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Air Navigation and Weather Services

Taipei FIR CNS/ATM
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• Foreword
• Plan Goal and Schedule
• CNS/ATM System Program Office (SPO)
• Plan Consultant
• Implementation Plan Contents
• Communication
• Navigation
• Surveillance
• ATM
• CNS/ATM Implementation Plan Progress Status
• Quarterly International CNS/ATM Development Status
• Vocabulary in CNS/ATM
• Vocabulary in Aeronautics
• Links

Surveillance

1.  Automatic Dependent Surveillance-Broadcast, ADS-B

ADS-B is a system that uses transmissions from aircraft, approximately once a second, to provide position, altitude, positional integrity, flight identity, 24-bit aircraft address, velocity, and other data that have been detected and computed by onboard aircraft sensors. Typically, the airborne position sensor is a GNSS receiver, or the GNSS output of a Multi-Mode Receiver (MMR). An ADS-B ground station uses a non-rotating omni-directional antenna to receive messages transmitted by the aircraft. ADS-B is designed as a multiple use surveillance technique for aerodrome surface, terminal, and en-route airspace, and is applicable to both ATC and aircraft-to-aircraft surveillance.

ADS-B is “line of sight” based surveillance and requires ground stations to receive data and transmit to ATMS. A single ground station can provide coverage out to approximately 250NM for en route, terminal, and aerodrome surface surveillance. ADS-B requires new equipage for aircraft and ADS-B accuracy and integrity is subject to the source of the navigation data (usually GNSS). ADS-B offers benefits in:

a.  Extending existing coverage to areas of the Taipei FIR not currently covered by radar

     surveillance including aerodrome surface surveillance.

b.  Providing redundancy to existing surveillance systems.

c.  Increasing surveillance accuracy and consistency in tracking.

d.  Facilitating a reduction in capital and maintenance costs for surveillance infrastructure.

e.  Providing a starting point for airborne based spacing and separation procedures.

f.   Increase safety, capacity, and efficiency within the Taipei FIR for all airspace users that are

     equipped.

ICAO has identified ADS-B as a main component in future ATM surveillance and is actively supporting ADS-B implementation. ICAO has recently revised key documents such as PANS–ATM Doc 4444 to reflect the change from radar surveillance to also use ADS-B for 5 NM en route separation. This focus by ICAO is driven in a large part by the development and implementation work carried out by member States such as Australia and the US who are providing ADS-B based ATC services. An ADS-B Application is shown in Figure 1.

Figure 1. ADS-B Application

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