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									                      >           FREQUENTIS TECH:NEWS
                                  Netcentric Operations…The service oriented concept

                                  VoIP…Benefits to ANSPs
                                  S2EV…Safety and Security enhanced Voice
                                  Usability…Optimising the working environment

+++ netcentric operations +++ netcentric operations +++ netcentric operations +++

+++ netcentric operations +++ netcentric operations +++ netcentric operations +++
>We proudly welcome you to “Tech:News”

  3     Cross Domain
        Synchronisation >
        A study by Frequentis and
        Austrocontrol      H. Künig,
            G. Trausmuth, M.Sajatovic

  4     Netcentric Operations >
        A paradigm shift boosts
        the quality of safety critical
        applications          J. Prinz

  10    Humans in the loop >             > Hannes Bardach, Managing Director
        Usability as a Crucial
        Factor for Corporate
        Success          T. Piribauer
                                         Ladies and Gentlemen,
                                         More than 50 years of experience in working for the ATM community – that makes us
  11    Voice Recognition >              at Frequentis proud and best qualified to tackle future challenges. We feel respon-
        How to improve efficiency        sible for intensifying the dialogue with customers and partners about emerging
                              T. Zeh     topics bringing in our expertise, our spirit for innovations, and our extensive domain
  12    VoIP in ATC >
                                         Operational concepts for future ATM are therefore a highly important issue for
        Hope or Hype?
                                         Frequentis. Netcentric operations, a term that has been derived from a concept
                      W. Kampichler
                                         discussed in defence organisations for almost 10 years, aims for more flexibility and
                                         speed also in civil ATM. A study conducted by Frequentis together with Austrocontrol
  12    S2EV >                           in the course of the Eurocontrol OATA initiative features cross domain synchronisation
        Analog Voice with                and brings an idea of exchanging information in a highly divers infrastructure.
        enhanced Safety and
        Security         M.Sajatovic     We cannot speak about current ATM challenges without mentioning VoIP – please
                                         find our contribution to the ongoing discussion in this Frequentis TechNews –
                                         Hope or Hype?

                                         Furthermore, all throughout the Frequentis history we were and are aware of the fact
                                         that usability is a crucial factor for making a solution really successful. What is a
                                         system without its user? Can we really discuss future concepts and innovations with-
                                         out taking into considerations the users’ requirements and needs? Isn’t it rather the
                                         optimised combination of user and system that brings the “real” quality for the
                                         relevant solution? Our article to “Humans in the Loop” offers first answers to these
                                         questions and inputs for further discussions.

                                         At Frequentis it is our declared wish launch a dialogue or to start discussions – about
                                         usability, about future operational concepts, and about the many other fascinating
                                         topics which currently busy the ATM community.

                                         Therefore – if a particular article catches your interest or you would like to share your
                                         thoughts concerning a special issue – please do not hesitate to contact me
                                         directly at hannes.bardach@frequentis.com
RESEARCH                                                                                                                                                     3
>Exchanging information in a highly divers infrastructure

Cross Domain Synchronisation
A study conducted by Frequentis together                                                                                         ATFCM
                                                                                                                                 Air Traffic Flow and
with Austrocontrol in the course of                                                                                              Capacity Management
the Eurocontrol OATA initiative                                     ATC
                                                                                                          APOP                   APOP
                                                                    ACC                                                          Airport Operator
   Information sharing is a fundamental                                                                                          Aircraft Operator
enabler for the success of ATM processes. Lack                                                                                   A/C
of information sharing leads to well known                                                                                       Aircraft
                                                                                  Information                                    AIM
bottlenecks, in an environment that faces                   MIL                                                    AO            Aeronautical
exponential traffic growth throughout the                                        Infrastructure
                                                                                                                                 Information Management

