Communication Architecture in The Chosen Telematics Transport Systems
Communication Architecture in The Chosen Telematics Transport Systems
Communication Architecture in The Chosen Telematics Transport Systems
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The following chapter discusses data exchange architecture in transport telematic systems.
The issues concerning the structure and a means enabling information exchange between
different parts (elements) of transport telematic systems (means of data stream
transmission) were presented across four subsections.
The second part of the chapter delves into the very essence of transport telematic systems. The
concept of a transport telematic system is outlined and the transport telematics itself is situated
among other fields of knowledge and technologies. Information flows in telematic systems
were then analysed, concentrating with due diligence on transmission of telematics-based
information. Functions of transport telematic systems were defined, as a service intended for a
diverse range of target audiences directly or indirectly connected with transport processes of
people and/or goods. Delivering those services requires building data transmission networks
between entities using telematic systems to provide transport services
The third part of the chapter discusses the fundamental nature of communication
architecture as well as defines and determines the structure and a means enabling
information exchange between different parts (elements) of a system (means of data stream
transmission). Based on literature analysing data exchange in Intelligent Transport Systems,
such architecture was illustrated in an integrated urban traffic/public transport
management system. Another example of telematics-based data flow is data exchange
between highway management centres and highway telematic systems. Communication
architecture of highway telematic system was presented along with schematically depicted
data transmission in a highway management centre.
The subsequent section concerns the issues of building a teleinformatic infrastructure
enabling rail transport services. General architecture of rail infrastructure managers
telecommunications network was discussed, and services provided by that network
characterised. IT standards required to deliver integrated rail transport IT systems were
discussed as well. Wired and wireless communication networks were presented.
Teleinformatic services dedicated for rail transport were analysed.
The final part of the chapter discusses the issues of teleinformatic networks used in air
traffic management systems. Higher number of aircrafts within individual sectors, is only
acceptable should concurrently data transmission systems, informing about situation in
individual sectors of airways be improved. Basic issues related to migration of X.25
networks to networks using the IP protocol in their network layer were presented. The
concept includes the AFTN, OLDI and radar data transmission networks alike. One of the
most important surveillance data distribution systems ARTAS was also described.
Finally, presented was the possibility of deploying SAN networks characterised by
integrated architecture in order to enable exchange of construction data, planned and real
airspace restrictions.
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Said equipment and services are provided as telematics-based applications, i.e. purposebuilt tools. Example of such an isolated application is a road weather information system,
which informs users e.g. about crosswind.
Transport telematics marked its presence in Polish publications in mid-nineties. Already
back then, efforts were made to identify conceptual range and field of applications of
transport telematics (Wawrzyski W., 1997). Consequently it was defined as a field of
knowledge and technical activity integrating IT with telecommunications, intended to
address transport systems needs.
Transport telematics is a field of knowledge integrating IT and telecommunications,
intended for needs of organising, managing, routing and controlling traffic flows, which
stimulates technical and organisational activity enabling quality assurance of transit
services, higher efficiency and safety of those systems (Wawrzyski W., Siergiejczyk M. et
al., 2007)
Cooperating individual telematic solutions (often supervised by a superior factor e.g. an
operator supported by purpose-built applications), create Intelligent Transport Systems
(ITS). Convergence of telecommunications and IT, right through to Intelligent Transport
Systems has been presented schematically in figure 1.1.
Fig. 1.1. Transport telematics amongst related fields of knowledge and technology
The name Intelligent Transport Systems was accepted at the very first world congress held
in Paris, 1994, in spite of proposal made by International Organization for Standardization
of RTTT (Road Traffic and Transport Telematics). Regardless of the name, those systems create
architecture, designed to aid, supervise, control and manage transport processes and
interlock them. Transportation Management Systems, integrating all modes of transport and
all transit network elements within a given area, are also referred to as ATMS (Advanced
Traffic Management Systems) (Wydro K. B. ,2003).
Key functionalities of telematic systems are information handling functionalities. Namely its
collection, processing, distribution along with transmission, and its use in decision-making
processes. They are both the processes carried out in a pre-determined fashion (e.g.
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automatic traffic control) and incident-induced processes (decisions of dispatchers and realtime information supported, independent infrastructure users) (Klein L.A., 2001).
Telematics-enabled physical infrastructure called intelligent systems can vary in function
and dimensions. However, not only the range and number of elements constitute the size of
a telematic system. First and foremost the quantity and diversity of information fed through
and processed in the system matters, followed by the number of entire systems domains of
activity. In a broad sense, intelligent transport systems are highly integrated measuring
(detector, sensor), telecommunications, IT, information and also automatic solutions.
