Garmin is a leader in Automatic Dependent Surveillance-Broadcast.
By Marty Rollinger
ATP. Challenger 600 & 604,
Falcon 2000 EASy and McDonnell Douglas F/A-18
With a little over 2 months until the US Automatic Dependent Surveillance-Broadcast (ADS-B) Out mandate goes into effect, most aircraft have completed installation. This benefits all operators of aircraft equipped with ADS-B In traffic displays.
Users of ADS-B In technology gain increased situational awareness (SA) when all aircraft nearby are ADS-B Out equipped. In this article, the 5th in the series on ADS-B In traffic awareness, the numerous benefits of ADS-B In traffic will be recapped while offerings from Garmin are highlighted.
For the past 3 decades, the company has advanced steadily the design and functionality of modern avionics and has played a significant role in the development of ADS-B technology.
ADS-B describes a system of electronic transmitting and receiving. Automatic transmissions occur with no pilot input required. The precise position and velocity information transmitted are dependent on GPS. Surveillance means the system provides 3D position and identification of aircraft and vehicles. ADS-B Out broadcasts continuously.
The transmissions contain a hefty amount of information that is extraordinarily useful to air traffic controllers and airborne recipients. The information transmitted includes exact position, velocity, altitude, flight identification, wake turbulence category, squawk code, system health data and, in some cases, selected altitude.
The “In” part of ADS-B entails being equipped with a receiver that can listen to all “Out” transmissions, and a method to display the traffic info to the flightcrew. The most remarkable data transmitted is velocity; not just speed, but track and ground speed. This track information significantly increases crew SA and decreases cockpit workload.
In the US, there are 2 variants of ADS-B – 1090ES (for Extended Squitter) and UAT (for Universal Access Transceiver). Garmin offers a wide range of products that incorporate both options. The international ADS-B Out mandates, both currently in effect and those soon-to-be-enforced, unanimously call for the use of 1090ES via a Mode S transponder.
Similarly, all US operations flying above 18,000 ft will require 1090ES ADS-B Out broadcast. For these reasons, most turbine business aviation operators choose the 1090ES version of ADS-B. The 1090ES ADS-B integrates well with the Traffic Collision Avoidance System (TCAS), since the TCAS antennas are already able to receive 1090 MHz signals.
A traffic computer receives both ADS-B Out data and separate TCAS data from nearby aircraft, which the computer correlates and integrates to depict on the traffic display, allowing for exceptional SA.
ADS-B vs ADS-C
ADS-C (Contract) is a subsystem of the Future Air Navigation System (FANS) 1/A. Naming may suggest that ADS-C is a later version, or superior sibling, to ADS-B. However, this is not the case. The systems use separate transmission mediums and have different purposes. ADS-C is an electronic contract and it’s valid only during the time an aircraft is in FANS 1/A airspace.
The contracts are offered by ATC through satellite communications or VHF radio, and adhered to by the transiting aircraft. ADS-C is used to replace periodic voice position reports in remote and oceanic regions where no ground-based surveillance systems are available. ADS-C consist of 3 types: periodic contract, event contract, and demand contract.
Each type specifies the conditions when an ADS-C report will be initiated, and what data will be contained in the report. Aircraft can also send unsolicited ADS-C emergency reports to a controller that has established an ADS contract with the aircraft.
Garmin is a leader in ADS-B
In As a major supplier to the business aviation community, Garmin currently provides its very capable integrated avionics platforms to turbine aircraft manufactured by Bell, Bombardier, Cessna, Cirrus, Daher, Embraer, Honda, Leonardo and Piper. Garmin is in the unique position of building a range of ADS-B In products from portable options to fully installed and certified traffic systems.
The company’s traffic display design is consistent and standardized across its range of products. Inexpensive portable Garmin data link (GDL) ADS-B In systems, like the GDL 50/52 models, receive multiple sources of information such as 1090ES and UAT ADS-B In, Wide Area Augmentation System (WAAS) GPS, and optional SiriusXM Weather.
These receivers then send the traffic and weather data to portable displays (eg, iPads) held or mounted in the cockpit. In addition, Garmin’s Pilot app, used to view traffic and weather, is highly intuitive, and updates are published frequently that come with new features. Installed GDL transceivers, like the GDL 88, allow traffic information to be displayed on compatible certified flight displays or on select portable and mobile devices via Bluetooth.
The GDL 88 is the 1st dual-link solution for certified aircraft that not only provides a path to ADS-B Out compliance, but also brings subscription-free weather and advanced traffic display to the cockpit. The GDL 88 is approved for installation in hundreds of popular fixed wing and rotary-wing aircraft models.