years. Cross domain synchronisation, based on                                                                                    ATC TWR
                                                                                                                                 Air Traffic Control Tower
the new paradigm of information sharing, will                                                                                    MET
satisfy the ATM stakeholders’ needs for a                                                                                        Meteorology
                                                                  MET                                        A/C
strategic framework, where information of                                                                                        MIL
                                                                               ATC                                               Military
various kinds can be shared and managed in a                                   TWR
                                                                                                                                 ATC ACC
coherent manner. The technology to implement                                                                                     Air Traffic Control Area
                                                                                                                                 Control Centre
such a framework is already available, imple-
mentation rules and community standards               >Information Sharing Infrastructure
have to be defined now to provide standar-
dised access in a heterogeneous environment.        ownership and security throughout the life-       ICAO, to resolve the institutional, operational,
   Historically, various aviation domains           time of interoperability objects. The framework   technical, legal and last but not least business
have developed their own information                is based on the OATA Strawman Architecture.       related issues arising with the new paradigm
management culture independently, which             Different system architectures – centralized      of system wide information management
unwillingly created barriers between the            and clustered vs. distributed – are introduced    (SWIM) beyond existing domain boundaries.
domains. Pure system integration through            and constraints within and impacts on the com-        Although the study explores a number of
standardised communication interfaces did           munication infrastructure in terms of band-       possible options and their characteristics, it
not solve interoperability problems – gate-to-      width and response times have been identified     cannot draw a final conclusion at this stage.
gate interoperability can only be achieved          and discussed. Deeper analysis has shown that     All parties involved in the study agree that
through information integration, covering           no air-ground cross domain synchronization        there is a need for more detailed analysis,
three core processes: content management,           services will likely be widely deployed in        piloting and evaluation for confirmation of
acquisition, and dissemination of data.             the near-term (2012), while advanced ground-      the feasibility of the implementation options
   The technology of information sharing and        ground synchronization concepts and methods       presented.
integration is a prominent research and appli-      may well be in place then.                            The message to the decision makers is that
cation area. It dramatically gained momentum           The justification for implementation of an     information sharing across domains is to be
by the success of the Internet technology,          Information Sharing Infrastructure will be        considered as an enabler for consistency,
which became the basic motivation for new           given by higher information consistency and       interoperability, cost reduction and efficiency
technology proposals.                               reduced system life cycle cost for applications   of application system development. The “New
   Several technologies, popular, standardized      building on the newly created, standardised       Approach” of the Single European Sky regula-
and well understood, can be used to implement       infra structure. Transition to the new infra-     tion for interoperability comprising the regu-
distributed information systems, ranging from       structure for legacy systems will be achieved     lation, the implementing rules and community
middleware platforms to web services and grid       by support of existing interfaces and proto-      standards provides a perfect basis for the
systems. Middleware systems are used as an          cols by gateway functions.                        urgently required standardisation. It is of
abstraction layer for communication among              The focus of the information sharing           paramount importance to start the activities
heterogeneous systems and components. Web           approach is targeting for investment protec-      for standardisation of this infrastructure
services aim for inter-enterprise application       tion by optimised reuse of existing installa-     today, to boost current SWIM Activities from
integration through Hypertext Transport             tions, standardised access to the information     local to global level, at which airspace users
Protocols (HTTP, HTTPS) and a common data           sharing infrastructure, consistency of infor-     tend to operate.
representation through extensible markup            mation and a new interoperability standard
languages (XML). The study presents a concep-       fulfilling according to Single European Sky
tual framework for the implementation of cross      Regulations.                                                        Hubert Künig, Georg Trausmuth,
domain synchronization for ground-based and            It will be a challenge for stakeholders and                                    Miodrag Sajatovic
airborne systems, covering data transport, data     industry, as well as for the European
representation, quality of service, data            Commission and the related decision bodies in
    >A paradigm shift boosts the quality of safety critical applications

    Netcentric Operations
    Europe is moving towards the Single European Sky; a seamless airspace that is managed flexibly within Functional Airspace Blocks.
    In the United States the FAA incrementally implements the concept of Flexible Airspace Structuring. Starting with the most densely
    utilised airspaces this way of operating the airspace radically deviates from what how it was operated in the last decade. With
    flexible arrangements that can accurately be adjusted to the needs in distinct situations the airspace becomes more of a beating
    organism than the fixed structure it used to be.

    With air traffic control sectors changing their shape and physical dimensions, the supporting infrastructure on the ground is required to
    fully support these operations. Services have to be available in certain roles and duties rather than at a specific location. Flexibility,
    however, is not a sole concept of Air Traffic Management. It applies to other safety critical operations as well, thus making Netcentric
    Operations the solution of future safety-critical systems.

                                                                           G/G VOICE COMMUNICATION

                                                  Radio                                                 Radio

                                    VCS                                                                         VCS

                                     DATA                                                                        DATA

            SERVICE ISLAND                                                                                                         SERVICE ISLAND

                                              DATA EXCHANGE




                                                                                                                      DECISION MAKING CYCLE

                                                SERVICE ISLAND

      >figure 01_Traditional VCS-Systems
MARKET & SERVICES                                                                                                                                           5
>A paradigm shift boosts the quality of safety critical applications



                                      Client                                                                  Client

                                                                                                          Robust and globally interconnected
                                                                                                          Network Environment


                                                               Client                 Client                  Radio


  >figure 02_Frequentis VCS 3020XM Moving towards a Service-Oriented Architecture

Consumers need services to fulfil their duty                                  to the network that generate the features needed and the
at any applicable location                                                    network/communications infrastructure purely takes care that the
    Netcentric Operations is a term that has been derived from a              information is furnished to the right location with the negotiated
concept discussed in defence organisations for almost 10 years:               quality of service. However, from a user’s point of view this insight is
network-centric warfare. It basically aims for more flexibility and           not necessarily obvious any more.
speed in military operations. Although in civil ATM we do not require            Voice Communication Systems (VCS), equipment that provides
combating any principle goals including the increased speed and               tactical voice services today, are best described as service islands.
quality of OODA (observe, orient, decide, act), it may well transform         Most of their features are available within a single system at one site.
into a concept that serves all safety-critical services.                      Only a limited number of services are shared between those sites
    Netcentric Operation is a service-oriented concept. It puts the con-      (e.g. national ACCs), which can be summarised as basic G/G commu-
sumer (user, role) at the centre of the notion. A consumer requires a         nication services. In comparison, surveillance services (e.g. radar),
certain set of associated services, which vary over time, but which           planning tools (e.g. flight plan), or information services are not
may not be restricted to a certain place. A similar situation can be          restricted to distinct locations any more.
seen for the sensors and actuators (e.g. radar heads, radios).                   Netcentric Operation is not limited to voice services. It is the idea
Netcentric Operations simply denote a situation where no user                 to provide the controller with all services required to fulfil his duty
(i.e. controller) is required to operate on a specific (fixed wired) system   regardless of his physical position.
or even on a specific controller working position in order to get the
service needed. The user can be located at any workstation in the service     What are the Benefits of Netcentric Operations?
area. In that sense the service – be it radio, telephone or anything else        Netcentric Operations generate immediate benefits in the 2 major
– is provided at the “network connection”. Therefore, the notion pops         areas of all safety critical operations. It increases safety and efficiency
up that the service is emerging from the “network” cloud.                     in operation.
    But it is not the network or in other words the communications infra-        A service-oriented infrastructure allowing netcentric operations
structure that provides the service. There are applications connected         perfectly scales to different operational needs because it consists of
    >A paradigm shift boosts the quality of safety critical applications