Intelligent transport integrates all kinds and modes of transport, infrastructure,
organisations, enterprises, as well as maintenance and management processes. Used
telematic solutions link those elements, enable their cooperation and interaction with
environment, users in particular. Telematic solutions can be dedicated for a specific type of
transport (e.g. road transport) and operate within a chosen geographic area (e.g. a local
administrative unit). They can also integrate and coordinate a continental or global transport
system.
Such solutions normally have an open architecture and are scalable: if required they can be
expanded, complemented and modernised. Their aim is to benefit users through interaction
with individual system elements assuring safer journeys and transit, higher transport
reliability, better use of infrastructure and better economic results plus to reduce
environmental degradation.
The fundamental feature of telematics-based applications is the capability to disseminate
and process vast amounts of information adequate to a given function, adapted to consumer
needs users of that information, specific for right place and time. Information can be
communicated either automatically or interactively, upon user request. An important
feature of telematics-based applications is their ability to effectively integrate different
subsystems and cause them to operate in a coordinated fashion.
2.2 Information transmission in transport telematic systems
One of crucial properties of telematic systems is broadcasting and transmitting information,
i.e. its flow. Distribution of telematic information is strictly linked to telecommunications, i.e.
transmission of information over a distance through different signals currently, often electric
and optic signals. Telecommunications services can provide multivariate data: alphanumeric
data, voice, sounds, motion or still pictures, writing characters and various measuring signals,
etc. The information chain is the salient aspect of telematic information distribution in terms of
telecommunications. In essence, the chain transmits multivariate messages from transmitter to
receiver, thus concentrates on two data exchange points. However, the fact the transmission
took place matters, as opposed to the way the information was transmitted. The way of
transmitting information matters in case of a communication chain, which is part of an
information chain. In case of a communication chain, important is data transmission from
transmitter to receiver without data identification. Important here is the message conversion to
transmittable signal and the transmission medium. During transmission, the signal is exposed
to interferences, thus often becomes distorted. Hence it is crucial, that the signal transmitted to
receiver is the best reproduction of original signal. The transmission medium is called
communication channel which is usually a wire (twin-lead, coaxial), optical fibre or radio
channel (Siergiejczyk M., 2009).
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Telematics-based systems interact with many other systems and environment, and can
encompass many constituent subsystems. Hence the aforementioned elements have to
interchange information (figure 2.1). In order to facilitate dataflow, required are different
types of transmission media, without which data distribution would not be possible.
Transmission media are used for both quick and reliable communication with widespread
systems, demanding tremendous amounts of data to be long-distance transmitted, and
short-distance transmission of basic control messages or measuring data from sensors.
Therefore, in case of systems on the table, transmission media and transmission mechanisms
play an important role.
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detail available for designing a service or other operation needed by a telematic system.
Other technical issues, such as data storage, storage location should not be ignored as well.
That solution can cause the need for a diversified way of data exchange, and consequently
e.g. different message display standards (Siergiejczyk M. ,2009).
The communication part of a telematic system, determines links between environments of
transport and telecommunications. Due to rapid development of telecommunications,
telematic systems designers have a wide selection of means at their disposal, enabling them
to accommodate needs induced by variable implementation circumstances. Communication
architecture does not hint though, on particular systems of technologies, instead merely
identifies technology-based capabilities. Four types of media were listed here, all suitable to
transmit information in transport telematic solutions. Those are the following
telecommunications systems (Wawrzyski W., Siergiejczyk M. et al., 2007):
It is worth pointing out, that there are numerous transmission techniques used for
communication between stationary points. E.g. proprietary or leased communication
channels can be used to operate traffic control subsystems. With intended other
applications, they can be microwaves, spread spectrum radio systems or local radio
networks.
Structure of physical architecture envisaged subsystems of the Control Centre (Management
and Supervision) connected with a wired network. It allows every subsystem to collect,
integrate and disseminate information to other subsystems in line with mutually accepted
communication and coordination rules, positively affecting operational effectiveness of those
subsystems. Depending on range and coverage, there are two types of wireless
communication. The first is long-range wireless communication, stipulating means used in
case of services and applications, where information is sent over long distances and regional
full coverage is required, providing constant network access. Further distinction concerns oneway and two-way communication, as it influences the choice of technology (e.g. radio
transmission is possible with one-way communication). Short-range wireless communication
is the second type, used to send information locally. There are two types, vehicle-to-vehicle
and DSRC (Dedicated Short Range Communications). The former is used i.a. for collision
avoidance systems, whereas DSRC for electronic toll collection, access authorisation etc.
Generally, it is fair to say that the analysis of traffic assignment and required data feed rates,
and the analysis of available transmission techniques lead to the conclusion, that commercially
available wired and wireless networks are capable of accommodating current and future
transmission needs in terms of telematics-based information.
