Since its inception, Automatic Dependent Surveillance–Broadcast (ADS-B) has evolved into an essential technology for managing air traffic. Combining an aircraft positioning source, aircraft avionics and ground infrastructure it creates a high-tech, accurate surveillance interface between aircraft and air traffic control. As a performance-based surveillance technology, ADS-B is more precise than radar and consists of two different services: aircraft broadcasting ADS-B Out to controllers and other aircraft, and pilots receiving ADS-B In in the cockpit.

The FAA pioneered ADS-B, which is now used throughout the U.S. aviation community to promote the safe and efficient use of the nation’s airspace. The FAA requires ADS-B in most controlled airspace and strongly encourages operators to install and use it even where it’s not required. More than 162,000 U.S. aircraft now have ADS-B avionics, according to FAA records. Some of the most exciting developments in commercial aviation within the last ten years have been technological improvements surrounding ADS-B transponder technologies. Here are a few of them.

TT31 Transponder

Trig’s TT31 stack transponder is a retrofit for the popular Bendix King legacy transponders. It will “plug and play” straight into an existing KT76A, KT76C and KT78A tray, reducing both installation time and cost. It provides pilots with Class 1 Mode S technology that is also 1090ES ADS-B Out capable, the latest international standard. The TT31 is compatible with many popular GPS sources including Garmin GNS and GTN navigators and the Trig TN70. This aids installation flexibility. A free FAA supplemental type certificate allows the TT31 to be installed as a compliant ADS-B Out solution in 650 aircraft types.

The TT31 has a clear, bright display and simple user interface. Features include a flight timer, stopwatch and altitude monitor, which can alert pilots of a deviation from their selected altitude. It features datalink support for the U.S. Traffic Information Service (TIS), up-linked from approach radars. TIS traffic can be displayed on a variety of portable and panel-mount displays; coverage includes most U.S. terminal areas.

GTX 345, GTX 335

Garmin’s GTX 345 and GTX 335 all-in-one ADS-B transponders include Extended Squitter (ES) ADS-B Out with options for built-in Wide Area Augmentation System (WAAS), as well as dual-link ADS-B In. The GTX 345/335 integrates on a wide variety of current and legacy Garmin displays, including select G1000 Integrated Flight Decks. Regardless of the existing avionics configuration, the GTX 345 unlocks more capabilities for pilots by displaying ADS-B traffic, subscription-free weather1, GPS position and back-up attitude information on the popular Garmin Pilot and ForeFlight mobile apps via Bluetooth and Connext wireless technology. The GTX 345/335 come in a convenient size and form factor, making it easy to replace the most popular transponders in the industry, like the Garmin GTX 327 and many others. Remote options are also available for compatibility with the GTN 650/750 series and G1000-equipped aircraft.

The GTX 345/335 incorporate the popular 1.65-inch (4.2-centimeter) panel-mount transponder and have a bright, sunlight-readable digital display including pressure altitude readout, dedicated buttons for numeric squawk code entry and a built-in timer. An option for an integrated WAAS/GPS position source provides aircraft owners and operators with an all-in-one solution that meets ADS-B Out requirements. Remote-mount options are also available for control and display within G1000 and GTN 650/750-equipped aircraft. The GTX 345 pairs with compatible displays to add subscription-free Flight Information Service-Broadcast (FIS-B) weather and ADS-B In traffic, incorporating exclusive features such as TargetTrend and TerminalTraffic.

tailBeaconX

Made by uAvionix, tailBeaconX is the world’s first transponder designed as a rear-position light replacement. The 1090 MHz Mode S ADS-B OUT transponder satisfies the requirements for all existing and future ADS-B regulations worldwide, especially those leveraging space-based ADS-B. It provides precise ADS-B data to satellite networks without the need for a variety of antennas and it also exceeds the performance of traditional panel installed transponders that use belly mount antennas. Mounting in place of an existing rear position light, the GPS, space-based and ground-based antennas are integrated in to the lens housing. No new holes or penetration of pressure vessels are required, which eases installation.

The tailBeaconX was developed with the needs of urban air mobility (UAM) in mind. Electric vertical take-off and landing (eVTOL) aircraft, powered by batteries and alternative fuels, require radically different solutions than those that exist today. The device weighs only 90 grams (3 ounces), takes no critical volume from an internal avionics bay, incorporates its own antennas, and draws only 3 watts of power.

LYNX

L3Harris Technologies’ LYNX ADS-B In/Out family of ADS-B transponders offers an array of new-generation features and capabilities. Unlike other ADS-B solutions, the Lynx has a full-color split touchscreen where pilots can see ADS-B traffic on the left and then weather, terrain and active traffic on the right side. With a swipe of the finger, pilots can easily scroll through a variety of screens, including weather and traffic from the FAA (FIS-B & TIS-B) in real-time.

FIS-B weather data includes METARs, AIRMETs, SIGMETs, and NEXRAD, which is displayed on a moving map showing position. Additionally, if pilots are equipped with a Stormscope WX-500, they can also display lightning with the Lynx unit. A 978/1090 MHz dual-band receiver provides traffic and weather. Patented Tail provides flight ID, aircraft type and the ground speed of other ADS-B traffic.

MX12B

Sagetech Avionics’ next-gen MX12B miniature transponder is the first micro Mode 5 IFF transponder certified to the full DoD AIMS Mk XIIB specification. It packages Mode 5, Mode S, and complete ADS-B In and Out capability in a device that is at least 93% smaller and six times lighter than traditional certified military Mode 5 IFF transponders. It is certified to Defense Department AIMS 17-1000 MARK XIIB specification and is fully compliant for crewed and uncrewed aircraft.

BendixKing

BendixKing’s KT 74 is an ADS-B Out transponder that is a slide-in replacement for existing KT 76 and KT 78 transponders. The KT 74 broadcasts on 1090 MHz and can be expanded to also receive ADS-B In using a universal access transceiver (UAT), providing weather and traffic information. Since it is a slide-in replacement for an existing transponder, no time is spent cutting panels or mounting racks, replacing mounting trays or installing a new wiring harness. It has a black powder-coated aluminum bezel and an easy-to-read light blue LCD display.

The Most Precise Tracking Possible

With all these diverse ADS-B transponder benefits, one of ADS-B’s most important benefits is the ability to track air traffic in real time, according to the FAA.

“It improves safety and efficiency in the air and on the airport surface,” the FAA said. “ADS-B provides air traffic control (ATC) with updated aircraft position information almost every second, while radars can take anywhere from five to 12 seconds to update. These functions also increase general aviation pilot awareness and safety.”

ADS-B standards are developed through a Radio Technical Commission for Aeronautics (RTCA) committee, a consensus-based standards development organization consisting of government (including the FAA, Department of Defense, and others), industry, professional associations, and academia. To comply with the ADS-B Out operating rules, ADS-B Out equipment must meet the performance requirements specified in FAA Technical Standard Orders that are based on those RTCA standards. It must also broadcast a specified set of data, with specified regulatory requirements for position and velocity accuracy, integrity, and design assurance.