Система АЗН-В (ADS-B)

Overview

Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance technology in which an aircraft broadcasts its GPS-derived position, altitude, velocity, and identification continuously to ATC ground stations and to other equipped aircraft (ADS-B In). Unlike primary radar, which actively interrogates aircraft, ADS-B is "automatic" (no pilot or controller action required) and "dependent" on the aircraft's own navigation source (GPS) rather than ground-based ranging. This distinction enables higher position accuracy (GPS vs. radar), faster update rates (once per second vs. once per 5–12 seconds for radar), and coverage in areas beyond radar range — oceanic routes, mountainous terrain, and polar regions.

The FAA mandated ADS-B Out (transmitting) for operations in most US controlled airspace from January 1, 2020. EASA required ADS-B Out for European airspace from June 2020. ICAO has promoted a global mandate framework through its Global Air Navigation Plan. ADS-B Out is now required on virtually all commercial aircraft worldwide, ending the era of purely radar-based surveillance. The complementary ADS-B In capability — receiving and displaying traffic from other aircraft — is not yet mandated but is increasingly fitted, enabling airborne traffic situational awareness beyond TCAS range.

How It Works

ADS-B Out uses the aircraft's Mode S Extended Squitter (ES) transponder operating on 1090 MHz to broadcast a standardized message set defined by ICAO Doc 9684. Each message contains the ICAO aircraft address (the 24-bit unique identifier), GPS position (latitude/longitude), altitude (barometric and geometric), ground speed, track angle, vertical rate, and flight identification. Messages are broadcast approximately once per second for airborne aircraft.

Ground stations receive these broadcasts and forward them to ATC automation systems (such as STARS or ENROUTE in the US), where they are fused with secondary radar returns in a process called multi-lateration (MLAT) and ADS-B fusion. The fused track is more accurate and available sooner after takeoff than radar alone. In oceanic airspace beyond radar coverage, ADS-B via Iridium or Inmarsat satellite links (ADS-C, a related but distinct contract-based system) gives ATC position reports every 15 minutes, compared to voice position reports every 10–15 minutes in the pre-ADS-B era.

Key Components

• Mode S Extended Squitter Transponder: The core ADS-B Out transmitter, broadcasting on 1090 MHz at 200–500 W. Must meet RTCA DO-260B (US) or EUROCAE ED-102B (Europe) performance standards.
• GPS/GNSS Position Source: ADS-B Out requires a GNSS position source meeting RTCA DO-316 or TSO-C166b accuracy standards — typically the aircraft's existing FMS GPS or a dedicated ADS-B GPS unit. Horizontal accuracy must be NACp ≥ 8 (<0.05 nm, 95%).
• ADS-B Out Avionics (Squitter Generator): The avionics unit (often integrated into the transponder) that formats the GPS position and other state data into the 1090ES message format and schedules transmissions.
• ADS-B In Receiver (optional): A 978 UAT or 1090 MHz receiver that captures broadcasts from other aircraft and ground stations (Traffic Information Service-Broadcast, TIS-B; Flight Information Service-Broadcast, FIS-B), displaying traffic and weather on a cockpit display.
• Cockpit Traffic Display (ADS-B In): Typically the ND or a dedicated traffic display, showing ADS-B-equipped traffic with precise position, altitude, and intent beyond the TCAS active interrogation range.

Aircraft Applications

• Boeing 737-800: Retrofitted with ADS-B Out via upgraded Mode S Extended Squitter transponders; displayed on the ND traffic page alongside TCAS targets, with ADS-B In on selected operators' aircraft.
• Airbus A320-200: ADS-B Out integrated into the existing Mode S transponder via software upgrade for most in-service aircraft; newer production includes ADS-B Out as standard with the Thales TRT-800 or Rockwell Collins TDR-94D.
• Boeing 787-9: Designed with ADS-B Out as a standard feature from EIS; the Common Core System integrates ADS-B with TCAS Hybrid Surveillance, reducing active interrogations of ADS-B-Out-equipped traffic and extending surveillance range.
• Embraer E190-E2: ADS-B Out standard from service entry (2018); ADS-B In capability integrated with the Honeywell Primus Epic 2 avionics suite for in-cockpit traffic situational awareness.

Advantages and Limitations

ADS-B Out provides ATC with aircraft position updates every second rather than every 5–12 seconds for radar, enabling tighter separation standards and improved en-route efficiency. Coverage extends to oceanic and polar routes, enabling ATC to apply reduced vertical minima (RVSM) and performance-based navigation procedures globally. ADS-B In capability, when implemented, gives aircrews a significantly larger traffic picture than TCAS alone, theoretically extending situation awareness to 100+ nm ahead on oceanic tracks.

The primary limitation of ADS-B is its dependence on the aircraft's GPS — GPS jamming or spoofing can corrupt ADS-B position reports, a growing concern near conflict zones. The system relies on the aircraft to self-report accurately; a faulty GPS or avionics failure can lead to erroneous position broadcasts that are difficult for ATC to detect. Unlike primary radar, ADS-B provides no independent position verification. Cybersecurity risks associated with the unencrypted 1090 MHz broadcast are under active study by ICAO and national authorities, with authentication mechanisms proposed for future systems.