear/avionics/faa-officially-launches-radars-replacement|date=9 March 2009}}</ref>
=====FAA segment 1 (2006–09)=====
ADS-B deployment and voluntary equipment, along with rule-making activities. Pockets of development will exploit equipment deployment in the areas that will provide proof of concept for integration to ATC automation systems deployed in the NAS.<ref name="adsbsched">{{Citation | archivedate = 28 October 2010 | archiveurl = https://web.archive.org/web/20101028012911/http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/surveillance_broadcast/schedule/ | url = http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/surveillance_broadcast/schedule/ | contribution = Schedule | title = Surveillance and Broadcast Services | place = US | publisher = [[FAA]]}}</ref> It is being developed at the FAA's [[William J. Hughes Technical Center]] near [[Egg Harbor City, New Jersey]].<ref name=upgarde />
=====FAA segment 2 (2010–14)=====
ADS-B ground stations will be deployed throughout the NAS, with an in-service decision due in the 2012–2013 time frame. Completed deployment will occur in 2013–14. Equipment rules have been finalized and the current standards are DO-282B for UAT and DO-260B for 1090ES:<ref name="adsbsched" />
* Airport situational awareness&nbsp;– a combination of detailed airport maps, airport multilateration systems, ADS-B systems and enhanced aircraft displays have the potential to improve Airport Surface Situational Awareness (ASSA) significantly, and Final Approach and Runway Occupancy Awareness (FAROA).<ref>DO-289 v2 E&F</ref>
* Oceanic In-trail&nbsp;– ADS-B may provide enhanced situational awareness and safety for Oceanic In-trail maneuvers as additional aircraft become equipped.{{Citation needed|date=May 2007}}
* Gulf of Mexico&nbsp;– in the Gulf of Mexico, where ATC radar coverage is incomplete, the FAA is locating ADS-B (1090&nbsp;MHz) receivers on oil rigs to relay information received from aircraft equipped with ADS-B extended squitters back to the Houston Center to expand and improve surveillance coverage.<ref name=upgarde />
* Terminal Airspace&nbsp;– ADS-B is currently in service for two terminal airspace areas, [[Louisville, Kentucky]], and [[Philadelphia]], Pennsylvania.
=====FAA segment 3 (2015–20)=====
ADS-B&nbsp;In equipment will be based on user-perceived benefit but is expected to be providing increased situational awareness and efficiency benefits within this segment. Those aircraft that choose to equip in advance of any mandate will see benefits associated with preferential routes and specific applications. Limited radar decommissioning will begin in the time frame with an ultimate goal of a 50% reduction in the secondary surveillance radar infrastructure.{{Citation needed|date=May 2007}}
On 27 May 2010, the FAA published its final rule mandating that by 2020 all aircraft owners will be required to have ADS-B Out capabilities when operating in any airspace that currently requires a transponder ([[Airspace class (United States)|airspace classes]] A, B, and C, and airspace class&nbsp;E at certain altitudes).<ref>{{cite web|url=https://www.federalregister.gov/documents/2010/05/28/2010-12645/automatic-dependent-surveillance-broadcast-ads-b-out-performance-requirements-to-support-air-traffic|date=27 May 2010 |title=Automatic Dependent Surveillance–Broadcast (ADS-B) Out Performance Requirements to Support air traffic control (ATC) Service |publisher=Federal Aviation Administration}}</ref>
On 14 June 2012, FreeFlight Systems and [[Chevron Corporation|Chevron]] received STC for the first rule-compliant ADS-B installation in GOMEX helicopters that was awarded by the FAA.
