SIST-TS CEN/TS 14821-7:2003
(Main)Traffic and Travel Information (TTI) - TTI messages via cellular networks - Part 7: Performance requirements for onboard positioning
Traffic and Travel Information (TTI) - TTI messages via cellular networks - Part 7: Performance requirements for onboard positioning
This CEN/TS defines the specific interfaces and functionality of traffic telematics (TT) services based on the use of cellular networks. Device manufacturers are enabled to develop terminal equipment compatible to services based on this CEN/TS. This will allow for interoperability of different terminal equipment and service providers which allows competition between service providers and terminal manufacturers. Furthermore it sets the scene for international availability of these services.
This CEN/TS specifies
• TT-specific interfaces between terminal and service centre. This especially incorporates the message sets of the application data protocols and the service-independent communication handling (including conditional access and transport protocols).
• Functionality, procedures and requirements of basic terminal components as well as their interaction with the service centre. This especially comprises conditional access and security mechanisms.
• Service Specifications, which are essential to ensure consistent behaviour of terminal and service centre.
The services incorporated within this issue comprise:
• breakdown and emergency services
• interactive traffic information services
• broadcast traffic information services
• navigation services (route assistance, route advice, homing)
• operator services
• general information services
• floating car data collection
It is envisaged that future research and development will lead to improvements on the services listed above as well as to the creation of new services. Nevertheless this CEN/TS provides the framework for seamless integration of new features and services into the existing architecture.
Verkehrs- und Reiseinformationen (TTI)-TTI-Nachrichten über mobile Netzwerke - Teil 7: Leistungsanforderungen für fahrzeuggebundene Positionsbestimmung
Prometne in potovalne informacije (TTI) - Sporočila TTI prek celičnih omrežij – 7. del: Zmogljivostne zahteve za pozicioniranje z vgrajeno opremo
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TS CEN/TS 14821-7:2003
01-oktober-2003
3URPHWQHLQSRWRYDOQHLQIRUPDFLMH 77, 6SRURþLOD77,SUHNFHOLþQLKRPUHåLM±
GHO =PRJOMLYRVWQH]DKWHYH]DSR]LFLRQLUDQMH]YJUDMHQRRSUHPR
Traffic and Travel Information (TTI) - TTI messages via cellular networks - Part 7:
Performance requirements for onboard positioning
Verkehrs- und Reiseinformationen (TTI)-TTI-Nachrichten über mobile Netzwerke - Teil 7:
Leistungsanforderungen für fahrzeuggebundene Positionsbestimmung
Ta slovenski standard je istoveten z: CEN/TS 14821-7:2003
ICS:
35.240.60 Uporabniške rešitve IT v IT applications in transport
transportu in trgovini and trade
SIST-TS CEN/TS 14821-7:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TS CEN/TS 14821-7:2003
TECHNICAL SPECIFICATION
CEN/TS 14821-7
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
May 2003
ICS 35.240.60
English version
Traffic and Travel Information (TTI) - TTI messages via cellular
networks - Part 7: Performance requirements for onboard
positioning
This Technical Specification (CEN/TS) was approved by CEN on 10 May 2001 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available. It
is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible
conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 14821-7:2003 E
worldwide for CEN national Members.
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Table of contents
PAGE
TABLE OF CONTENTS 2
FOREWORD 3
INTRODUCTION 4
1. SCOPE 5
2. NORMATIVE REFERENCES 6
3. DEFINITIONS AND ABBREVIATIONS 6
3.1 Definitions 6
3.2 Abbreviations 9
4. MINIMUM ONBOARD POSITIONING PERFORMANCE REQUIREMENTS FOR TRAFFIC
TELEMATICS TERMINAL DEVICES 14
4.1 Introduction 14
4.2 Required Positioning Performance 14
4.3 Diagnostics Interface 19
4.4 Quality Verification Method 20
5. PREPARATION OF EXTENDED LOCATION 22
5.1 Introduction 22
5.2 Requirements / References 22
5.3 Incoming data 22
5.4 Outgoing data 23
5.5 Generating a chain of elements 23
ANNEX A. (INFORMATIVE) EXAMPLES 29
BIBLIOGRAPHY 32
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Foreword
This document (CEN/TS 14821-7:2003) has been prepared by Technical Committee CEN/TC 278" Road
transport and traffic telematics ", the secretariat of which is held by NEN, in collaboration with Technical
Committee ISO/TC 204 " Transport information and control systems ".
This CEN/TS was prepared by Working Group 7 of CEN TC278. In the field of Traffic and Traveller
Information, the innovative rate is high, with many research and development projects under way in many
countries, and there is a need to establish prospective standards which allow manufacturers to introduce
competitive products to the market in the knowledge that they can accommodate the future issues of the
standard(s) without fundamental change to equipment.
No known national technical specificationss (identical or conflicting) exist on this subject.