3.2 Communication architecture in road transport
The KAREN (Keystone Architecture Required for European Networks) framework architecture
introduced by the European Union, implies support mechanism for information exchange
between different system elements. Such exchange should comply with the following:
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-
the mechanism should enable data transmission between relevant parties and be
sustainable in terms of cost, accuracy and transmission latency;
assure correctness of data transmission and interpretation.
Physical structure of a system i.e. elements identification, which i.a. exchanged data are
classified under Physical Architecture in KAREN. Identified were five main types of
elements and characterised were requirements concerning data exchange between such
elements (KAREN, 2000, Wawrzyski W., Siergiejczyk M. et al. ,2007, Wydro K. B., 2003):
Central the place which is used to collect, collate and store traffic data and to generate
traffic management measures, or fleet management instructions (e.g. Traffic Control
Centres, Traffic Information Centres or Freight and Fleet Management Centres);
Kiosk - a device usually located in a public place, providing traveller information (e.g.
tourist information, often self-service)
Roadside the place where detected are traffic, vehicles and pedestrians, tolls collected
and/or traffic management measures taken, and/or information are provided to
drivers and pedestrians;
Vehicle - a device that is capable of moving through the road network and carrying one
or more people (e.g. bicycles, motorcycles, cars, Public Transport Vehicles) and/or
goods (any form of road going freight carrying vehicle);
Traveller a person driving or using a vehicle.
Figure 3.1 illustrates example data exchange in an integrated traffic and road transport
management system. In order to describe data exchange, the following have to be
distinguished:
Systemic characteristics of data exchange processes requires dividing that area in two:
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Fig. 3.1. Data exchange in an integrated traffic and road transport management system
(Wydro K. B., 2003)
3.3 Communication structure of highway telematic systems
Another example of telematics-based data flow is data exchange between highway
management centres and highway telematic systems. Highway management centres are
centrepiece and the most important elements of highway telematics infrastructure
(Highway Management Center/ Traffic Management Center). A centre receives any data
from telematic systems located along a highway, and manages as well as operates those
systems. Using dedicated devices and software, variable message signs and cameras placed
along supervised section can be controlled. The centre can also process emergency calls and
have systems for collecting and analysing weather data. It also carries out functions of
comprehensive highway monitoring systems and provides information to users (drivers)
(Wawrzyski W., Siergiejczyk M. et al., 2007).
Among highway management centres functions are:
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traffic management;
weather and traffic conditions monitoring;
road surface monitoring;
emergency situations management (accidents) and emergency calls processing;
providing information to travellers both before and during the journey;
visual highway monitoring and adequate reactions;
maintenance services management.
An important aspect concerning highway management centre is its location. Centres are
located about every 60 km. The reasoning behind such practice is to assure maximum
distance of an accident from the nearest centre to be less than 30 km. Close proximity from
centres of maintenance and emergency services additionally further the case. Nevertheless,
in some cases big highway traffic monitoring and surveillance centres form, whose range
reaches up to several hundred kilometres. Also important is for the centre to be located in
heavily populated areas and on their periphery due to availability of highly qualified staff
and infrastructure elements.
Usually, the infrastructure of a modern highway management centre combines routers,
servers, LAN workstations, high resolutions screens with dedicated controllers and drivers,
peripheral devices and other network devices and an array of telecommunications
connections. Most crucial is the router, which is charged with receiving, transmitting and
routing packets in the network. Servers can support routers, and what is more, they are
equipped with high capacity hard disks enabling video recording. They also support local
network workstations and execute automated processes of telematic systems. Dedicated
servers are also used to process pictures captured by surveillance cameras, which replaced
thus far used analogue devices (multiplexers, video splitters). On centres walls hung are
high resolution screens, which display CCTV footage, feed from different applications,
maps showing position of highway patrol vehicles etc.
An important element of management centres architecture, are workstations performing
the function of a dispatch station operated by qualified staff. Powerful PCs equipped with
computer monitors and keyboards are used. A reliable operating system is also crucial.
Dedicated console or station built-in workstations are also often used. Using specialist
software, an operator can monitor and analyse data from weather stations and roadside
sensors. Moreover, thanks to the Internet current weather in the country can be previewed
the system automatically generates alerts and takes action, thus aiding human decisions.
Using the workstation, an operator can manage messages displayed on variable message
signs, RDS/DAB (Radio Data System/ Digital Audio Broadcast) system messages and operate a
parking guidance system. Chosen stations can process emergency calls from the highway
communication system without having to use dedicated dispatch stations. After the call is
answered, the number of column issuing the report is displayed on the computer screen.
The conversation is held by using headphones with microphone connected to a computer
and saved to the hard drive. The number of stations processing emergency calls should be
sufficient to assure instant connection with the dispatcher.