    loosely coupled small entities like servers and clients. Due to their                  A service infrastructure for netcentric operations uniquely reduces
    size basic units introduce much less complexity than big systems.                  the “network distance” between sites as it offers service access from
    Consequently, they are more stable and losing one of these units does              any site via different network infrastructures, resulting in a large
    not lead to a full service outage. In addition, a netcentric operations            virtual centre enabling net-centric operations. Net-centricity is a
    infrastructure does not require a single switch-on step. It can be com-            robust, globally interconnected network environment (including
    missioned on an incremental basis and thus allows it to flexibly                   infrastructure, systems, processes, and people) in which data is
    adjust to the operational needs.                                                   shared timely and seamlessly among users, applications, and
        The service orientation allows requesting services at any entity in            platforms. Net-centricity enables substantially improved situational
    the service area. Additional resources can be made available at remote             awareness and shortened decision making cycles.
    sites to cope with overload situations. These characteristics inherently
    generate a natural contingency environment. As all services are                    Clarity concerning the term “Communication”
    available at all sites in the services area a failure on one site can be               The division into consumer, services and their physical location is
    automatically managed from other sites.                                            paramount for a service-oriented architecture and requires the accu-
                                                                                       rate use of the terms “Communication Services” and “Application
    The next table indicates the most important benefits.                              Services”.
                                                                                           Communication services represent the delivery mechanism. It is
     Benefits of Netcentric Operations                                                 similar to a water distribution system when PCM is the underlying
     >     Increased safety                                                            technology or a modern postal/parcel service when it comes to IP. The
     >     Increased flexibility in operations                                         only task which is to be expected from the communication service
     >     Increased operational capacity                                              is the delivery of information to distinct destinations with a certain
     >     Incremental commissioning                                                   quality and without affecting the information itself. The type of infor-
     >     Inherent contingency                                                        mation is basically irrelevant although it is reflected in the quality
     >     Increased efficiency                                                        of service required.


                                                                            Service Interfaces


                                          Client                                                                      Client

                                                                                                                    Robust and globally interconnected
                                                                                                                    Network Environment


                                                                   Client                        Client               Radio


      >figure 03_Service-Oriented Architecture requires Service Interfaces
MARKET & SERVICES                                                                                                                                                 7
>A paradigm shift boosts the quality of safety critical applications

    Consider that information that is represented by a stream of data,               Where does IP fit in?
like voice or video, has to be carried differently compared with infor-                  Netcentric operations based on a service-oriented infrastructure do
mation which is represented in fixed junks of data. These differences                not automatically imply a certain technology. Service orientation is a
are handled with quality of services mechanisms.                                     concept that affects the applications and the way they are designed and
    Applications on the other side provide services that generate,                   structured. It does not assume a certain communication technology. The
delete, manipulate, manage, retrieve, or store information; they                     only feature an application in a service-oriented implementation requi-
practically represent information. Applications develop a need to                    res is a delivery mechanism that guarantees a certain quality of service.
exchange information. This need is satisfied by the services a                           Frequentis has made the first steps towards netcentric operations with
communication system can offer. It is important to bear in mind that                 the development of the VCS3020XM application. This was the first appli-
the information that is exchanged between applications is not limited                cation that allowed any operator position in a networked infrastructure to
to user data. Information to co-ordinate and manage the applications                 access all radios and telephone lines. In supporting VCS3020XM for ATM-
themselves is required as well. For voice and video services, for                    type of communication backbones and for 2Mbit/s leased lines configura-
instance, this is known as signalling.                                               tions it becomes obvious that service orientation is independent from the
    In Netcentric Operations a common communication infrastructure                   communication technology and is not tied to an IP-infrastructure.
(“the famous cloud”) is present and a number of different consumers                      However, as more and more communication infrastructures use
and services are connected to this infrastructure at arbitrary points.               IP-technology as their transport mechanism it is evident that commu-
When separating Application Services and Communication Services it                   nication services provided with IP-technology will become the regular
becomes obvious that a new quality in interface definition is required.              case. But IP-technology brings along features that significantly facili-
Service interface definitions determine how Application Service                      tate the design of a service-oriented architecture because it allows
Entities exchange information. A Radio Service Interface for example                 to fully de-couple the application from the communications infra-
will describe the mechanism that allows a client application to retrieve             structure. This does not release the developer of the application from
a certain type of radio service. Furthermore, Service Interfaces will                considering the communication infrastructure but the characteristic
address issues of Service Management, Service Discovery and so on.                   to be respected is the available quality of service.