====Early adopters====
; Cargo Airline Association: Cargo carriers, notably [[United Parcel Service|UPS]].<ref name="upgarde" /> They operate at their hub airports largely at night. Much of the benefit to these carriers is envisioned through merging and spacing the arriving and departing traffic to a more manageable flow. More environmentally friendly and efficient [[area navigation]] (RNAV) descent profiles, combined with CDTI, may allow crews to eventually aid controllers with assisted visual acquisition of traffic and limited cockpit-based separation of aircraft. The benefits to the carrier are fuel and time efficiencies associated with idle descent and shorter traffic patterns than typical radar vectoring allows.{{Citation needed|date=May 2007}}
; [[Embry-Riddle Aeronautical University]]: ERAU has equipped its training aircraft at its two main campuses in Florida and Arizona with UAT ADS-B capability as a situational safety enhancement. The university has been doing this since May 2003, making it the first use in general aviation.<ref>{{cite web | title = Embry-Riddle Becomes First in General Aviation to Use Revolutionary ADS-B System | work = Erau | url = http://www.erau.edu/er/newsmedia/newsreleases/2003/track.html | date = 13 May 2003 | access-date = 27 July 2007 | url-status = dead | archiveurl = https://web.archive.org/web/20080112095730/http://www.erau.edu/er/newsmedia/newsreleases/2003/track.html | archivedate = 12 January 2008 | df = dmy-all}}</ref> With the addition of the [[Garmin G1000]] flight instrument system to their fleet in 2006, ERAU became the first fleet to combine a glass cockpit with ADS-B.<ref>{{cite web|title=Embry-Riddle Fleet First to Combine Glass Cockpit and ADS-B |url=http://www.skycontrol.net/reports/embry-riddle-fleet-first-to-combine-glass-cockpit-and-ads-b/ |archive-url=https://web.archive.org/web/20071216195124/http://www.skycontrol.net/reports/embry-riddle-fleet-first-to-combine-glass-cockpit-and-ads-b/ |url-status=dead |archive-date=16 December 2007 |date=3 February 2006 }}</ref>
; [[University of North Dakota]]: UND has received an FAA grant to test ADS-B and has begun to outfit their Piper Warrior fleet with an ADS-B package.<ref>{{cite web | title = UND Aerospace Researcher Awarded $302,459 Grant To Study Safety-Enhancing Technology | url = http://und.edu/news/archives/story.php?id=1962 | publisher = University of North Dakota | date = 17 November 2006 | access-date = 3 May 2007}}</ref>
==== Privacy ====
The FAA in America has come up with two systems to address privacy concerns<ref>{{Cite web |last=maxflight |date=2022-02-23 |title=692 ADSBexchange |url=http://www.airplanegeeks.com/2022/02/23/692-adsbexchange/ |access-date=2022-03-01 |website=Airplane Geeks Podcast |language=en-US}}</ref>
* Limiting Aircraft Data Displayed (LADD): Aircraft owners or designated representatives may request limiting aircraft data displayed (formally referred to as blocking) or unblocking flight tracking data. Flight tracking services that draw the data from FAA agree to block the information, though as noted elsewhere in this article, the data are unencrypted and may be available from non-FAA sources.
* Privacy ICAO Aircraft (PIA): Program to improve the privacy of eligible aircraft by enabling aircraft owners to request an alternate, temporary ICAO aircraft address, which will not be assigned to the owner in the Civil Aviation Registry (CAR). These are used in conjunction with a third party call sign:<ref>{{Cite web |title=ADS-B Privacy {{!}} Federal Aviation Administration |author= |work=faa.gov |date= |access-date=29 July 2024 |url= https://www.faa.gov/air_traffic/technology/equipadsb/privacy |quote=For the purposes of this program, a third-party call sign can be obtained from FlightPlan, ForeFlight, FlightAware, or ARINCDirect. }}</ref> DCM ([[Garmin]]/[[Fltplan.com]]),<ref>{{Cite web |title=DCM Call Signs Versus FAA Blocking |author= |work=flttrack.fltplan.com |date= |access-date=29 July 2024 |url= https://flttrack.fltplan.com/FltPlanInfo/FltPlan_DCM-Call-Signs-v-FAA-Blocking.htm}}</ref> FFL ([[ForeFlight]]),<ref>{{Cite web |title=ForeFlight - Call Signs |author= |work=ForeFlight |date= |access-date=29 July 2024 |url= https://www.foreflight.com/support/call-signs/}}</ref> FWR ([[FlightAware]]),<ref>{{Cite web |title=Privacy ICAO Address (PIA) - FlightAware |author= |work=FlightAware |date= |access-date=29 July 2024 |url= https://www.flightaware.com/commercial/pia/}}</ref> XAA ([[ARINCDirect]]/[[Collins Aerospace]]).<ref>{{Cite web |title=BizAv Privacy: How to Fly Incognito in the USA |author=AvBuyer |work=avbuyer.com |date= |access-date=29 July 2024 |url= https://www.avbuyer.com/articles/flight-department-management/bizav-privacy-how-to-fly-incognito-in-the-usa-113205}}</ref>
==System design considerations==
A concern for any ADS-B protocol is the capacity for carrying ADS-B messages from aircraft, as well as allowing the radio channel to continue to support any legacy services. For 1090&nbsp;ES, each ADS-B message is composed of a pair of [[data packet]]s. The greater the number of packets transmitted from one aircraft, the fewer aircraft that can participate in the system, due to the fixed and limited channel data [[Bandwidth (signal processing)|bandwidth]].