In order for the highway management centres to function efficiently, data transmission has
to be assured (figure 3.2). Communication with telematics-based highway systems is crucial
(emergency communication, traffic-related weather forecasts, video surveillance) as is data
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and customer (passenger) service. Examples are data centres, recovery data centres, and
virtual private networks dedicated for individual railway sectors or even applications (train
tracking, consignment tracking, online tickets booking etc.). Those services increase the
competitiveness of rail carriers and railway companies. The above-mentioned example
services could not be provided without an adequate telecommunications network (in this
case TCP/IP-compliant networks).
Building a telecommunications network is a process, which once started according to
experience has to be constantly continued. It is induced by several facts (Gago S.,
Siergiejczyk M. , 2006):
1.
2.
3.
4.
Due to those reasons, core telecom network designers have to accommodate the following:
Telecommunications,
Teleinformatic,
Telematics.
The role of communication devices is accurate data transmission over specified time from
transmitter to receiver. Both transmitter and receiver can be people, devices, different IT,
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2.
3.
4.
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telephone dispatch network assisting train control and management, almost exclusively
used by dispatchers,
teleconference phone network assisting operational company management.
The services provided by the aforementioned networks are still going to be useful and used
in transport and company management processes.
Data transmission networks
Railway companies operate generally nationwide. Their management is computer-aided.
Data required by those systems have to be collected nationwide also. In order to do that, a
data transmission network is needed. Quality_of_service of data transmission has to cater
for particular applications. Factors, taken into account in service quality evaluation are first
and foremost the BER (Bit Error Rate) and data transmission latency. Preferred currently are
TCP/IP-compliant convergent networks. Via that network, not only conventional data
transmission services can be provided but also other teleinformatic services, which were
created over the course of telecom, IT and media services convergence e.g. e-business, ecommerce, e-learning, CDN, SAN etc.
4.4 Wireless communication networks
Analogue radio communication
Wireless communication systems operating in 150 MHz band are currently used for railway
needs. That band, divided into adequate number of channels is used for a range of different
radio transmission technologies and applications, intended both for train control (train radio
communication) as well as managing individual applications in different railway sectors
(switch control radio communication, maintenance, Railroad Police etc.). Analogue
communication is technically and morally outdated and increasingly expensive (due to
channels in 25 kHz steps, however a change is planned to 12.5 kHz steps and in the
technology itself).
GSM-R digital cellular network system
Under Polish conditions, the GSM-R system is going to be the direct successor of the
aforementioned wireless communication system. The GSM-R system is a wireless
convergent network, which enables voice broadcast and data transmission services. Both
those services are commonly used in European railway companies, which have already
implemented those systems. The technology of deploying that system without having to
disrupt transport, requires introduction of additional, detailed temporary procedures. That
temporary period can take least a few years.
GSM-R networks are already operational worldwide, including European countries. In the
nearest future, the GSM-R is planned to be built in Poland as well. Currently used at Polish
Railways communication uses 150 MHz band which reached its maximum capacity, hence
does not meet todays technical requirements, norms and standards, and lacks the necessary
functionalities. The quality of connection is unsatisfactory. Major difficulties start to show
upon crossing the country border. Consequently, either the train radiotelephone or the
locomotive has to be replaced for one, which supports the type of communication used in
the given country. The UIC (French: Union Internationale des Chemins de fer), or International
Union of Railways envisaged predominantly the unification of European train
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communications systems by deploying the EIRENE project (European Integrated Railway radio
Enhanced Network) (UIC EIRENE FRS, 2006). Implementation of GSM-R translates into
tangible financial benefits for the railway industry. Railway line capacity improves
substantially, border crossing time shortens to minimum. Concurrently, the service quality
improves (e.g. by introducing consignment monitoring). There is a possibility to deploy
applications capable of: automatic barriers control at level crossings, direct video feed from
unattended railway crossings to the train driver, or voice messages communication over
platform speakers. By using those solutions, train traffic safety increases considerably.
Implementation of railway-dedicated mobile communication system will be the milestone
for Polish railway transport, allowing it at the same time to technologically catch up
Western Europe.
GSM-R is a digital cellular network system dedicated for railway transport. It provides
digital voice communications and digital data transmission. It offers expanded
functionalities of the GSM system. It is characterised by infrastructure located only in close
proximity to rail tracks. In order to counteract electromagnetic interference, the 900 MHz
frequency was used. GSM-R is intended to support deployed in Europe systems: ERTMS
(European Rail Traffic Management System) and ETCS (European Train Control System), which is
charged with permanent collection and transmission of rail vehicle-related data, such as
speed and geographic location. GSM-R as part of ETCS mediates in transmitting
information to the train driver and other rail services. By deploying the above-mentioned
systems, train traffic safety increases considerably, real-time vehicle diagnostics is possible
along with consignment and railroad car monitoring. Moreover, railway line capacity at
individual lines substantially increases due to accurate determination of distance between
trains (Bielicki Z., 2000).