CEN/TS 14821 consists of eight parts; one part describing the framework and seven parts providing detailed
specifications of all components, protocols and services that are within the scope of CEN/TS 14821.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Specification: Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
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Introduction
Traffic and Traveller Information (TTI) may be disseminated through a number of services or means of
communication, covering static displays, portable terminals and in-vehicle equipment.
For all such services, the data to be disseminated, and the message structure involved in the various
interfaces, require clear definition and standards formats in order to allow competitive products to operate
with any received data.
This CEN/TS focuses on an application data specification whereby data is produced at a central location and
is disseminated via a cellular radio network. It addresses the data specifications for both downlink and uplink
existing between a central location and randomly located vehicles. It enables messages to be exchanged
between different systems and service providers adopting a variety of applications specifications.
Other technical specifications are being produced by the CEN TC278 Working Group 4 to cover TTI
dissemination via other means or services. This set of specifications is named GATS (Global Automotive
Telematics Standard). GATS provides the modular framework for implementing such traffic telematics
services on an open technology platform and is network - independent. In many details definitions are
necessary to ensure interoperability. Therefore, those detailed definitions are given in a network-specific part
(CEN/TS 14821-8). With the development of future mobile communication systems towards UMTS / IMT2000
the bottleneck of narrow-band data communication might fade. Due to its modular structure, the GATS
framework and applications are prepared for that due to its network-independence. The same holds for
emerging technologies for positioning which today is almost exclusively based on GPS.
Other relevant standard developments are, independent from telematics, the application-independent
Wireless Application Protocol (WAP), enabling mobile access to the Internet. It is understood that these
emerging technologies might fit into the framework of telematics applications in future WAP-versions. For the
time being, GATS already today independently from WAP enables access to telematics services. Utilisation
of GATS on a WAP protocol stack and identifying necessary adaptation of WAP specifications (if any) is
currently under investigation of the appropriate groups within WAP-Forum and GATS-Forum.
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1. Scope
This CEN/TS defines the specific interfaces and functionality of traffic telematics (TT) services based on the
use of cellular networks. Device manufacturers are enabled to develop terminal equipment compatible to
services based on this CEN/TS. This will allow for interoperability of different terminal equipment and service
providers which allows competition between service providers and terminal manufacturers. Furthermore it
sets the scene for international availability of these services.
This CEN/TS specifies
• TT-specific interfaces between terminal and service centre. This especially incorporates the message
sets of the application data protocols and the service-independent communication handling (including
conditional access and transport protocols).
• Functionality, procedures and requirements of basic terminal components as well as their interaction with
the service centre. This especially comprises conditional access and security mechanisms.
• Service Specifications, which are essential to ensure consistent behaviour of terminal and service centre.
The services incorporated within this issue comprise:
• breakdown and emergency services
• interactive traffic information services
• broadcast traffic information services
• navigation services (route assistance, route advice, homing)
• operator services
• general information services
• floating car data collection
It is envisaged that future research and development will lead to improvements on the services listed above
as well as to the creation of new services. Nevertheless this CEN/TS provides the framework for seamless
integration of new features and services into the existing architecture.
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2. Normative references
Not applicable
3. Definitions and abbreviations
3.1 Definitions
For the purpose of this CEN/TS, the following definitions apply:
3.1.1 Accuracy
The ability of the positioning module to maintain the value of a specified parameter within an error limit with a
specified probability.
3.1.2 Attribute (of a Traffic Information Message)
A Traffic Information Message is made up of separate parts that can be called attributes. This includes, for
example, an item of information and a length of validity.
3.1.3 Authorisation
Reciprocal proof that the identity provided by the communications partner is valid
3.1.4 Availability
The ability of the total system to provide the required guidance at the initiation of the intended operation. It is
evaluated by determining the probability that the system starts up providing the required positioning
information at the initiation of each test ride.
3.1.5 Broadcast Service
Data service within a cellular wireless network that allows for mono-directional dissemination of data from a
service centre to multiple users in the area of signal reception
3.1.6 Bypass Description
Representation of a Bypass, consisting of a Bypass Hint and/or a Bypass Route.
3.1.7 Bypass Hint
Representation of a hint for a Bypass
3.1.8 Bypass Link
Prominent waypoints on a Bypass Route
3.1.9 Bypass Route
Representation of the route for a Bypass
3.1.10 Cell Broadcast
Broadcast service of the GSM network
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3.1.11 Continuity
The ability of the total system to perform its function with the required performance without interruption during
the intended operation. It is evaluated by determining the probability that the system provides the required
positioning information without interruption during the duration of each test ride.
3.1.12 Coverage
Relates to the physical boundaries within which the positioning module must be able to provide its information
with the required performance.
