Traffic collision avoidance system: Difference between revisions

Revision as of 05:01, 31 January 2025

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In spite of all this, most of the manufacturers do not take the above-mentioned opportunities to make simplified devices. As a result of market forces, many TAS systems operate just like TCAS I (with interference limiting, using TCAS I symbology, etc.), with some having even have better surveillance performance (in range and tracked aircraft) and specifications than TCAS I.

== Relationship to Automaticautomatic Dependentdependent Surveillancesurveillance – Broadcastbroadcast (ADS–B) ==

[[Automatic dependent surveillance – broadcast]] (ADS–B) messages are transmitted from aircraft equipped with suitable transponders, containing information such as identity, ___location, and velocity. The signals are broadcast on the 1090&nbsp;MHz radio frequency. ADS-B messages are also carried on a Universaluniversal Accessaccess Transceivertransceiver (UAT) in the 978&nbsp;MHz band.<ref name=ADS-B_UAT>[http://adsb.tc.faa.gov/WG5_Meetings/Meeting1/UAT-WP-1-09.pdf ADS-B System Description for the UAT] {{webarchive|url=https://web.archive.org/web/20110928062831/http://adsb.tc.faa.gov/WG5_Meetings/Meeting1/UAT-WP-1-09.pdf |date=2011-09-28 }}</ref>

TCAS equipment which is capable of processing ADS–B messages may use this information to enhance the performance of TCAS, using techniques known as "hybrid surveillance". As currently implemented, hybrid surveillance uses reception of ADS–B messages from an aircraft to reduce the rate at which the TCAS equipment interrogates that aircraft. This reduction in interrogations reduces the use of the 1030/1090&nbsp;MHz radio channel, and will over time extend the operationally useful life of TCAS technology. The ADS–B messages will also allow low cost (for aircraft) technology to provide real time traffic in the cockpit for small aircraft.<ref>{{cite web |url=http://www.duncanaviation.aero/straighttalk/adsb/tcas.php |title=TCAS 7.1 &#124; ADSB Straight Talk |publisher=Duncanaviation.aero |date=2012-03-01 |access-date=2013-09-22 |url-status=dead |archive-url=https://web.archive.org/web/20130516094932/http://www.duncanaviation.aero/straighttalk/adsb/tcas.php |archive-date=2013-05-16 }}</ref> Currently UAT based traffic uplinks are provided in Alaska and in regions of the East coast of the US.

Hybrid surveillance does not make use of ADS–B's aircraft flight information in the TCAS conflict detection algorithms; ADS–B is used only to identify aircraft that can safely be interrogated at a lower rate.