Three fundamental types of cells are used in GSM-R systems. They were illustrated in figure
4.1 The first (1) are cells, which are assumed to cover only the railway line area. They are
characterised by elongated shape and small width. The second (2) are cells covering station
areas and partially railway lines. They are usually circular or elliptic. The third (3) are large
cells, covering railway areas such as sidetracks, railway building complexes etc. Every type
of cell supports all types of radiotelephones. Size and shape of cells can be altered by
adjusting telepowering or using omnidirectional antennas, either broadband or linear. The
GSM-R system is intended for railway applications only, thus the coverage does not exceed
railway areas.
Data transmission in GSM-R provides four fundamental groups of services: text messages,
main data transmission applications, automated faxes and train control applications. Text
messages can be distributed in two ways: point-to-point between two users or point-tomultipoint to many users simultaneously. Data transmission service concerns remote onboard and traction devices control, automatic train control, railway vehicle traffic
monitoring and passenger oriented applications. Passenger-oriented services can feature
schedule information, weather information, Internet access. Known from public solutions,
GPRS and EDGE packet transmission services were introduced to the GSM-R network.
GSM-R normative documents stipulate minimum data transmission rate of 2.4 kbit/s.
Moreover, railway communication network gives an option of implementing packet data
modes such as GPRS or EDGE. Those standards were discussed in the previous chapter. In
the GSM-R system, both the infrastructure and data transmission mode bear no difference to
those used in public cellular networks.
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functional addressing , where functional numbers are given to each user, by which they
are identified based on their function;
voice group call, point-to-multipoint, call set-up over a duplex connection,
high-priority calls, which are quickly set-up. Set-up time should not exceed one second.
The eMLPP (enhanced Multi-Level Precedence Pre-emption) mechanism prioritises the
calls;
position locating through transmitting short ID numbers of the base station, where the
train currently is;
emergency call. Those are calls of highest possible priority. They are made in case of an
emergency.
short message service known from public GSM networks have been deployed in
railway network to i.a. transmit encoded messages, imposing execution of different
actions related to railway vehicle control;
Direct Mode communication enabling communication without a fixed mobile system
infrastructure.
GSM-R can also handle diagnostic data transmission: data collection from measuring
instruments located in various parts of railway vehicle, collected data bundling and
transmission of collected diagnostic data over the GSM-R network to Maintenance Centre.
4.5 Teleinformatic services for railway transport
Teleinformatic and telematic services related to:
traffic control,
train control,
company management,
collaboration with carriers
Along with those services parameters should give guidelines for building
telecommunication networks catering for needs of companies operating in the railway
transport sector, both the physical layer i.e. optical fibre cables and the data link layer i.e.
transmission systems (e.g. SDH, Ethernet). As experience would suggest, there is currently
in every aspect - no better transmission medium than the optical fibre (broadband several
THz, low attenuation etc.). Solely on those grounds, an investor deciding to build a network
of optical fibre cable should use that medium to a maximum extent. Due to Railway
Company characteristic applications, broadly defined terminal devices are included in data
transmission process, thus protocols of network and transport layers of the aforementioned
ISO/OSI model (e.g. IP, TCP, UDP protocols) will be also used.
According to TSI requirements: the originator of any message will be responsible for the
correctness of the data content of the message at the time when the message is sent. (...) the
originator of the message must make the data quality assurance check from their own
resources (...) plus, where applicable, logic checks to assure the timeliness and continuity of
data and messages. Data are of high quality, if they are complete, accurate, error free,
accessible, timely, consistent with other sources and possess desired features i.e. are
relevant, comprehensive, of proper level of detail, easy-to-interpret etc.
The data quality is mainly characterised by:
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accuracy,
completeness,
consistency,
timeliness.
Accuracy
The information (data) required needs to be captured as economically as possible. This is
only feasible if the primary data, which plays a decisive role in the forwarding of a
consignment, a wagon or a container, is only recorded, if possible, on one single occasion for
the whole transport. Therefore the primary data should be introduced into the system as
close as possible to its source, e.g. on the basis of the consignment note drawn up when a
wagon or a consignment is tendered for carriage, so that it can be fully integrated into any
later processing operation.
Completeness
Before sending out messages the completeness and syntax must be checked using the
metadata. This also avoids unnecessary information traffic on the network.
All incoming messages must also be checked for completeness using the metadata.
Consistency
The owner of the data should be clearly identified. Business rules must be implemented in
order to guarantee consistency.