                          VCS               VCX                                                          VCX                VCS

                                          DATA                                                                   DATA





  >figure 04_Frequentis VCX Brings Existing Installations Closer to a Service-Oriented Architecture
    >A paradigm shift boosts the quality of safety critical applications




                                         VCS                                                                           VCS
                                         3020XM                                                                     3020XM

                                              DATA                                                               DATA





      >figure 05_The VCS 3020XM represents the First Frequentis Service-Oriented Architecture

    Frequentis represents                                                                The VCS 3020XM product allows using both ATM or PCM-techno-
    Netcentric Operations today                                                      logy as their communications infrastructure. The VCS 3020XM appli-
       Service-oriented concepts in Frequentis go back more than 10 years            cation will be able to run on an IP-backbone as well, provided
    when the networking concept for the Austrocontrol’s radio and phone              that this backbone offers sufficient quality serving safety-critical
    services has been developed. Based on components that add applica-               communication.
    tion service elements to an ATS-QSIG-based communications device                     Frequentis VCS 3020XM technology is a technological milestone
    existing VCS systems with no explicit service orientation capability             on the way to the Single European Sky. It is unique in its technological
    could be enabled to participate in a netcentric operations environ-              implementation and has potential to expand its capabilities into
    ment. The Frequentis VCX is today a successful product that enhances             future service-oriented environments.
    existing VCS systems with the capability to address any radio connec-                It has proven its maturity and benefits. Country-wide installations
    ted to the VCX network from any VCS.                                             in Switzerland, the United Kingdom and other non-disclosed defence
                                                                                     applications are operational for years and demonstrate the efficiency
    In 2001 Frequentis introduced the VCS 3020XM.                                    of net-centric operations in configurations comprising up to 20 facilities
       The VCS 3020XM is a product that for the first time allows inter-             that virtually work as a single installation. It provides the freedom to
    connecting single VCS systems in a way that results in a so-called               access all resources from any operator position in the system.
    “virtual centre”. This term indicates that there are no boundaries                   The Comsys initiative conducted as a study for the German Air
    between the VCS systems. All individual VCS 3020XM switches work                 Force is the latest and most far reaching development on the way to a
    as a virtual single centre where all resources – be it radio or                  service-oriented architecture that enables netcentric operations in an
    telephony – can be accessed from any position in a given configur-               IP-infrastructure. It makes use of the mechanisms and capabilities of
    ation. Furthermore, this infrastructure is managed by a single                   the IP-protocol and considers effects of WAN and LAN-characteristics
    management unit.                                                                 in the system design.
MARKET & SERVICES                                                                                                                                                            9
>A paradigm shift boosts the quality of safety critical applications

                                                                                                                                          “Home Land”


                                                                           Router                                                                           Router
                                                                                                           Radio Link System
                                                                     Crypto Box                                                                             Crypto Box

                        DISTRIBUTION                             Switch                                              Switch                                   Switch

                                                     …           …                …
                                                                     LAN                                      …      …                               …         …
                          Recording                                                                          LAN                                     LAN
                                                                                                                         Radio                                       Radio
                                                                                                  Radar                                Radar
                             Management                  Radio         Position
                                                                                                          Position                               Position

   >figure 06_The Comsys Initiative Aims for a fully IP-based Service Architecture for Voice and Other Services


                    Netcentric Operation is not a technology. It is a concept of operation and is thus closely connected to user interface issues and
                    operational processes. A service-oriented architecture is the technical concept that enables Netcentric Operations. The implementation
                    of a service-oriented architecture is independent of the communications technology, in particular IP-technology, but it requires a new
                    approach in thinking and designing of the application, which operates the information generated, required and used by a customer/user.

                    Both a netcentric operations concept and a service-oriented architecture can boost safety and efficiency of our customers and
                    introduce a new quality of capabilities.

                    Frequentis is mastering service oriented architectures on several different levels. Frequentis provides the VCX to upgrade existing
                    installations and the VCS 3020XM for new installations. In addition, with the COMSYS-initiative we prepare for the service
                    architecture of an IP-based future capable of utilizing IP-mechanisms.

                    Frequentis is the sole company to provide the novel operational concept of netcentric operations together with a broad set of
                    products and activities supporting this concept.

                                                                                                                                 Johannes Prinz, Wolfgang Kampichler
     >Expertise and Experience by the Frequentis User Interface Centre

     Humans in the Loop
                                                                                       In an increasingly competitive marketplace, those products and
                                                                                       services that do not meet customer needs fail. Ease of use is a
                                                                                       real user need and most product reviews, whether in consumer
                                                                                       magazines or professional journals, usually compare products
                                                                                       based on their usability. Research also shows that about 50 per-
                                                                                       cent of the code in new software applications is devoted to the
                                                                                       user interface, making it a significant cost component. Finally,
                                                                                       applications have become increasingly complex – and delivering
                                                                                       this increased complexity while maintaining ease of use is a
                                                                                       challenging endeavour.
                                                                                       The importance of usability will vary from product to product. For
                                                                                       safety-critical applications such as air-traffic control systems,
                                                                                       usability is crucial. Where a high value is placed on productivity,
                                                                                       or perhaps a high cost is associated with human error (such as
                                                                                       control centre rooms), usability is essential as well.