System capacity is defined by establishing a criterion for what the worst environment is likely to be, then making that a minimum requirement for system capacity. For 1090&nbsp;ES, both [[TCAS]] and [[ATCRBS]]/[[Secondary surveillance radar|MSSR]] are existing users of the channel. 1090&nbsp;ES ADS-B must not reduce the capacity of these existing systems.{{Citation needed|date=January 2011}}
The FAA national program office and other international aviation regulators are addressing concerns about ADS-B<ref name="Airsport">{{cite web | publisher = AirSport Corporation | url = http://www.airsport-corp.com/adsb2.htm | title = Will ADS-B increase safety and security for aviation? | date = August 2000 | url-status = dead | archiveurl = https://web.archive.org/web/20070209222607/http://www.airsport-corp.com/adsb2.htm | archivedate = 9 February 2007 | df = dmy-all}}</ref> non-secure nature of ADS-B transmissions. ADS-B messages can be used to know the location of an aircraft, and there is no means to guarantee that this information is not used inappropriately. Additionally, there are some concerns about the integrity of ADS-B transmissions. ADS-B messages can be produced, with simple, low-cost measures, which spoof the locations of multiple phantom aircraft to disrupt safe air travel. There is no foolproof means to guarantee integrity, but there are means to monitor this type of activity. This problem is however similar to the usage of ATCRBS/MSSR where false signals also are potentially dangerous (uncorrelated secondary tracks).{{Citation needed|date=January 2011}}
There are some concerns about ADS-B dependence on [[Global navigation satellite system|satellite navigation systems]] to generate state vector information,<ref>{{cite web |website=USCG Navigation Center |title=Vulnerability assessment of the transportation infrastructure relying on GPS |url=http://www.navcen.uscg.gov/ppt/Volpe%20Slides.ppt |format=[[PPT format|PPT]] |publisher=United States Coast Guard |date=5 October 2001 |access-date=16 September 2008}}</ref> although the risks can be mitigated by using redundant sources of state vector information; e.g., [[Global Positioning System|GPS]], [[GLONASS]], [[Galileo (satellite navigation)|Galileo]] or [[multilateration]].{{Citation needed|date=January 2011}}
There are some general aviation concerns that ADS-B removes anonymity of the VFR aircraft operations.<ref name = "Airsport" /> The ICAO 24-bit [[Transponder (aviation)|transponder]] code specifically assigned to each aircraft will allow monitoring of that aircraft when within the service volumes of the Mode-S/ADS-B system. Unlike the Mode A/C transponders, there is no code "1200"/"7000", which offers casual anonymity. Mode-S/ADS-B identifies the aircraft uniquely among all in the world, in a similar fashion as a [[MAC address]] for a network interface controller or the [[International Mobile Equipment Identity]] (IMEI) of a GSM phone.{{Citation needed| date =January 2011}} However, the FAA is allowing UAT-equipped aircraft to utilize a random self-assigned temporary ICAO address in conjunction with the use of beacon code 1200. 1090&nbsp;ES-equipped aircraft using ADS-B will not have this option.<ref>{{cite web|url=http://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1020472|title=FAA Advisory Circular 20-165A Airworthiness Approval of Automatic Dependent Surveillance&nbsp;— Broadcast (ADS-B) Out Systems|publisher=Federal Aviation Administration|date=7 November 2012}}</ref>
In order for the ADS-B system to function to the fullest extent, equipment for all aircraft in the airspace is required. This demands that transponder technology be scalable from the smallest aircraft to the largest aircraft to allow for 100% equipage for any given airspace. Current transponder technology is capable of equipping larger, traditional aircraft but a new type of transponder is required for equipping aircraft that are smaller and lighter or don't have electrical systems like the large traditionally transponder-equipped aircraft. The requirements for these smaller and lighter aircraft are mainly size, weight, and power (SWAP) and transponder technology must allow for equipage of these types of aircraft to enable saturation of ADS-B for total visibility in any given airspace.{{Citation needed|date=July 2016}}
On 7 June 2002 the FAA published a historical overview of its decision on the ADS-B link architecture for use in the [[National Airspace System]] (NAS).<ref name="scardina" />
==Technical and regulatory documents==
* ''Minimum Aviation System Performance Standards'' (MASPS)
* ''Minimum Operational Performance Standards'' (MOPS)
* [[DO-242A]]&nbsp;— ADS-B MASPS. Describes system-wide operational use of ADS-B.
