ADS-B Tracker: Understanding and Utilizing Automatic Dependent Surveillance-Broadcast Technology

ADS-B tracking has gotten complicated with all the In versus Out mandate debates, the receiver setup community discussions, and “how FlightAware and Flightradar24 actually get their data” questions flying around. As someone who has spent years following ADS-B technology development and the specific technical and regulatory aspects that determine how aircraft surveillance works in modern airspace, I learned everything there is to know about ADS-B trackers. Today, I will share it all with you.

But what is ADS-B tracking, really? In essence, it’s a surveillance system where aircraft use GPS to determine their own position and then broadcast that position — along with identification, altitude, speed, and heading — on 1090 MHz for anyone with a receiver to pick up. But it’s much more than flight tracking for enthusiasts. For air traffic controllers, airlines, and pilots, ADS-B provides more accurate and more frequent position data than radar, and at lower infrastructure cost over remote and oceanic areas where ground radar doesn’t reach.

How ADS-B Works

Aircraft equipped with ADS-B Out transponders use GPS receiver data to generate position reports and broadcast them automatically at approximately one-second intervals. The broadcast includes position, altitude above mean sea level, groundspeed, track, vertical rate, and the aircraft’s ICAO 24-bit address (which maps to the registration). Ground stations operated by FAA and private networks receive these transmissions. Other aircraft with ADS-B In receivers can also receive them directly. Don’t make my mistake of assuming ADS-B position reports are as accurate as the GPS source data — at least if you’re using ADS-B data for precision applications, because the position accuracy depends on the quality of the GPS receiver in the aircraft and on how recently the transponder was calibrated.

• Position — Latitude and Longitude derived from GPS
• Altitude — Barometric altitude, GPS altitude, or both depending on equipment
• Groundspeed — Velocity over the ground in three dimensions
• Identification — ICAO 24-bit address, squawk code, flight ID
• Heading — Track angle over the ground

ADS-B Out and ADS-B In

ADS-B Out is the transmit function — the aircraft broadcasting its state vector. The FAA mandated ADS-B Out for aircraft operating in Class A, B, C airspace, and above 10,000 feet MSL starting January 2020. ADS-B In is the receive function — the avionics that allow the aircraft to receive and display traffic from other ADS-B Out aircraft and weather data uplinked from ground stations (via FIS-B). ADS-B In is not mandatory but provides significant traffic situational awareness benefits, particularly in Class E and Class G airspace where ATC radar coverage may be limited.

Setting Up an ADS-B Receiver

The entry-level ADS-B receiving setup uses an RTL-SDR (Software Defined Radio) USB dongle, a dedicated 1090 MHz antenna, and software like dump1090 or Virtual Radar Server running on a Raspberry Pi or any Windows/Linux/Mac computer. That’s what makes the home ADS-B receiver community endearing to aviation and electronics enthusiasts — the full receive-decode-display pipeline can be built for under $50 and shared with flight tracking networks like FlightAware and Flightradar24 in exchange for premium access. Range depends on antenna height and local terrain — clear line of sight to the horizon extends range substantially.

Components Needed

• SDR Receiver — RTL-SDR dongle or purpose-built ADS-B receiver
• Antenna — 1090 MHz tuned antenna provides better performance than generic SDR antennas
• Software — dump1090, Virtual Radar Server, PiAware, fr24feed
• Computer — Raspberry Pi works well; any device running Linux, Windows, or Mac OS

Flight Tracking Applications

FlightAware, Flightradar24, and ADS-B Exchange aggregate data from thousands of receiver stations worldwide, providing near-global coverage for ADS-B-equipped aircraft. ADS-B Exchange specifically serves as a reference for unfiltered data — it doesn’t honor blocking requests from operators who prefer their flights not be publicly tracked. For aviation professionals, these platforms provide operational awareness of traffic for flight planning, fleet monitoring, and incident reconstruction. For enthusiasts, real-time and historical track data is the product. First, you should understand the gap between ADS-B coverage and actual traffic in oceanic and remote areas — at least if you’re trying to track specific flights over the Pacific or polar routes, because satellite-based ADS-B (Aireon’s space-based ADS-B network) now provides coverage that ground stations can’t reach, but not all tracking services incorporate satellite-derived ADS-B yet.

Future of ADS-B

Satellite-based ADS-B surveillance through Aireon’s system — hosted on Iridium NEXT satellites — provides global aircraft tracking including oceanic and polar regions. This fills the coverage gap that ground-based networks can’t reach and has been operational since 2019. UAS integration is the next ADS-B frontier: equipping drones with ADS-B Out enables ground-based and airborne receivers to see drone traffic, which is a prerequisite for safely integrating high-density commercial drone operations into controlled airspace. Remote ID regulations for drones in the US parallel the ADS-B mandate for manned aircraft, establishing a baseline visibility requirement for unmanned traffic management.