     [us·abil·i·ty]                                                                     When we deliver a highly usable system, we are delivering a higher
     “The extent to which a product can be used by specified users                   quality product because usability is one of the fundamental software
     to achieve specified goals with effectiveness, efficiency and satis-            quality attributes. Highly usable products entail happy users and user
     faction in a specified context of use.” (ISO 9241)                              organisations. Higher quality and satisfied customers together bring
        Usability is the measure of the quality of a user’s experience when          about numerous business benefits including a competitive edge and an
     interacting with a product or system – whether a software application,          improved bottom line.
     mobile technology, a website or any user-operated device. We at the                The quality of the user interface can make the difference between
     Frequentis User Interface Centre define usability as a combination of fac-      repeated business and a one-time affair. Developing usable applications
     tors that affect the user’s experience with the product or system, including:   for our clients is perceived as committment to total quality that
                                                                                     also includes usability aspects.
     1. Ease of learning.
        How fast can a user learn to accomplish basic tasks,                          Benefits for users of our systems
        if she has never seen the user interface before?                              > Ease of use
     2. Efficiency of use.                                                            > Higher productivity
        Once an experienced user has learned to use the system,                       > Reduced risk of human errors
        how fast can she accomplish tasks?                                            > Overall satisfaction
     3. Memorability.
        If a user has used the system before, can she remember enough                 Benefit for the product/project
        to use it effectively the next time or does the user have to                  > Reduced risk of late changes
        start over again learning everything anew?                                    > Reduced development and documentation cost
     4. Error frequency and severity.                                                 > Competitive advantages through safety-usable systems
        How often do users make errors while using the system, how serious            > Increased sales
        are these errors, and how do users recover from these errors?                 > Innovation due to user involvement
     5. Subjective satisfaction.                                                      > Satisfied customers
        How much does the user like using the system?
                                                                                      Benefits for our customers
        Thus usability is a term used to describe the quality of use of an            > Reduced cost while introducing and operating a new system
     interactive system. Usability answers questions such as: Does the                > Higher employee productivity
     system work correctly? Does the system offer a valuable service to the           > Improved operational efficiency
     user? Does the system fit the users’ need? Does the system help a                > Enhanced user acceptance
     company meet their business goals?
                                                                                        According to IBM, the rule of thumb in many usability-aware organiza-
     Why Usability? If users can’t use it, it doesn’t work!                          tions is that the cost-benefit ratio for usability of $1:$10-$100, i.e. for
        Usability directly impacts one of the most critical business                 every dollar spent implementing usability techniques, the organisation
     drivers: Quality.                                                               will realise a benefit between $10 and $100.
DEVELOPMENT                                                                                                                                                    11
>Expertise and Experience by the Frequentis User Interface Centre

Usability ok! But how?                                                             3. Develop an operational user interface specification for the system.
The Frequentis Usability Engineering Lifecycle                                     We base the system specification on our understanding of users’ needs,
    Usability engineering is a structured approach to building software            competitive analysis, and the resources needed to produce the system.
systems that meet the needs of users in various environments with varying          This specification is a measurable definition of usability that is shared
levels of computer experience. Our approach emphasises observation of              by all members of the project team.
people using software systems to learn what people want and need from
software systems.                                                                           These three development activities are sequential and may
    We at the Frequentis User Interface Centre believe that designers and         contain one ore more iterations if user requirements change. We do not
usability engineers must learn about the needs and preferences of actual          view user-interface design as a separate and initial part of the develop-
users and should build systems to accommodate them. With an understan-            ment process but as an ongoing process in system development.
ding of customer environments, an awareness of technological possibilities,
and creative imagination, we have produced many ideas for systems that             Summary
meet users’ needs.                                                                   Usability is defined in terms of users and what they need to be able
    In our Usability Engineering Lifecycle we define three principal activities    to do. This covers new users who require a high degree of guidance and
of software usability engineering:                                                 structure which may hide some of the power of a system from them, and
                                                                                   experienced users who require access to all of the functionality. The
 1. Know the user.                                                                 ultimate objective, however, is the same: a system must enable users to
 By understanding a customer’s current experience with a system, we                perform the tasks they need to undertake with effectiveness, efficiency
 gain insight into our opportunities to engineer new and better systems.           and satisfaction.
 We collect data on users’ experiences primarily through on-site visits              This user-oriented approach to system design of usability engineers
 using video observation and contextual interviews, that is, interviews            and user interface designers at the Frequentis User Interface Centre re-
 conducted while users perform their work.                                         quires a commitment to understanding and meeting users’ needs through
 2. Build early prototypes and involve users into the design process.              observation of people using systems, involving them into early design
 The first step in an evolutionary delivery process is building and testing        stages and tying it all together into a user interface design document.
 prototypes. These prototypes effectively test for ease of learning and              We believe that software usability engineering techniques, applied in
 can provide the germinal product. Prototyping also helps identify                 whole or in part, can produce computer systems that enrich human
 potential interface problems while still very early in the development            experience and thus significantly enhance overall product and service
 cycle.                                                                            quality making usability good business.

                                                                                                                                          Thomas Piribauer

     How to improve efficiency:
     Voice Recognition as an add-on for digital flight strips
     The task                                           handover, can be sent automatically at the       the read back matches the controller’s strip
         Air Traffic Controllers carry out              corresponding controllers action – e.g. by       data, values are transferred to the strip. It
     laborious tasks. They have to assure safe          putting the strip into the transfer bay.         takes one click to do this. Voice Recognition
     separation between all aircraft within             A text to speech algorithm sends these           is not classified to be a substitute for taking
     their area of responsibility. When we ana-         commands by means of voice.                      notes. It is seen as an aid to reduce the
     lyse the user’s tasks we see that there is                                                          amount of manual inputs. Our target is to
     one main redundancy: each spoken word              The solution                                     recognizes 80% of all possible phrases
     is written down additionally – or: each               The solution is voice recognition as an       with 95% accuracy. This would be sufficient
     control input has to be independently sent         add-on for digital flight strips. Presenting     for a drastic reduction of the controller’s
     to the pilot – by voice command. Therefore         clearances in the order spoken allows the        workload. This optimised accuracy is
     it is obvious where we can save workload:          controller to crosscheck pilot’s read back       possible through dynamic reduction of the
     by allowing the “system” to accept the             with his own “notes”. Values are displayed       active vocabulary. Interfaces to RDP and
     controllers voice – or better the content          immediately after being spoken out loud          FDP allow reducing the vocabulary to
     thereof – as direct input.                         and listed in a separate window attached to      match the situation in the sector.
         The other way round it works the same:         the referring strip. Accept or reject values.
     certain voice commands, e.g. at sector             Correct them or deselect them as desired. If                                      Theodor Zeh
     >VoIP solutions can provide benefits to ANSPs

