Automatic Dependent Surveillance-Broadcast (ADS-B) is a technology used in aviation and aerospace to provide location information about aircraft to air traffic control and other nearby aircraft. It is a crucial component of modern air traffic management systems.

ADS-B works by using a combination of GPS (Global Positioning System) and a broadcast transmitter on the aircraft. The aircraft's GPS system determines its precise location, and this information is then transmitted to nearby receivers on the ground and in other aircraft. This transmission, or "broadcast," includes the aircraft's:

1. Location (latitude and longitude)
2. Altitude
3. Velocity (speed and direction)
4. Identification (call sign or aircraft ID)

The broadcast is received by ground stations and other aircraft equipped with ADS-B receivers, allowing them to track the aircraft's position and movement in real-time. This information is used for various purposes, including:

1. Air traffic control: To separate aircraft and provide more efficient routing and sequencing.
2. Collision avoidance: To alert pilots to potential conflicts with other aircraft.
3. Weather avoidance: To help pilots navigate around adverse weather conditions.
4. Search and rescue: To quickly locate aircraft in distress.

ADS-B offers several benefits over traditional radar-based air traffic control systems, including:

1. Improved accuracy: ADS-B provides more precise location information than radar.
2. Increased efficiency: ADS-B enables more efficient routing and reduced separation distances between aircraft.
3. Enhanced safety: ADS-B helps reduce the risk of collisions and improves response times in emergency situations.

There are two main types of ADS-B systems:

1. ADS-B Out: This transmits the aircraft's location and other information to ground stations and other aircraft.
2. ADS-B In: This receives broadcasts from other aircraft and ground stations, providing pilots with real-time traffic information.

ADS-B is becoming a global standard for air traffic management, with many countries adopting the technology to improve the safety and efficiency of their airspace.