AERONAUTICAL MOBILE COMMUNICATIONS PANEL (AMCP)
Working Group C – 5th meeting
Kobe, Japan
15 – 25 October 2002
Proposed changes to draft report to AMCP/8 on communication scenarios
Presented by the Secretary
This document contains a proposal for changes to the report to AMCP/8 on communication scenarios that is currently under development by WGC/5. The proposals address the original Sections 1-7 and 12.
1. BackgroundIntroduction
The present ambiguity on the roles of the CNS elements in the future global Air Traffic Management System increases the technological and investment risk to the aviation community for the necessary supporting communication, navigation and surveillance infrastructure. Not having clear stated operational requirements causes the development of various CNS variants to meet perceived operational requirements in the anticipation that it will at least meet a subset of the overall requirements. For the communication element this has led to the development and standardisation of competing technologies for voice and data link services with complementary and overlapping characteristics.
Initially these systems might bring early benefits within the present operational practices, however it could result in a patchwork of different Regional and National communication networks increasing the overall infrastructure costs whilst reducing the quality of service.
As a result of growing air-ground communications requirements and of the potential spectrum scarcity created by claims on aeronautical spectrum by non-aeronautical users, efficient utilization of the aeronautical spectrum by communication systems is becoming a critical aspect of air navigation planning.
Since the 10th Air Navigation Conference (1991), ICAO has introduced into Annex 10 a number of new air-ground communication technologies. Implementation of these technologies is currently underway and contributes to increasing the aggregate aviation spectrum requirements. At the same time, conventional air-ground voice communicaiton systems continue to operate, still representing the main medium for operational communications.
With particular regard to the VHF band, AMCP/5 (21 – 30 April 1998) supported the proposal for developing a new approach for the future aeronautical VHF systems in the post-2010 time frame and developed a recommendation (AMCP/5 Recommendation 4/2) calling for an ICAO body to be taske, inter alia, to:
AMCP/7, recognizing the risk of the proliferation of system solutions, has assigned the following tasks to ICAO WG-C:
a)to explore the long-term system requirements for aeronautical VHF systems in the light of the ATM concept, scenarios for all flight and operational requirements for implementation for beyond 2010 to be developed by the ATMCP, and
;
b)to explore the likely airspace user needs for aeronautical VHF systems beyond 2010.
AMCP/7 (22 – 30 March 2000), assigned these tasks to AMCP Working Group C. Accordingly, Working Group C has developed the present document as an input to AMCP/8.
In the course of the document’s development, it was recognized that, while the tasksThe tasks are related identified by AMCP/5 and referred by AMCP/7 to WGC specifically addressed to the VHF systems after 2010, however they can’could nott be properly addressed performed without due consideration to aeronautical communications services in other radio frequency bands, as the total aeronautical communications requirements would be met by a combination of systems operating in different bands..
It was also recognized that the introduction of the future communication infrastructure should be guided by operational needs (expressed in terms of required communications system performance) and should be based on the most cost-effective infrastructure that met such needs. Furthermore, considering the lead-time required to deploy the necessary infrastructure for a successful implementation, it was recognized that transition planning was essential to provide a road map towards a common global interoperable communication infrastructure which could evolve in capacity and services to meet the requirements dictated by the expected growth in air traffic.
Improved communication is the enabler and not the end-goal, hence communication is a pure cost element within the overall CNS/ATM system concept. Therefore the introduction of the future communication infrastructure should be guided by:
The operational need in terms of performance and capacity and
The optimum infrastructure to meet this need.
Considering the lead-time required to deploy the necessary infrastructure for a successful implementation, transition planning is essential to provide a road map towards a common global interoperable communication infrastructure which can evolve in capacity and services with the air traffic growth.
2.0 Introduction to the report
Thise report is intended to make an inventory of the problems solutions that the aviation community is has developed for the facing through the introduction of communication technology, with the objective to provide guidance towards a harmonized global communication infrastructure.
