Communication
1. ATS Service Network (ASN):
CNS/ATM implementation standard proposed by ICAO for ground-ground data link communications specifies that it must connect through ATN routers between FIRs (the ATN router has been implemented by an AMHS sub-program), but does not provide specifications for intra-FIR communications. Because of this proposal and because the existing Asynchronous Transfer Mode (ATM) network technology is quite mature with circuit reroute capability, this ATM network technology will be chosen by CAA as the basis for ASN implementation. The reliability of the ASN network will be significantly improved in the future and the workload of the maintenance personnel will also be reduced. The system implementation will be accomplished in 4 phases. Relevant implementation details are summarized below:
Phase I ：Beginning in 2003, implement the ATM backbone network to connect ATS facilities, including towers, communication maintenance units, aerodromes and airlines, etc.
Phase II ：From 2005 to 2006, complete Northern digital microwave ring data protection routing system. The system will connect Taoyuan Aviation Facilities Sector, Da-dong Mountain, Linkou, Songshan Aerodrome, Da-tun Mountain and Xiang-An Building to form a two-way ring data protection routing system. This system will ensure that ATC data will continue to be transmitted if there is a failure in any section of the network.
Phase III ：From 2006 to 2007, extend the ASN network to the new North and South ATS Parks. The expansion of ASN in this phase will also include upgrade of the ASN with NGSDH functionality to meet the new ATMS networking needs.
Phase IV ：Begin to implement satellite links for redundancy in 2009.
Network configuration is shown as Figure 1.
Figure 1 ASN Network configuration
2. ATS Message Handling System (AMHS):
According to the planning concept of ICAO, the Aeronautical Information Message Switching (AMHS) was to be broadly used in the Asia-Pacific Region by 2005. However, on a regional scale, this has not occurred. As of December 2007, only Taipei FIR has officially deployed AMHS in the Asia-Pacific Region.The CAA has planned the AMHS implementation in accordance with the ICAO CNS/ATM plan and augmented with the specific requirements of the Taipei FIR. The AMHS implementation is part of the Communications Sub-plan of the CNS/ATM Plan. Currently, Hong Kong and Fukuoka FIRs are connected to Taipei FIR through the AMHS Bridge and Gateway, while Taipei and Manila FIRs are connected through the AMHS Gateway. The AMHS system will connect directly to the adjacent FIRs’ AMHS systems when they are implemented.
The AMHS system will be implemented on ATN and replace the current AIMS system. The AMHS system will
exchange information with other FIRs in the future. In the Asia-Pacific Region, most countries have
not implemented the AMHS system. The CAA will connect with these countries through the AMHS Bridge as
part of the AMHS system, to provide uninterrupted services.
The AMHS system was accepted in October 2005. The CAA completed the internal and external
users’ transition from November 2005 through February 2006, when the CAA formally began to provide AMHS services.
The Asia/Pacific ATN network configuration is shown as Figure 2,
and Figure 3 depicts the AMHS terminal user network
configuration in the CNS/ATM plan.
Figure 2 The Asia/Pacific ATN network configuration
Figure 3 AMHS terminal user network configuration
3. Voice/Data Link Meteorological Information for Aircraft In Flight and
Automatic Terminal Information Service (Voice/Data Link VOLMET & ATIS):
According to the standards contained in ICAO Annex-3, the meteorological authority should report meteorological information including METAR, SPECI, TAF, SIGMET, AIRMET and air-reports not contained in SIGMET, etc., for aircraft in flight. This service is called the Meteorological information for aircraft in flight (VOLMET).
In order to comply with ICAO international standards, ANWS
has made a decision to implement Voice / Data link VOLMET
and incorporate the program into the CNS/ATM Plan. In addition
to planning the Voice/Data link VOLMET system, the CAA decided
to upgrade the current ATIS systems in Taoyuan, Kaohsiung, and
Songshan aerodromes. After the commissioning of AMHS, the upgraded
system is able to extract the meteorological text from AMHS and
incorporate some additional system functions as suggested by controllers,
the CAA plans to implement Voice/Data link VOLMET and ATIS via system
integration to provide complete meteorological information service and
promote operational efficiency in Taipei FIR at aerodromes, in terminal
airspace and in en-route airspace. The final system acceptance of this program
has been completed in December 2005 and the system is now operational.
The structure of Voice / Data Link VOLMET and D-ATIS is shown in Figure 4.
Figure 4 Structure of Voice / Data link VOLMET and D-ATIS
4. Selection of Data Link Service Provider (DSP):
The DSPs offer global data link services. Through their air-ground (radio and geostationary satellites) and ground-ground communication service networks, aircraft operators can connect to the air traffic service information stations and to terminals through the DSPs’ air-ground and ground-ground communication service networks. DSPs offer a sound network management control system, and can service flights using different ACARS specifications (AEEC, 620, 623).
At present most international aircraft have ACARS capability, and use it to communicate via air-ground data-link with the data communication ground stations. Because data-link service provides worldwide coverage, system facilities and network maintenance require large investment. Most countries do not estiblish their own global data-link service network; instead, they lease data link services from SITA and ARINC. The first phase of this program began to provide the “Digital Airport Terminal Information System (D-ATIS)” data link service in June 2004. The second phase of this program began to provide the “Digital Meteorological Information for Aircraft In Flight (D-VOLMET)” data link service in December 2005. Data link communications system configuration is shown as Figure 5.
Figure 5 Data link communications system configuration
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