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Communication

　

1.  ATS Service Network, ASN

The existing communication circuits (both voice and data) of current CAA ATS facilities use point-to-point dedicated leased lines. To increase the circuit availability and to provide redundancy, two leased lines are often run in parallel. Because of the large number of circuits, the workload on the maintenance personnel to ensure circuit availability is correspondingly high. The cost associated with circuit lease and maintenance represents a significant part of ANWS’s operational budget. With the advent of digital networking, there is a huge incentive to replace most of the leased circuits with a network dedicated to the CAA’s ATS-related traffic.

Asynchronous Transfer Mode (ATM) network technology is a mature technology, and it improves service availability by providing circuit rerouting to circumvent circuit failures. To meet the Taipei FIR’s intra-FIR communications requirements, the CAA has selected ATM network technology for the ATS Service Network (ASN). Furthermore, the increased reliability and maintainability of the ASN will significantly reduce the maintenance workload.

To cope with unexpected interruptions on ground circuits, which would normally cause the stoppage of the ground-ground communications network service, satellite communications could be included as part of the ASN to provide backup connections from radar sites to the North and South ATS Parks, and to connect voice channels between ATS facilities. The plan is to implement satellite communications network service as the ASN Phase IV.

ASN will provide data transmission between all systems in the CNS/ATM program, including between the next generation ATMS and its peripheral support system. Network security will play a very important role and will be enhanced with VPN and firewall technologies. This program will be implemented in the four phases described below:

a.Phase I:

Phase I is to implement the ATM backbone network. Phase I was implemented from 2003 to 2004 to connect ATS facilities, including towers, communication maintenance units, aerodromes and airlines, etc.

b.Phase II:

Phase II is to implement the 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 topology for th Northern digital microwave system to provide bi-directional routing protection. This system will ensure that ATC data will continue to be transmitted if there is a failure in any section of the network. Phase II was implemented from 2005 to 2006.

c.Phase III:

Phase III is to 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 III was implemented from 2007 to 2009.

d.Phase IV:

Phase IV was originally planned to implement satellite links for redundancy. The plan has been put on hold indefinitely due to reprioritization.

　

2.  ATS Message Handling System, AMHS

According to the planning concept of ICAO, the 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 was implemented to 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 and ATN. The CAA AMHS is connected with AFTN of the neighboring countries through the AMHS Bridge as part of the AMHS system, to provide uninterrupted services. Full AMHS connectivity through ATN can only be realized in the future when all neighboring countries have implemented AMHS and ATN.

During the first stage of the AMHS implementation, beginning in 2002, systematic investigation was planned and conducted; the preparation of system specification and bidding documents were finished in 2003. The contract was signed with Thales IS on 26 December 2003 through an open tender process. Spare parts were purchased at the end of 2004. 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.

After the completion of the North and South ATS Parks and ASN network expansion in 2009, the AMHS system was relocated to the new North ATS Park in May 2009.

　

3.  AMHS Spare Parts Procurement

To effectively maintain the AMHS system, the CAA together with Thales IS identified the inventory of spare parts that will be required to maintain the procured AMHS. The spare parts procurement was not in the original implementation plan. The CAA added an AMHS spare parts procurement program to the plan, using reserve funds from the CNS/ATM plan’s 2004 budget. The contract for the spare parts procurement was signed on 14 July 2004, and the spare parts procurement was completed in October 2005.

　

4.  Implementation of D-VOLMET and D-ATIS

In agreement with ICAO Universal Safety Oversight Audit Program (USOAP), the CAA established a Safety Oversight Audit Group in November 2002 to take charge of establishing safe management mechanisms for air traffic regulations, procedures, and air traffic services. This activity is being conducted in order to comply with international standards and to reach the ICAO safety level requirements. In terms of meteorological standards, the CAA has completed a review of the relevant standards and drafted an improvement plan to achieve compliance.

According to the regulations of ICAO Annex 3, the meteorological authority should report meteorological information including METAR, SPECI, TAF, SIGMET, AIRMET, and Special Air-reports not contained in SIGMET etc., to aircraft in flight. This service is called “VOLMET”. VOLMET service uses Very High Frequency (VHF) or High Frequency (HF) transmitters to broadcast voice meteorological information, or data link transceivers to provide data meteorological information, to aircraft in flight, including specific aerodromes’ meteorological information.

Because the CAA is not a member of ICAO, ICAO assigned Taipei FIR’s VOLMET broadcast service to Hong Kong. To achieve conformity with ICAO international standards, the CAA convened a meteorological service improvement program conference in February 2004, and resolved to implement Voice/Data link VOLMET and to incorporate the implementation plan for this system into the CNS/ATM Master 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 planed and implemented Voice/Data link VOLMET and ATIS via the air traffic 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.

　

5.  Data Link Service Provider Selection

The DSPs offer global data link service 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 set up their own global data-link service network; instead, they lease data link services from SITA and ARINC.

DSPs cooperate with the ICAO and participate in various development plans. They have actively revised and tested the network equipment and every interface of the ATN in order to provide extended information services through the ATN. They have also set up an infrastructure to serve CNS/ATM data link communication.

DSPs have offered data link communication services to airlines and air traffic service providers, giving their ATC units the ability to provide more efficient CPDLC, PDC, and AIDC through data link; this includes the ability to provide dynamic surveillance data to the cockpit. The CAA’s initial implementation of these services via a DSP is in line with ICAO FANS and relevant industry standards.

　

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