The reportIt provides an overview of the present situation that is being used as the basis for the assessment of various implementation scenarios towards 2010 – 2015.
through an assessment of already ICAO standardized systems. These scenarios are analyzed on their merits in conjunction with the developments in the mobile communication industry of 2.5, 3 and possibly 4th Generation systems.
3.0 Scope of report
The scope of the report is basically constrained to includes all the communication services which supportfor Air Traffic Management (ATM), including Air Traffic Control (ATC), Air Traffic Services (ATS) and Airline Operational Communication (AOC). with the While VHF communication systems are as the initial original focal point of the report, . However, since frequency, increased services and capacity needs and integration aspects are involved otherother aeronautical communication services and systems were felt necessary to be are considered included in the considerations, where necessary to support an integrated view of future aeronautical communication systems development and implementation..
Within the ATM CNS service elements only the Communication service element and the Surveillance service element are considered. . Furthermore, the sSurveillance service element isfunctions are only considered to the extent that it isthey are supported through a data communication link system. Although the it is expected that Nnavigation services functions will be increasingly provided through data linkscommunication, nNavigation services functions are not addressed as it is anticipated that they 4will be supported through an separate infrastructure separate from the communication infrastructure.
While thisThe report is written intended as to be a self-contained document, supporting material with the caveat that appropriate qualitative and quantitative statements are documentedis provided in the list of references at Appendix X material.
4.0 The events since the 10th Air Navigation Conference2. Background
2.1 10th Air Navigation Conference
The 10th Air Navigation Conference, held in September 1991, endorsed the concept for a future air navigation system as developed by the Future Air Navigation Systems (FANS) Committees, that would meet the needs of the civil aviation community well into the next century. The FANS concept later became known as the communications, navigation, surveillance/air traffic management (CNS/ATM) systems. As stated in ICAO Document 9750 (Global air navigation plan for CNS/ATM systems), CNS/ATM is “the vision developed by ICAO with the full cooperation of all sectors of the aviation community to accommodate the future needs of international air transport”.
The results of the Conference were summarized in a set of recommendations covering the full spectrum of CNS/ATM activities, which continue to offer guidance and direction to the international civil aviation community as they plan and implement the technical and operational aspects of CNS/ATM systems.
In particular, Recommendation 3/2 - Development of SARPs for aeronautical data links, recommended that “ICAO ensure that SARPs for all forms of air ground data links, whether terrestrial or satellite-based, are completed in a timely manner to enable States to implement the appropriate systems for use in airspace of their responsibility.”
2.2 Special Communications/Operational Divisional Meeting (1995) (SP COM/OPS/95)
Subsequent to the 10th ANC, the Special Communications/Operational Divisional Meeting (1995) (SP COM/OPS/95) considered improvements in VHF spectrum utilization, by assessing the magnitude of the VHF frequency band congestion and on the basis of the available studies on possible solutions to relieve the congestion.
The meeting agreed on a number of improvements in the VHF communication spectrum utilization, both by existing and new systems. In particular, the meeting agreed on some near term improvements, based on 8.33 kHz channel spacing and developed Recommendation 6/1, requesting ICAO to amend Annex 10 to include the SARPs for the 8.33 kHz channel spacing DSB AM voice for implementation in areas with severe frequency congestion. It also agreed (Recommendation 6/2) that ICAO should expedite work on the 25 kHz TDMA integrated voice and data link system and (Recommendation 6/3) that ICAO should expedite the development of operational requirements and appropriate SARPs for data links to support navigation and surveillance elements of CNS/ATM applications. The meeting also recognized that any impact from the proposed new systems on other areas not affected by VHF frequency congestion must be minimized, and that ICAO should take the necessary actions to ensure that harmonized planning and implementation of new VHF ground and airborne sub systems are developed at the regional level.
2.3 Amendments to Annex 10
On the basis of the recommendations developed by the 10th Air Navigation Conference and the SP COM/OPS/95, ICAO embarked on an extensive plan of SARPs development for air-ground data links, mainly conducted through AMCP, which led to the inclusion of a number of air-ground data links in Annex 10 to the ICAO Convention.