Garmin traffic systems
Garmin traffic systems (GTS) include GTS 800 series, GTS 850/855 TCAS I, and GTS 8000 TCAS II. Each GTS includes a processor that connects to all the required antennae, displays, controls, and aircraft interfaces. The same antennae are used to receive transponder replies and ADS-B broadcasts from other aircraft. GTS correlate data from multiple sources to create a single, fused traffic picture for the flightcrew.
What is correlation? Say there is a target ahead that has both ADS-B Out and a transponder. Your aircraft will receive the target’s ADS-B Out broadcast transmissions each second, which include accurate position, target track and flight identification. Your TCAS equipment will also receive information from this target every time the target aircraft answers an interrogation.
These 2 sets of data received from separate sources could represent the same aircraft or 2 different aircraft. So, correlation is the software function that intelligently compares received data from multiple sources to create a single, fused traffic picture for the flightcrew. Lastly, there’s GTS 8000, which delivers an integrated solution with the accuracy and early warning benefits of ADS-B In along with TCAS II resolution advisory functionality.
Traffic display functionality
Garmin traffic displays support 2 modes: airborne situational awareness (AIRB) and surface situational awareness (SURF). Directional track symbols will show a motion vector of selectable length. Motion vectors are presented as absolute or through Garmin’s TargetTrend relative motion technology. Rather than providing a fixed “snapshot” of the traffic situation, TargetTrend gives a faster, more intuitive way to judge direction and closure rate of intruding traffic targets relative to own ship position.
Traffic symbols are interactive for additional information. A pilot selects a traffic symbol by either direct touch or by placing a cursor over the traffic symbol. This selection opens a new window displaying precise ground speed, track and distance info. Buried deep in the system are more comprehensive details like wake turbulence category, emergency squawk and selected altitude.
Traffic displays can be decluttered by selecting above, below, normal, or unrestricted altitude filters to remove unwanted traffic. Unlike TCAS, ADS-B In provides awareness of traffic aircraft that are on the ground. With Garmin’s TerminalTraffic, pilots see a comprehensive picture of ADS-B-equipped aircraft and ground vehicles in the airport environment.
Service vehicles and taxiing aircraft are easily distinguished from aircraft in-flight with distinct colors and symbols, all presented on a simple, easy-to-understand SafeTaxi diagram with reference to runways, taxiways and hangar locations. Garmin presents ADS-B In traffic on the primary flight display (PFD) and in the soon-to-be-certified head-up display (HUD).
Because ADS-B In traffic is precisely located, symbols representing aircraft ahead can be accurately placed in 3 dimensions into the synthetic vision scene that is presented on the PFD. Brian Ast, Garmin senior systems and human factors engineer, says the traffic symbols appear larger as they are getting closer, and smaller when they are further away.
The symbol will change to a yellow circle when a traffic alert becomes active, and it will become a red square when a TCAS resolution advisory is declared. The monochrome HUD symbol changes shape and size only.
ADS-B In is the best in traffic awareness
Compared to TCAS alone, Garmin ADS-B In is the clear winner for traffic awareness. ADS-B In systems are not currently mandated but will become as indispensable as airborne weather radar. Just as airborne weather radars warn pilots of potentially hazardous weather, ADS-B In traffic displays warn flightcrews of potentially hazardous traffic.
Step away from aviation for a moment and imagine the following remote backwoods analogy to better understand the advantages of ADS-B In. Imagine you are hiking in the wilderness and you become separated from your group. It is dusk and you are walking on a dark trail in an area where grizzly bears have been sighted recently.
As you approach a bend in the trail, you have an imaginary device that tells you there is a something lurking in the darkness around the bend. This device is analogous to a real TCAS display. Imagine now that, instead of the TCAS-like display, you have a device that informs you not only of the threat existence, but tells you the being’s identification (grizzly bear or companion), whether the creature is moving toward or away from you, and tells you its size and the speed at which it’s approaching.
The latter device is comparable to Garmin’s ADS-B In. Garmin, with 3 decades of innovative avionics production expertise and vast experience on the Garmin Pilot app, is prepared to offer ADS-B In traffic awareness solutions to business aircraft operators. Garmin has successfully incorporated ADS-B In traffic that is available with any Garmin installation.
The company’s ADS-B In traffic displays present nearby vehicles and aircraft on the ground and in the air, preventing surprises and reducing cockpit workload. Occurring every second, ADS-B position and target track updates improve SA in cockpits of operators equipped with ADS-B In.
Marty Rollinger has over 35 years of flight experience in 68 different aircraft. A career US Marine Corps pilot, he was a Liethen-Tittle Award graduate of USAF Test Pilot School. He is director of flight ops for a Midwestern operator and a member of the Falcon Operator Advisory Board.