==Satellite (space-based) ADS-B Collection==
A significant step forward for ADS-B is the reception by [[artificial satellite]]s of the ADS-B signal. It was tested for the first time in 2013 on ESA's [[PROBA-V]]<ref>{{Cite news|url=http://www.esa.int/Our_Activities/Space_Engineering_Technology/Proba_Missions/Proba-V_maps_world_air_traffic_from_space|title=Proba-V maps world air traffic from space|last=esa|work=European Space Agency|access-date=22 March 2018|language=en-GB}}</ref> and it is being deployed by companies like [[Spire Global]] using low-cost nanosatellites. [[Aireon]] is also working on space-based ADS-B with the [[Iridium satellite constellation|Iridium]] satellite network, a LEO (Low Earth Orbit) satellite network that was originally created to deliver phone and data service anywhere on the planet. By capturing ADS-B position data from aircraft flying below the satellite, the network will give the following capabilities:
* Air traffic control using surveillance-based separation standards will be possible over water, in areas that radar does not currently cover. Currently, air traffic control uses the larger procedural separation standard in oceanic and remote areas.
* As is currently possible in radar-covered areas, a position history will be available for lost aircraft, as in the case of [[Malaysia Airlines Flight 370]].
The system only receives ADS-B on aircraft broadcasting on the 1090&nbsp;MHz frequency. This limits the system generally to airliners and business aircraft, despite the fact that small aircraft are frequently off the radar due to mountains blocking the signal at low altitudes. The system could be compromised by smaller, private aircraft with exclusive belly-mounted ADS-B antennas, due to the aircraft hull blocking the signal.
The rationale for using the Iridium satellite network for this new capability was due to:
* The Iridium satellites fly very low and thus can receive the ADS-B out signals more reliably (transponders and ADS-B were designed for ground reception).
* Iridium satellites are replaced relatively frequently due to the increased air friction at their lower altitude, and thus lower lifespan. Thus the system would be deployed on iridium faster.
* Iridium provides worldwide coverage, including the poles.
In September 2016, [[Aireon]] and [[FlightAware]] announced a partnership<ref name="aireon_flightaware">{{cite web|url=http://aireon.com/2016/09/21/aireon-flightaware-globalbeacon/|title=Aireon and FlightAware Partner to Launch GlobalBeacon Airline Solution for ICAO Airline Flight Tracking Compliance|date=21 September 2016| access-date=21 September 2016}}</ref> to provide this global space-based ADS-B data to airlines for flight tracking of their fleets and, in response to [[Malaysia Airlines Flight 370]], for compliance with the ICAO Global Aeronautical Distress and Safety System (GADSS) requirement for airlines to track their fleets.<ref name="icao_gadss">{{cite web|url=http://www.icao.int/safety/globaltracking/Pages/GADSS-Update.aspx|title= Update on GADSS-Related Global Aircraft Tracking Initiatives |access-date=21 September 2016}}</ref> In December 2016, [[Flightradar24]] entered an agreement with Gomspace for space-based tracking in 2016.<ref>{{cite web |title=Satellite flight tracking – Flightradar24 Blog |url=https://www.flightradar24.com/blog/tag/satellite-flight-tracking/ |website=www.flightradar24.com|date=July 2016 }}</ref>
SpaceX subsequently placed 66 operational and 9 spare Iridium satellites in orbit over the course of 8 launches between 14 January 2017 and 11 January 2019. Another 6 spare satellites remain on the ground.