In particular, the following Amendments to Annex 10 SARPs were developed:
Amendment 70 (effective 9 November 1995), including new SARPs for the Aeronautical Mobile-Satellite Service (AMSS);
Amendment 71 (effective 7 November 1996), including specifications for the Mode S subnetwork of ATN, material relating to the introduction of 8.33 kHz channel spacing, changes to material related to the protection of air-ground communications in the VHF band and technical specifications relating to the RF characteristics for the VHF digital link (VDL);
Amendment 72 (effective 6 November 1997), including SARPs and guidance material for VHF digital link (VDL);
Amendment 73 (effective 5 November 1998), including material relating to the ATN and changes to specifications of the Mode S subnetwork.
Amendment 74 (effective 4 November 1999):, including SARPs for HF data link;
Amendment 75 (effective 2 November 2000), including changes to the AMSS SARPs introducing a new antenna type, a new voice channel type and enhanced provisions for interoperability among AMSS systems; changes to the VDL SARPs to reduce potential interference to current VHF voice communication systems caused by VDL transmitters; and changes to the VHF voice communication SARPs to enhance immunity to interference from VDL transmitters on board the same aircraft.
Amendment 76 (effective 1 November 2001, including ATN system management, security and directory services; integrated voice and data link system (VDL Mode 3); and data link satisfying surveillance applications (VDL Mode 4);
Amendment 77 (effective November 2002), including changes to SARPs addressing issues encountered during tests and operational trials of the Mode S data link subnetwork.
[Also mention review of doc 9750]
3. Present situation
3.1 Introduction
Considering the difficulty to state future operational performance requirements for mobile communication and surveillance,
As a basis for an evolutionary approach way has to be sought to improve the aeronautical communication capability and capacity, this chapter contains. Before this, an inventory of presently operating systems and ongoing and planned trials for newly standardized technologies is needed.
Starting from the present operating voice systems, the first next step is becoming clearer. To support long range communication satellite communication services for voice and data and HF data link services are introduced. and the introduction of VHF VDL Mode 2 for non-time critical ATC data communications in higher density terrestrial traffic areas.
This chapter intends to make an inventory on the status of current ICAO standardized mobile communication systems, as part of the Annex 10, Volume III plus non ICAO standardized systems introduced to facilitate the transition from the present systema to the ICAO compliant systems.=
At present almost every ATS communication exchange is conducted by voice: ATC, ATS (ATIS, VOLMET…). .The supporting infrastructure supporting them is mainly based on the 25 kHz and 8.33 kHz VHF DSB-AM technologies. HF is also used in oceanic and remote regions.
For ATS, limited use is made of data communication using ACARS, ARINC 622, 623 Protocols over VHF, AMSS and HFDL. VDL Mode 2 is being introduced for non-time critical ATC data communications in higher density terrestrial traffic areas.
3.2 Systems under consideration
This section provides a high level technical and operational description overview of the ICAO standardized mobile ATS communication systems. Besides a brief introduction for each of them, the main technical information is categorized as a set of tables. The structure, scope and content of the tables have been defined in accordance with the objectives of this report. Note that every potential data sub-network system has toshall be ATN compliant (for data only).
General Systems overview
VHF 25 kHz and 8.33 kHz DSB-AM
25 kHz channel spacing
VHF 25 kHz DSB-Amchannel spacing supports current voice communications between controllers and pilots, pilot and pilots, and broadcast Flight Information Services (e.g. ATIS), and as well as airline operation center and pilots communication. Transmission is made on a double side band (DSB) amplitude modulation (AM) carrier. The frequencies are selected within the band 118 117.975 – 137 MHz. The lowest assignable frequency is 118 MHz and the highest 136.975 MHz
The frequencies are selected within the band 118 – 137 MHz.