The type of implementation of these business rules depends on the complexity of the rule. In
case of complex rules which require data from various tables, validation procedures must be
implemented which check the consistency of the data version before interface data are
generated and the new data version becomes operational. It must be guaranteed that
transferred data are validated against the defined business rules.
Timeliness
The provision of information right in time is an important point. Every delayed data looses
importance. As far as the triggering for data storage or for message sending is event driven
directly from the IT system the timeliness is not a problem if the system is well designed
according to the needs of the business processes. But in most of the cases the initiation of
sending a message is done by an operator or at least is based on additional input from an
operator (e.g. an update of train or railroad car related data). To fulfil the timeliness
requirements the updating of the data must be done as soon as possible also to guarantee,
that the messages will have the actual data content when sending out automatically by the
system. According to TSI the response time for enquiries must be less than 5 minutes. All
data updates and exchange must be done as soon as possible. The system reaction and
transmission time for the update should be below 1 minute.
Currently almost all teleinformatic services have to be protected against:
data modification,
data destruction,
data interception.
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Due to its core activity, Infrastructure Manager has to prioritise data security issues. All data
concerning controlling, monitoring, and management of train traffic have to be protected at
each layer of the ISO/OSI model. Perhaps train control devices and systems are equipped
with autonomous security systems, nonetheless data transmission process has to be secured.
Other systems e.g. company management aiding systems should also be protected, because
they contain critical company data, e.g.:
financial data,
development plans,
pricing plans,
network topology,
Telecommunication services, which are and will soon be provided to the Infrastructure
Manager, can be listed as follows:
Data Centre various databases e.g. clients database, assets database, employee
database etc. Databases have to be systematically updated.
Recovery Data Centre recovery databases, which have to be synchronised with the
main database.
Content Delivery Network servers, databases containing information for:
clients,
employees,
business partners.
In those cases, data access through telephone is limited to relevant groups of interest.
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advertise through that portal. Their offers may concern e.g. supply of materials,
provision of services, prices, ads etc.
B2B e-commerce. This service allows buying, selling and payments online.
Contact Centre is a touchpoint, an interface of a service provider in this case PKP
PLK with the client. Currently, this service has strong growth dynamics worldwide.
E-learning a service useful in training staff, allowing to communicate e.g. rationale
behind boards or senior employees decisions.
Virtual Private Network virtual application-dedicated networks. This service
substantially increases application security, at least because of limited access (only
authorised users/entities can access the application).
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protocol, however, currently the network is based on either TCP or IP X.25. It resulted in
considerably higher data transmission capacity and reliability max capacity is currently
64 kbps. Both in Poland and most countries in the world, the standard is 9600 bps
completely sufficient at current network usage intensity.
The OLDI (On Line Data Interchange) system is responsible for communication between
neighbouring traffic control areas. Precisely speaking interconnected air traffic control
systems. It replaced voice information exchange concerning control hand-off over aircrafts
en route (EUROCONTROL/IANS, 2006). The system leans on exchanging i.a. ABI (Advanced
Boundary Information) teletype messages informing the ATC (Air Traffic Control) system
about an aircraft approaching the handover point.
Due to low data transmission error level, it could be used for connections characterised by
low technical parameters. The protocols drawback was its feature connectivity. Prior to
data transmission, connection between communicating devices had to be established by
using a dedicated connection.
Due to current development of local and wide area network infrastructure and used highreliability transmission media, Air Traffic Management (ATM) systems are being introduced
with datagram data transmission technologies. Wide area networks can be built as multicomponent structures thanks to the IP protocol. Those structures are built using different
technologies both standard and very unconventional. That flexibility is possible due to
developed network protocol stacks (TCP/IP), which is supported by the majority of
hardware and software platforms.
The above-mentioned actions cause the X.25 protocol to be withdrawn from many
aviation applications in favour of the IP protocol. Another powerful fact acting to
disadvantage of the X.25 protocol, is that manufacturers of hardware (X.25 switches)
supporting the protocol discontinued their sale and the technical support for X.25
solutions will have been unavailable by the end of the XXI centurys first decade
(EUROCONTROL/IANS, 2006).
Because aeronautical data transmission is inherent to ATM, the above-mentioned factors
affect considerably air traffic management systems (ATM). Thus, many key for ATM
systems will be subject to modification in the future, in a bid to adapt them to IP
data exchange technology. Among the systems, which first should undergo modification
are:
surveillance data distribution systems: ARTAS, RMCDE (Radar Message Conversion and
Distribution Equipment), ASTERIX-compatible radar stations (All Purpose Structured
Eurocontrol Surveillance Information Exchange),
aeronautical teletype message distribution and airport planning systems
existing: AFTN, CIDIN, WPPL,
implemented at PAP (Polish Air Navigation Services Agency): TRAFFIC (PANSA, 2008),
weather information distribution systems,
air traffic control systems: PEGASUS_21 (PANSA, 2009),
airspace management system: CAT (Common Airspace Tools) (PANSA, 2008),
aircraft charging system: CRCO.