     VoIP in ATC: Hope or Hype?
     Voice over Internet Protocol (VoIP), has
                                                                            Get IP Address                                     Register VoIP Device
     rapidly becoming a familiar term and
     technology that is invading enterprise,
     education and government organizations.
     VoIP is designed to replace the legacy TDM                             DHCP Server                                        Call Server
     technologies and networks with an
     IP-based data network. While the benefits
                                                          Phone                                                                                       Analog
     of a well-suited VoIP system are signi-
     ficant, selecting a VoIP solution for ATC                                                          IP LAN/WAN
                                                          Radio                                                                                       E1/T1
     can be a complex decision.
                                                                        Access/Media                                                 Trunk
                                                                        Gateway                                                      Gateway
         As a rule of thumb, organisations should
     approach it cautiously and implement only
     when they are absolutely certain that the
     technology will benefit them and provide the                                            IP Phone                  Soft Phone
     desired level of return. They also need to
     assess the readiness of their existing infra-       >Typical VoIP configuration
     structures. If the infrastructure is not capable
     of running VoIP, experiences could turn sour.
         As voice service is critical to ATC, Air       to IP addresses, enabling numbers to be              Beyond that, other frequently mentioned risks,
     Navigation Service Providers (ANSPs) can’t         reallocated to another location simply by re-        like eavesdropping and voice spam, are not
     afford to implement a technology that compro-      mapping the IP address. This means that VoIP         much more than hype. The VoIP Security
     mises call quality or reliability. In addition,    devices can be managed remotely – with most          Alliance (VoIPSA) recently introduced its
     they do not want to be so cautiously conserva-     changes taking just seconds to make – without        “Threat Taxonomy,” a reference document
     tive that they end up spending much more for       dispatching a technician to the site. This           listing the threats a VoIP system could face.
     the solutions than necessary. Why then move        feature of VoIP reduces the costs associated             The biggest risk is that someone would
     from a TDM-based telephone to an IP-based          with moves, adds, changes, and disconnects.          launch a denial-of-service attack, so one has to
     telephone? One or more of the following may            In traditional circuit-switched voice net-       have firewalls with stateful inspection capabi-
     justify the move to VoIP:                          works, the transport, call control and appli-        lities and intrusion prevention systems (IPS).
                                                        cation layers typically are grouped into single      Stateful firewalls do remember previous traffic
      >   Reduction of leased-line charges              proprietary systems. In IP networks, these           and can also investigate the application data
      >   Reduction of staff by combining voice         layers are represented by individual compo-          in a packet. Thus, stateful firewalls can handle
          network and data network management           nents that can be integrated or substituted as       application traffic that may not be destined
          and eliminating redundant functions           necessary to fit the needs of the overall system,    for a static port. But firewalls can degrade QoS
      >   Addition of expanded applications that        allowing the system, applications and services       in a VoIP system by introducing latency and
          are not offered by TDM-based systems          to be more dynamically designed and mana-            jitter.
      >   One common network for different              ged. Scalability and adaptability are seen as
          forms of communication                        one of the key benefits of VoIP solutions.           In summary, the VoIP hype is well founded.
      >   Greater operational flexibility               However, different systems scale and adapt              New VoIP solutions can provide benefits to
                                                        differently. As the character of ATC voice com-      ANSPs that select a solution that fits their
         The convergence of voice and data traffic      munication changes, ANSPs will need a VoIP           needs and successfully supports their
     onto a single network is eliminating infra-        solution to change and adapt with their needs.       operational requirements. One key success
     structure and maintenance redundancies                 Traditional telephony signalling made a lot      factor to a successful migration includes the
     while increasing network flexibility. IP tech-     of assumptions about the underlying network          right vendor partner to get the installation
     nology simplifies interoperability between         security. In an IP environment, you cannot only      right and to support you going forward. Your
     separate voice and data systems, providing the     rely on the network to handle security. Security     selected partner should understand LAN/WAN
     flexibility, extensibility and customisation       has to start “at home”, and with the client.         technologies and voice solutions, and must be
     needed while reducing operational costs.               Due to its default construction and deploy-      experienced supporting companies like yours.
         For instance, working positions or radio       ment, VoIP is susceptible to a number of easily
     site equipment have physical locations with        anticipated and defined attacks. Denial-of-                                   Wolfgang Kampichler
     for example regular extension numbers, but         service attacks against VoIP systems are still the
     these locations and numbers are then mapped        biggest security threat, according to experts.
RESEARCH                                                                                                                                                      13
>Enhanced Safety and Security