The ICAO describes space-based ADS-B as a [[technology]] equalizer, offering developing nations an [[Air traffic control radar beacon system|airspace surveillance]] capability.<!--ref name=AvWeek29oct2019-->
By 2020, 34 nations will deploy the system, including the 17 members of the [[Agency for Aerial Navigation Safety in Africa and Madagascar|Asecna]] in Africa, and the [[Corporación Centroamericana de Servicios de Navegación Aérea|Cocesna]] air navigation services agency in Central America.<!--ref name=AvWeek29oct2019-->
More frequent updates in the [[North Atlantic Tracks]] allowed reducing longitudinal [[Separation (aeronautics)|separation]] from {{cvt|40 to 14|nmi|km}} and lateral separations from {{cvt|23 to 19|nmi|km}}.<!--ref name=AvWeek29oct2019-->
The [[FAA]] plans an evaluation in the [[Caribbean]] airspace from March 2020 until 2021, to complement the unreliable [[Grand Turk Island]] radar which allows reducing separation from {{cvt|30 to 5|nmi|km}}.<ref name=AvWeek29oct2019>{{cite news |url= https://aviationweek.com/connected-aerospace/space-based-ads-b-makes-global-inroads |title= Space-Based ADS-B Makes Global Inroads |date= Oct 29, 2019 |author= Bill Carey |work= Aviation Week & Space Technology}}</ref>
==See also==
* [[Acronyms and abbreviations in avionics]]
* [[ASDE-X]]
* [[Automatic Identification System]], a conceptually similar system for marine vessels
* [[Advanced Train Control System]], a conceptually similar system for railroads
* [[Automatic Packet Reporting System]] (APRS), a conceptually similar GPS-based tracking system in the [[amateur radio]] service
* [[DO-212]], minimal operational performance standards for airborne automatic surveillance (ADS)
* [[Eurocat (air traffic control)]]
* [[FLARM]]
* [[Flight tracking]]
* [[Free flight (air traffic control)]]
* [[GPS aircraft tracking]]
* [[Portable collision avoidance system]]
* [[Traffic collision avoidance system]]
==References==
{{FAA.Gov}}
{{Reflist|30em}}
<!-- Dead note "ADS-B": {{cite web | title=ADS-B Home Page | url=http://adsb.tc.faa.gov/ADS-B.htm| publisher=Federal Aviation Administration| date= 21 April 2005}} -->
<!-- Dead note "mode_S": {{cite paper | author=Orlando, Dr. Vincent A| title=Automatic Dependent Surveillance Broadcast (ADS-B) Mode S Extended Squitter| publisher=FAA Working Group 3: 1090&nbsp;MHz ES Meeting 8 | date= 3–8 December 2001 | url=http://adsb.tc.faa.gov/WG3_Meetings/Meeting8/Squitter-Lon.pdf}} -->
==Further reading==
* {{cite book | first = Michael 'Mike' | last = Richards | series = G4WNC
| title=Virtual Radar Explained
| isbn=978-1-905086-60-3
| publisher=[[Radio Society of Great Britain]]
| year=2010}}
==External links==
* {{Citation | place = US | publisher = FAA | url = https://www.faa.gov/air_traffic/technology/adsb | title = Automatic Dependent Surveillance-Broadcast (ADS-B) | type = official website}} {{Citation | place = US | publisher = FAA | url =https://www.faa.gov/nextgen/library/media/getSmart_ADSB.pdf | title = ADS-B Broadcast Services | type = official website}}
* {{Citation|place=US |publisher=FAA |url=http://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=10173 |contribution=ADS-B In the Gulf of Mexico |title=Aviation News |url-status=dead |archiveurl=https://web.archive.org/web/20100607071703/http://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=10173 |archivedate=7 June 2010 }}
* {{Citation|url=http://www.aopa.org/whatsnew/newsitems/2007/070118ads-b.html |publisher=AOPA |title=News Archive |date=11 July 2007 |contribution=ADS‐B |url-status=dead |archiveurl=https://web.archive.org/web/20070817013307/http://www.aopa.org/whatsnew/newsitems/2007/070118ads-b.html |archivedate=17 August 2007 }}
* {{Citation |url=https://www.jetpilots.com/air21-lawsuit |publisher=JetPilots.com |title=FedEx Ordered ADS-B Security Whistleblower to Psychiatric Exam |date=31 May 2017 |contribution=ADS‐B |url-status=dead |archiveurl=https://web.archive.org/web/20181211034739/http://www.jetpilots.com/air21-lawsuit |archivedate=11 December 2018 |access-date=31 July 2019 }}
* {{Citation |url=https://medium.com/@bcastleton/nextgen-and-noise-pollution-the-faas-carte-blanche-to-send-planes-screaming-over-our-houses-dad4f3d4d29d |publisher=medium.com |title=Nextgen and Noise Pollution the FAAs Carte Blanche to Send Planes Streaming Over Our Houses |date=31 May 2017 |contribution=ADS‐B |url-status=dead |archiveurl=https://web.archive.org/web/20190818142440/https://medium.com/@bcastleton/nextgen-and-noise-pollution-the-faas-carte-blanche-to-send-planes-screaming-over-our-houses-dad4f3d4d29d |archivedate=18 August 2019 |access-date=18 August 2019 }}
* [https://cambridgepixel.com/products/tools-accessories/ads-b-monitor/ ADS-B Monitor] - a free tool to decode, display and log ADS-B messages
{{Authority control}}
{{DEFAULTSORT:Automatic Dependent Surveillance-Broadcast}}
[[Category:Avionics]]
[[Category:Air traffic control]]