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5.3 The concept of IP protocol migration and implementation into ATM systems
In 2001 at EUROCONTROL the IPAX working group was set-up to develop a plan of IP
protocol migration and implementation into ATM systems. It was charged with adapting
industrial standards of packet (IP) data transmission to data exchange standards in
ATM/CNS systems (Air Traffic Management / Communication Navigation Surveillance). IPAX
groups action plan included:
transition from X.25 network layers to IP with its integral security mechanisms,
modification of existing applications and systems so they would be compliant with
secure IP networks (developing interfaces of existing systems with IP networks),
maintaining application interfaces for operational users in order to protect investments
put into ATM systems.
One of the earliest modifications made in relation to X.25 protocol replacement with the IP
protocol, was the change implemented into the OLDI (On-Line Data Interchange) system. The
OLDI system has been operating using the X.25 protocol, which was implemented with a
higher layer protocol FDE (Flight Data Exchange). Due to X.25 layer replacement with the IP
layer, the higher layer protocol was also reimplemented. In order to adapt the OLDI system
to packet data transmission, the FDE protocol was replaced by the FMTP protocol (Flight
Message Transfer Protocol) (EUROCONTROL, 2008).
ANSP (Aeronautical Service Provider) centres across Europe are envisaged to ultimately be
introduced with that change. Its deployment overlaps with requirements stipulated by the
FDE/ICD (Flight Data Exchange/Interface Control Document) and it is the fundamental
requirement of the COM-04 objective contained by the ECIP (European Convergence and
Implementation Plan) document. During transition to FMTP, Eurocontrol will support FDEbased solutions (OLDI over X.25) until OLDI over TCP/IP is activated Europe-wide (see
figure 5.1.).
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change aims to migrate the X.25 technology used for establishing inter-centre backbone
connections to IP technology using AMHS (ATS Message Handling System) gateways. The
IPAX group set about deploying that solution in PEN (Pan European Network). The task
aims to build a global IP network supporting data exchange between air traffic management
systems.
The system intended to replace the AFTN/CIDIN network uses the X.400 protocol
implemented in IP networks. X.400 and AFTN network will be linked over the transition
period via gateways converting teletype messages format between protocols AMHS/AFTN GATEWAYS (Sadowski P., Siergiejczyk M., 2009). In figure 2.2 illustrates
AMHS/AFTN network architecture.
The AFTN protocol has many limitations. AFTN network adaptation to IP standards and
in higher layers to X.400 yields a range of benefits, amongst which are i.a.:
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TCP/IP protocols. ARTAS Units were implemented with the following functionalities
(EUROCONTROL/IANS, 2007):
tracker processes radar data and presents the most current, air traffic situation, based
on radar data reports,
server provides track and radar data to online users, and forwards radar data to the
tracker.
system manager administers the ARTAS system.
ARTAS connections require constant data stream transmission, hence PVCs (Permanent
Virtual Circuits) are used. Assuring continuity of data transmission is a significant issue.
Routing mechanisms ensure possibly low redundancy. System nodes are connected by
many alternative routes. In addition, every radar station has at least two connection
points with the core network. Communication is established through access networks,
which are independent for each node. Illustrated in figure 5.4 is the communication
architecture between ARTAS Unit modules ARTAS surveillance data distribution
system.
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SMTP NTP
MMS
management module
SRV
Radar Signal
server module
Users
RBD
router bridge module
LAN / WAN
TCP/IP
ARTAS Unit
TRK
tracker module
REC
movement register
module
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SSL, IPSec etc. mechanisms). FCIP protocol causes rapid development of wide area data
exchange and storage networks, increasing at the same time capabilities and efficiency of
built systems. Due to range of existing IP networks, FCIP enables building global data
storage systems. In figure 5.5 is presented SAN architecture of ARMS and TRAFFIC
systems.
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planned air operations. In dramatic cases they originate from technologically out-dated
teletype terminals and are fed to highly advanced AMHS systems.
6. Summary
An important issue facing transport in general is information exchange between supply
chain actors. Enabling that information to be transmitted, requires creating data
(information) exchange touch points (interfaces) and determining access privileges and
methods for different entities participating in transport processes.
The ever-expanding range of applications for telematic systems poses thus far difficult to
evaluate a potential, future risk to undisturbed functioning of transport telematic systems.
The telematics-induced networkisation and integration of computer systems present a
tangible and ever-increasing threat of both novel attacks taking advantage of network access
and deliberate damage to critical system elements. Further development of telematics
should take place in line with the "Fail-Safe" rule.
