Automatic Dependent Surveillance-Broadcast (ADS-B)

ADS-B Out-equipped aircraft broadcast precise information, including position, velocity, and identification, to ground stations and other aircraft every second. This continuous data stream enables air traffic controllers to monitor aircraft movements with greater accuracy and timeliness, even in areas where traditional radar coverage is limited.

Aircraft operating in most controlled airspaces are required to be equipped with ADS-B Out to comply with FAA, EASA regulations.

ADS-B In-equipped aircraft receive a wealth of information directly in the cockpit, including:

• Traffic Information Service–Broadcast (TIS-B): Displays positions of nearby aircraft, enhancing situational awareness.
• Flight Information Service–Broadcast (FIS-B): Provides weather data, Notices to Airmen (NOTAMs), and other critical flight information.
• Automatic Dependent Surveillance–Rebroadcast (ADS-R): Facilitates communication between aircraft operating on different ADS-B frequencies.

Traditional radar updates aircraft positions every 5 to 12 seconds. In contrast, ADS-B Out transmits real-time data – position, velocity, and identification – every second, providing air traffic controllers with near-instantaneous updates. This continuous flow of information allows for more precise spacing and routing, particularly in non-radar environments like the Gulf of Mexico, Colorado's mountainous regions, and Alaska's lower altitudes.

Pilots equipped with ADS-B In gain access to Traffic Information Service–Broadcast (TIS-B), which delivers real-time traffic data, including altitude, ground track, speed, and distance of nearby aircraft within a 15-nautical mile radius and up to 3,500 feet above or below their position. This capability significantly enhances pilot awareness and collision avoidance.

With a Universal Access Transceiver (UAT) ADS-B In receiver, pilots receive Flight Information Service–Broadcast (FIS-B), providing graphical weather displays, Notices to Airmen (NOTAMs), and alerts about significant weather activity. This information is broadcasted directly to the cockpit, offering pilots a comprehensive view of current conditions.

ADS-B Out operates on two frequencies: 1090 MHz and 978 MHz. The Automatic Dependent Surveillance–Rebroadcast (ADS-R) service ensures interoperability between these frequencies, allowing aircraft operating on different ADS-B links to share traffic information, thereby enhancing overall situational awareness.

The precise GPS-based surveillance provided by ADS-B enhances search and rescue efforts by offering more accurate last-known positions of aircraft. This capability reduces the critical window of time involved in search and rescue operations, particularly in challenging terrains where radar coverage is limited.