S2EV-Analog Voice with
enhanced Safety and Security
Introduction                                         pilots. The practically achievable improvement      VDL Modes 2, 3 and 4. It is based on two dif-
    It is hard to believe that at the beginning of   is reducing the threat of masquerading via          ferent underlying technologies, Data in Voice
the 21st century the Air Traffic Control (ATC)       message authentication.                             (DiV) and Aircraft Identification Tag (AIT) that
still uses analogue Very High Frequency (VHF)           Operational addressing within the current        can be operated in parallel without undesired
radio communications based on Dual Side              voice system is done verbally, by exchanging        mutual interference. Two distinct information
Band-Amplitude Modulated (DSB-AM) techno-            aircraft call signs and ATC-facility identifiers    containers can be hooked onto a voice
logy that was introduced many decades ago.           between air traffic controllers and pilots at the   message, one could be used for identification
Even more surprising, planned expansion of           beginning of the voice message. This is a           purposes, another one for the message
the 8.33 kHz system in Europe and freezing           potential safety risk, as aircraft call signs and   authentication.
the VDL Mode 3 deployment in USA indicate            ATC-facility names can easily be misunder-
that the DSB-AM system may survive for another       stood, which coluld at worst leed to the loss of     AIT and DiV technologies have some
decade or two even in very busy airspaces.           the prescribed aircraft separation. If verbal        common features:
    The DSB-AM radio system is completely            user identification were supplemented by a           > No changes of aircraft- or the ATC voice
open to masquerading (intruders pretend to be        digital exchange of users’ identifiers, the risk        radios are required
“real” air traffic controllers). In a scenario of    of misunderstanding or swapping call signs           > Modification (DSP patch) within the
ever increasing air traffic the overall safety       would be significantly reduced and the con-             baseband audio system is required at
level should also be improved. A question            troller’s situation awareness would increase.           both sides of the communications chain
arises: could the security and safety of the old        Improving security or safety of the existing      > PTT signal triggers time-limited
analogue voice system be improved at a               system generates a need to add limited “digital”        data transmission
reasonable cost?                                     features to the legacy analogue voice system.
    As an expert in aeronautical communi-            Such features should be implemented without
cations, Frequentis has developed so called          changing existing ATC voice radios or               Aircraft Identification Tag
Safety and Security Enhanced Voice (S2EV)            operational procedures.                             (AIT)
concept. It comprises two distinct technolo-                                                                 A prototype AIT system has been developed
gies: Data in Voice (DiV) and Aircraft               Possible Solution                                   in cooperation between Frequentis and EURO-
Identification Tag (AIT), providing two distinct        Frequentis Safety and Security Enhanced          CONTROL Experimental Centre Bretigny. AIT
information containers that are hooked onto          Voice (S2EV) concept is an enhancement of the       uses spread spectrum digital watermarking
each A/G voice message. These may become a           analogue voice communications system, it            technology.
vehicle for implementing security mechanisms         cannot provide the data link functionality              Using Linear Predictive Coding (LPC) analysis,
and improving system’s safety.                       and is therefore not comparable with                the spectrum of the voice signal is assessed

Safety and Security Threats
   Today, there is an increasing demand for
secure aeronautical communications. Large
progress has been achieved in other areas, but                             voice spectrum                        Watermark signal with adaptively varying
the voice radio system is today still completely                                                                 power is added to the voice signal over
                                                                                                                 entire voice bandwidth except for a part
open to physical jamming (external hostile                                                                       of the voice spectrum used by DiV
transmitter makes radio communications
unusable), masquerading (so called phantom
controllers and phantom pilots pretend to be
authorised system users) and message inter-
ception (eavesdropping on safety-related
voice traffic).
   The robustness of a narrowband DSB-AM
system against jamming cannot easily be
improved. Message encryption could provide
protection against masquerading and eaves-
                                                                              1 kHz                      2 kHz                           3 kHz
dropping, but may at the same time remove
the (very desirable-) party-line effect for the       >figure 01_AIT Principle
     >Enhanced Safety and Security

     once every 20 ms, the resulting voice estima-
     tes are used to modify the system parameters
                                                                                 ATC                          In-band modem DiV signal a notched-out
     when generating a watermark signal. The                                     voice spectrum               area around 2 KHz
     watermark information is spread over the ent-
     ire available audio bandwidth and adaptively
     masked by the audio signal so it cannot be
     recognised by a human ear (Figure 1). In order
     to remain orthogonal with the DiV system, the
     AIT system can be configured to exclude 300
     Hz of audio spectrum centred at 2 kHz.
         The signal-to-watermark power ratio is
     configurable between 12 and 28 dB. The level
     of the watermark signal dynamically follows
     the changes of the voice signal. The low-level
     spread-spectrum watermark signal can be
                                                                                   1 kHz                     2 kHz                      3 kHz
     detected even if its level is below the receiver
     noise floor. Matched-filters are used to syn-         >figure 02_DiV Principle
     chronise the receiver and exactly determine
     the position of the watermark within the set of      Data in Voice (DiV)
     samples. The synchronisation is achieved by             A prototype DiV system has been                (15 dB has been used in laboratory trials). DiV-
     using 18 bit Maximum Length Pseudo Random            developed by Frequentis. DiV uses the empirical   system introduces very low voice latency,
     Sequence (ML-PRS) at the beginning of the            fact that some parts of the voice spectrum can    received DiV-message can be presented to the
     message.                                             be removed without noticeable effect on the       user within one second after the transmitting
         In a typical configuration encoded data word     voice intelligibility. DiV implements an          party has activated the PTT-key.
     contains 12 user bits, 18 bits for synchronisation   in-band modem within the 300 Hz sub-band             Effective user’s payload is 128 bits of infor-
     and 50 bits for Forward Error Correction (FEC).      centred around 2 kHz (Figure 2). By this way it   mation with 240 bps raw signalling speed.
     User’s payload can be increased to 36 bits by        remains compatible with both 8.33 kHz and         24 bit CRC (Cyclic Redundancy Check) and
     changing the system’s configuration.                 25 kHz DSB-AM radios. The ratio of voice sig-     48 bits FEC (Forward Error Correction) ensure
                                                          nal to modem carrier power is configurable        data integrity.