3.1.13 Data telegram
Digital message exchanged between two systems
3.1.14 Delivery Notification
Network acknowledgement for successful/ unsuccessful delivery of a message to the mobile device
3.1.15 Functional Road Class
A classification based on the importance of the road element in the connectivity of the total road network
3.1.16 Functional Road Class 0
Motorways
3.1.17 Functional Road Class 1
All non-Motorways that are part of a connection used for nation wide traffic and transport
3.1.18 Geocode
Geocodes are unique identifiers unmistakably defining important points on road networks. Geocodes can be
derived from / converted into WGS84 co-ordinates by the algorithm described in CEN/TS 14821-3.
3.1.19 Hardware service agents
Partner companies of the traffic telematics service providers who are authorised to install onboard equipment
into vehicles and to maintain it
3.1.20 Homing
Simple form of guidance to destination, in which the direction and
straight-line distance of the destination are indicated
3.1.21 Information Element
Information unit of a message
3.1.22 Integrity
The quality which relates to the trust which can be placed in the correctness of the information supplied by
the positioning module. It is specified in terms of the probability that the required performance parameters are
not degraded by an undetected failure. Therefore, integrity includes the provision of an error estimation for
specific parameters. The estimated errors must be maintained within certain limits with specified probabilities
(Probability of Missed Detection, PMD; Probability of False Alarm, PFA). Integrity also includes the provision
of a warning that the system should not be used for the intended operation in case specified error limits are
exceeded.
3.1.23 Intersection
Junction of two or more roads
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3.1.24 Latency
The period of time since application of power until position information with a specified accuracy can be made
available in the terminal device for traffic telematics service initialisation and/or use.
3.1.25 Length of a Speech Report
Length of a Speech Report, including pauses, in tenths of a second
3.1.26 Mobile Originated
Data telegram sent from the onboard equipment to the Service Centre.
3.1.27 Mobile Terminated
Data telegram sent by the Service Centre to the onboard equipment.
3.1.28 Onboard equipment
A system, generally mobile, interacting with the service centre to handle traffic telematics services
3.1.29 Road Junction
Intersection of two or more roads
3.1.30 Route description
Description of a route showing the geometry of street intersections, manoeuvre instructions, street and place
names, and geographical co-ordinates
3.1.31 Service centre
System produced by the traffic telematics operators / service providers to handle traffic telematics services
3.1.32 Short Message Service
Packet-based form of data transfer within the GSM network
3.1.33 Speech connection
Communications channel between two systems for the bi-directional transmission of speech
3.1.34 Speech Report
Traffic Information Report transmitted by a speech system
3.1.35 Terminal Device
Generally mobile system interacting with the service centre for implementation of telematics services
3.1.36 TINFO
Traffic Information Report
3.1.37 TINFO Version
Unique identification of a Traffic Message, consisting of a number and a time stamp
3.1.38 Traffic Data
Data for qualification of Traffic Events. This includes:
Values: speed, traffic flow, traffic density
Places: position, place designation
Facts: description of situation
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3.1.39 Traffic Event
An occurrence on a road or in an area that is worthy of reporting, such as a traffic jam, wrong-way driver, or
fog.
3.1.40 Traffic Information
Technical representation of a Traffic Situation within the onboard equipment, accomplished by a number of
Traffic Information Reports.
This Traffic Information can be displayed to the customer via suitable terminals.
3.1.41 Traffic Information Report
Technical representation of a Traffic Event produced by processing traffic data.
Each Traffic Reports uniquely identified by a number, the TINFO ID, a time stamp, the TINFO version.
Note: If the Traffic Event changes, the time stamp changes, but the TINFO ID number does not.
3.1.42 Traffic Situation
The total number of all Traffic Events taking place that deserve reporting within an area. The Traffic Situation
is always linked to an area. Thus, for example, an areas could be a conurbation or a geometrically
demarcated area; an example is the radius around a point.
