The CNS Ground Station
Components of a CNS Ground Station:
The CNS ground station is the heart of an air-ground data communications system. It is much more than a data radio because it manages the interface between the air-ground data links and the ground based applications. Traditional ACARS systems carry Air Operational Control (AOC) messages between airline host computers and commercial aircraft. Future systems will support a wider variety of communications including GPS and radar target position reports, Air Traffic Control (ATC) messages, and Differential GPS corrections.
- Data routing and protocol conversion
- Upper-layer protocol implementation
- Remote management and alarms, logging
- May include any or all data link technologies>
- Ground Interfaces
- WANs - anything from SLC (ARINC, SITA) to Internet
- LANs - exchange information with the Tower, dispatch, and other airport systems
- Special - AMASS/ASDE-3, SSR, ground vehicle tracking, Differential GPS ground station ...
- UPS, redundancy, hot-standby, cold-standby, spares ...
Example: A Proposed Stand-alone ACARS System
In this example a few VHF data communications sites are strategically placed in a country to provide the coverage and redundancy desired. Each data communications site has one or more data link transceivers providing the physical and channel access protocol layers and a CNS Ground Station computer providing the link and networking protocols. These sites are linked to a central hub which provides system services and links to the end users.
Note that this system could easily support any of the data link technologies indivifually or simultaneously. This provides a transition capability for ACARS aircraft.
Example: Single Mode Block Diagram 1
An uninterruptable power supply with backup generator capable of powering the site as required to meet site availability goals will also be required.