                 PTT                                         Voice and S2EV
                event                                        data transmission

                                                                                                   Voice transmission without
                                                                                                   S2EV data transmission
                        td               1 sec

      >figure 03_Voice Event with S2EV Transmission
RESEARCH                                                                                                                                                    15
>Enhanced Safety and Security

S2EV Concept of Operation                           S2EV Architecture
                                                       S 2 EV concept requires no changes of            that is presented towards the local radio trans-
S EV data transmissions only occur when pilot       aircraft transceivers or ground ATC VHF-radios,     mitter along with a voice signal after a very
or controller activates the PTT key and are         only DSP-based S2EV end-systems (Figure 4)          short delay. The receiving S2EV end-system syn-
time-limited to 1 second.                           must be implemented within the airborne and         chronises to the transmitting S2EV end-system
    Controllers and pilots access the voice         the ground architecture. Specific S2EV HMIs         and extracts the data message from the compo-
channel “as usually”, by respecting the “listen     may be required in some cases to handle             site signal. Voice is forwarded to its recipient,
before PTT” rule. The data transmission starts      safety/security data and to display security        while the data message is demodulated, pro-
slightly delayed with respect to the PTT event      warnings.                                           cessed and presented on an external data HMI.
(Figure 3) to allow for the stabilisation of           Transmitting S2EV end-system – essential-            Within avionics, the S2EV end-system could
the radio path between the transmitter and          ly a DSP patch placed between the voice             be preferably integrated within the radio inter-
receiver. The transmitter remains keyed for         terminal and the VHF radio – accepts external       face of the Audio Management System (AMS).
one second even if the pilot or controller has      voice and buffers short data packets that           On the ground, the S2EV end-system may be
immediately released the PTT key. Having            arrive over separate interface. When the user       implemented in the VCS radio interface, within
completed the data transmission, the system         presses the PTT-key, the S2EV end-system            the Remote Control Equipment (RCE), optionally
reverts to the voice-only operation.                starts to produce the S2EV data message signal      also within the ground radio itself.

                                                                                     S 2EV Data


                                                  voice                                     voice
                                             S2EV Data
               Airborne                                          Airborne Audio                                            Pilot
               ATC Radio                               End       Management System

          voice &
          S2EV Data


                                           voice                                                    voice
                                         S2EV Data
               Ground                                                                                               S2EV   Air Traffic Controller
               ATC Radio                                   ATC Voice Communication System                            HMI

                                                                                S2EV Data

 >figure 04_S2EV Architecture
     >Enhanced Safety and Security

                                                                                                 secure voice
                                                                                                notification for
                                                                                               Controller’s voice

                                                                Authentication                                                  Pilot

             voice               Phantom

                                               secure voice

      >figure 05_Concept of Secure Voice

     S2EV Services
         Basic safety/security services provided by the S2EV system are
     talker identification and user authentication. The concept enables many
     other interesting services like digital annotation of the next sector
     frequency to the pilot or digital activation of the runway lighting.
         An aircraft transmits its digital Flight ID with each pilot’s voice
     message. The ground ATM system can easily validate received Flight IDs
     against flight plan and other available flight data. The airborne user that is
     currently active on the R/T channel can be indicated to the controller
     (Figure 5). No change of the current pilot’s procedures is required. The
     controller uses the Flight IDs provided by the S2EV system at his own
         The transmitting S2EV system (Figure 5) uses an appropriate
     key when encoding the S2EV message. The receiving system uses
     its own key to check the authenticity of received S2EV message. In order
     to preserve the party-line feature, an airborne S2EV receiver could be
     configured to accept/pass both “secure” and “non-secure” voice messages
     to the pilot. “Secure” messages from an authorized ground ATC facility
                                                                                      >figure 06_Indicating an A/C that is active on the radio channel
     could be accompanied by an additional visual/aural indication.

         The Safety and Security Enhanced Voice (S2EV) concept can be
     implemented within the existing ATC-voice communications system and is            Impressum
     based on two separate underlying technologies: digital watermarking               “Tech:News” is published in irregular intervals with current topics
     (AIT) and digital messaging (DiV).                                                through the Corporate Communications Center at Frequentis. Its
         Basic services provided are talker identification (enhancing safety) and      articles are principally based on projects and product information
     user authentication (adding security). Digital aircraft Flight ID (call sign)     concerning the companies of the Frequentis Group. “Tech:News”
     transmitted along with voice reduces the possibility of call sign misunder-       is distributed free of charge to customers, partners and friends of
                                                                                       the Frequentis Group.
     standing. Security problems due to “phantom controllers” and “phantom
     pilots” can be solved via user authentication.                                    FREQUENTIS GmbH
         As no changes of the airborne- or ground ATC-radios are required, the         Spittelbreitengasse 34_A-1120 Vienna_Tel: +43/1/81150-0
     S EV concept should be affordable to the widest aircraft population,              e-mail: marketing@frequentis.com_www.frequentis.com
     including the GA. As the analogue ATC-system may survive for another
                                                                                       Gestaltung & Illustrationen: [cdc] communicationdesignconsulting
     decade or two, Frequentis considers the S2EV concept as a vehicle to
                                                                                       Viriotgasse 4_A-1090 Wien_www.designconsult.com
     achieve the ambitious goal of improving safety and security of the aero-          Druck: Donau Forum Druck GesmbH
     nautical voice communications.

                                                                Miodrag Sajatovic

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