Systematic implementations of telematic technologies cause telematic systems to become a
viable consideration for development of multimodal transport. A potentially limiting factor
here can be the trend to use a single transport system in transport planning. However, one
of the biggest obstacles impeding further development of transport telematics is the
technology integration of different systems. This problem is driven by fast-paced innovation
and mostly inadequate standardisation.
Touch points of different systems have to be normalised, functions and services
standardised and costs analysed, all in a bid to allow such integration. It can stifle, however,
development prospects for transport telematics. The solution comes in form of a gradual
standardisation system, compatible at each stage. Benefits reaped from deployment of
transport telematic systems could not be quantified, until their impact and results are
recognised. Also, a line has to be drawn between telematics-related benefits for transport,
environment, economy and the society, hence providing reasons for detailed economic
analysis scrutinising implementation of transport telematic systems.
Providing telematic services supporting transport tasks and processes is one of fundamental
tasks of transport telematic systems. The quality of telematic services in transport depends
on network integrity, understood as the offered service being independent of the access
method and the communications protocol. Regardless of how information is transmitted to
the user, the service provided has to maintain constant parameters. Service quality of a
telematic service should remain the same at different locations. Thus, a need arises to create
and analyse functional-operating models in terms of availability and continuity of telematic
services in transport.
The other problem obstructing further development of transport telematics is the typically
long time of implementing the system. Deployment time often exceeds the total time needed
to develop a new technology. Hence, as practice shows, a system might become
technologically outdated by the time it is mature enough for practical applications. Effective
technologies, however, should not be replaced by newer solutions if telematics was to
develop. Many sectors manage to continue using obsolete, but proven technologies to their
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advantage, because a transition to new technologies would be too financially strenuous (e.g.
flight and railway security).
7. References
Bielicki Z. (2000). Pan-European Communications. New signals no. 4. KOW, ISSN 1732-8101
Warsaw, Poland
EUROCONTROL (2008). Eurocontrol guidelines for implementation support (EGIS) Part 5
Communication & Navigation Specifications Chapter 13 Flight Message Transfer
Protocol (FMTP). Eurocontrol, Belgium
EUROCONTROL/IANS (2006). Training activities COM-DATA. Eurocontrol Luxemburg.
EUROCONTROL/IANS (2007). Training activities: ARTAS, Eurocontrol Luxemburg
European Parliament and Council (2001). Directive 2001/16/EC of the 19 March 2001 on the
interoperability of the trans-European conventional rail system.
Gago S., Siergiejczyk M. (2006). Service convergence in railway-dedicated IP networks.
Telecommunications and IT for Railway. Polish Chamber of Products and
Services for Railway (CD), January 2006, Szczyrk, Poland
Janikowski A. (2002). Fibre Channels outlined. NetWorld no. 3. IDG PH, ISSN 1232-8723,
Warsaw, Poland
KAREN (2000). Foundation for Transport Telematics deployment in the 21st Century.
Framework Architecture for ITS. European Commission Telematics Applications
Programme (DGXIII/C6). Brussels.
Klein L.A. (2001). Sensor Technologies and date requirements for ITS. Publisher Artech
House ITS Library, ISBN 1-58053- 077-X, Boston, USA, London, England
Ochociski K. (2006). Technical Specifications for Interoperability for Telematic Applications
for Freight (TSI TAF). SIRTS and CNTK seminar, 07.2006, Warsaw, Poland
PANSA (2008). System TRAFFIC. Functional and Technological Specifications (FTS),
Warsaw, Poland
PANSA (2009). Materials provided by the Polish Air Navigation Services Agency. Warsaw,
Poland
Pogrzebski, H. (2005). Functions of the TAF-TSI specification planning procedure and train
preparation. TTS Rail Transport Technology. R. 11, no. 11. EMI-PRESS, ISSN: 12323829, Lodz, Poland
Sadowski P., Siergiejczyk M. (2009). IP networks for air traffic management systems.
Telecommunication Review and Telecommunication News no. 8-9. ISSN 1230-3496.
Sigma NOT PH, Warsaw, Poland
Siemens (2001). GSM-R Wireless Communication. New Signals no. 29, KOW, ISSN 17328101, Warsaw, Poland
Siergiejczyk M. (2009). Exploitation Effectiveness of Transport Systems Telematics. Scientific
Works of Warsaw University of Technology. Transport Series. Issue No. 67.
Publisher: OW PW. ISSN 1230-9265, Warsaw, Poland
Siergiejczyk M., Gago S. (2008). Teleinformatic platform for data transmission in cargo
transport. Logistics no. 4. Publisher: Institute of Logistics and Warehousing , ISSN
1231-5478, Poznan, Poland
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ISBN 978-953-51-0647-0
Hard cover, 166 pages
Publisher InTech
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