8.33 kHz channel spacing
8.33 kHz channel spacing supports voice communications between controllers and pilots. 8.33 kHz channel spacing It was recognized by SP COM/OPS/95 as the medium near term solution to alleviate the European congestion in the VHF communication band and was implemented starting 7th October 1999 within the FIR/UIR of the core Europe (Austria, Belgium, France, Germany, Luxembourg, Netherlands, Switzerland), where. cCarriage of 8.33 kHz channel spacing R/T equipment is then currently mandatory for all aircraft when operating or capable of operating above FL 245. 8.33 supports voice communications between controllers and pilots. Mandatory carriage of 8.33 kHz equipment will [has been] be extended to additional airspace over FL245 of 21 States as from October 2002. 8.33 kHz equipment usage below FL 245 is currently considered under consideration in Europe (see programs and future activities section).
The frequencies are selected within the band 117.9758 – 137 MHz
Other channel spacing
Note: iWhile 25 kHz equipment is in use in all regions, in some regions of the World, aircraft VHF radios are still flying operating with 50 kHz or even 100 kHz channel spacing.
VHF radios.
HF SSB voice
HF SSB (single side band) is operated in the frequency bands band between 2.85 MHz and- 22 MHz, that arewhich is allocated to the aeronautical mobile (route) service. This system supports voice communication exchanges in oceanic and remote regions.
HF dData lLink
ICAO SARPs for HF data-link are applicable from 1999. HF data link uses the same frequency bands as HF voice. between the 2.85 MHz - 22.00 MHz range. This system uses a bit-oriented air-ground protocol which conforms to the open system interconnection (OSI) model and is designed to function as a sub-network of the ATN, but can also operate outside ATN..
The data link appears to offer a practical means of data communications that could be utilized on a stand-alone basis or to backup or complement to satellite data link. In particular, HF data-link can provide coverage at high latitudes, where there are some satellites limitations (GEO).
The frequencies are selected within the band 2.85 - 22 MHz.
AMSS
ICAO SARPs and guidance material for the AMSS became applicable in 1995. Subsequent updates became applicable in 2000. The AMSS provides voice and data services via geostationary satellites to all types of aeronautical users and operates in the Mmobile sSatellite serviceSystem L-bands (1 545 - /1 555 – and 1 646.5 - /1 656.5 MHz). The Inmarsat global satellite system supports AMSS and provides coverage of most of the world excluding polar regions. Another system, the Multifunctional Transport Satellite (MTSAT) is planned to be launched in 2003 to operate in the Pacific region (see below).
To ensure adequate protection for safety and regularity of flight messages provisions are included in the SARPs to ensure that these messages have priority and pre-emption over other non-safety aeronautical users. Exclusive spectrum for AMSS has gradually been reduced to zero in the ITU process mainly due to limited utilisation of the band. However While AMSS has priority access to the MSS spectrum for safety and regularity through provisions in the Radio Regulations, practical implementation of the provisions in situations where the spectrum is in use by non-aeronautical service providers has been questioned by the aviation community and needs to be confirmed.
.
Around 3000 aircraft have been equipped with satellite communications systems for ATS communications as well as AOC and APC. These initial implementations although not fully compliant with the AMSS SARPs, enables the ICAO CNS/ATM system to be introduced in areas of the world were previously not possible. AMSS is designed to be a sub-network of the ATN but most of the current implementations are based on the use of the airline industry ACARS standard.
ACARS Data Link
The Aircraft Communications Addressing and Reporting System (ACARS) was originally (around 1978) based on the 25 kHz VHF -DSB-AM system, and designed for AOC services. This It is a nonnot an ICAO standard system . (e.g. ACARS/ARINC 622 in the Pacific and ACARS/ARINC 623 in continental Europe).
Since With the introduction of protocols like ARINC 622, which provides addressing functions and a CRC (Cyclic Redundancy Check) and ARINC 623, which provides message definitions, the ACARS message formatit has been increasingly used in most ICAO regions over VHF, HF, and AMSS systems. Limited ATC applications such as Departure Clearance and ATIS are in extensive use in North America and are being implemented in other rRegions. ARINC 622/623 were initially developed to improve ACARS over AMSS for ATC oceanic service in the South Pacific using FANS 1. ARINC 622 provides addressing functions and adds a CRC (Cyclic Redundancy Check).