3.1.43 Voice connection
Circuit-switched channel between two systems for bi-directional voice transmission
3.1.44 Waypoint
Significant points on the route
3.2 Abbreviations
For the purpose of this CEN/TS, the following abbreviations apply:
3.2.1 % ott
percent of the time
3.2.2 ADP
Application Data Protocol, i.e. a message set for a telematics service
3.2.3 AM
Acknowledge Message
3.2.4 ASN.1
Abstract Syntax Notation
3.2.5 BC
Broadcast
3.2.6 BCS
Broadcast Service
3.2.7 CA
Conditional Access
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3.2.8 CAS
Conditional Access and Security
3.2.9 CB
Cellular Broadcast
3.2.10 CBC
Cipher Block Chaining
3.2.11 CLI
Calling Line Identification
3.2.12 CRM
Calling Request Message
3.2.13 CSD
Circuit Switched Data
3.2.14 DES
Data Encryption Standard: symmetrical encryption procedure
3.2.15 DRM
Digital Road Map
3.2.16 DSC
Data Service Centre: depending on the mobile communication network
3.2.17 ELB
Extended Location Block
3.2.18 FCD
Floating Car Data
3.2.19 FCDGM
FCD General Message
3.2.20 FCDPM
FCD Parameter Message
3.2.21 FCDNSM
FCD Notification Set-up Message
3.2.22 FCDRM
FCD Revoke Message
3.2.23 FCDVDSUM
FCD Virtual Detection Site Update Message
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3.2.24 GATS
Global Automotive Telematics Standard
3.2.25 GEM
General Error Message
3.2.26 GPS
Global Positioning System NAVSTAR GPS
3.2.27 GSM
Global System for Mobile Communication
3.2.28 IE
Information Element
3.2.29 ICV
Initial Chaining Value
3.2.30 L_max
Max. length of transferable data in one data transaction
3.2.31 MAC
Message Authentication Code
3.2.32 MNA
Mobile Network Address
3.2.33 MF
Mandatory Fixed format
3.2.34 MO
Mobile Originated Message
3.2.35 MT
Mobile Terminated Message
3.2.36 MV
Mandatory Variable format
3.2.37 N_min
Minimum number of ELB waypoints
3.2.38 OBU
Onboard Unit, synonymously used telematics device, telematics terminal
3.2.39 OF
Optional Fixed format
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3.2.40 OV
Optional Variable format
3.2.41 PDU
Protocol Data Unit
3.2.42 PFA
Probability of false alarm (i.e. estimated error is too large)
3.2.43 PMD
Probability of missed detection (i.e. estimated error is too small)
3.2.44 RSA
Asymmetrical encryption procedure by Rivest, Shamir and Adleman
3.2.45 SAE
Society of Automotive Engineers, Inc.
3.2.46 SMS
Short Message Service
3.2.47 SMSC
SMS Centre
3.2.48 SV
Space Vehicle
3.2.49 TEG
Telematics Expert Group – Group within the WAP-Forum Ltd.
3.2.50 TINFO
Traffic Information Report
3.2.51 TOC
Telematics Operator Code
3.2.52 TRP
Transport Protocol
3.2.53 TT
Traffic telematics
3.2.54 TTI
Traffic and Traveller Information
3.2.55 TTFF
Time to First Fix
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3.2.56 UTC
Universal Time Co-ordinated
3.2.57 VDS
Virtual Detection Site
3.2.58 vel, V
Velocity
3.2.59 VIN
Vehicle Identification Number
3.2.60 WAP
Wireless Application Protocol
3.2.61 WGS84
World Geodetic System 84
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4. Minimum Onboard Positioning Performance Requirements for
Traffic Telematics Terminal Devices
4.1 Introduction
The development and implementation of telematics services such as navigation services or emergency and
breakdown management make it necessary to develop standardised requirements for the positioning
components of road vehicle terminal devices.
This document contains performance requirements for the positioning modules of the first generation of
onboard traffic telematics terminal devices. These requirements are based on one hand on the quality
requirements for the different traffic telematics services and on the other hand on the need to implement
simple and cost effective solutions suitable for automotive applications.
According to the Global Automotive Telematics Standard (GATS) several telematics services are offered to
customers of the private, public and commercial transport sectors. These services comprise
• security services,
• navigation services,
• traffic information,
• general information services and
• traffic situation determination.
These applications impose differing requirements on the performance of the positioning components of
telematic onboard units. This document describes the requirements for such components in terms of
• coverage,
• latency,
• accuracy,
• availability,
• continuity and
• integrity.
The performance requirements set out in the following section are based on miscellaneous standards and
surveys as well as experimental results obtained utilising state of the art technology. They differ according to
the needs imposed by the different services. Their fulfilment is mandatory, however the application of specific
technologies is not prescribed and left at the discretion of the equipment manufacturers.
4.2 Required Positioning Performance
According to the European Radionavigation Plan (ERNP) "navigation" can be defined as "the safe and
expeditious conduct of a craft from departure to destination". Therefore a system defined as "navigation aid"
is considered to be necessary for the safety of the craft using it and capable of providing the navigational
information in real-time. Other applications where for example the location of a vehicle has not to be
determined in real-time or on the vehicle itself, nor would a malfunction directly endanger it, are described
with the terms "location" and "positioning". All road vehicle applications referred to in this document fall into
this category.
In order to enable a flawless provision of traffic telematics services the positioning modules of terminal
devices must fulfil the requirements set out in this document. Generally, these requirements are defined using
the definitions given in this CEN/TS and are closely related to the verification method described in 4.4:
It is obvious that for a successful implementation of the services mentioned above all requirements must be
met simultaneously.
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4.2.1 Coverage Requirements
The positioning components of traffic telematics units must fulfil the requirements mentioned in the following
sections within the physical boundaries specified below (minimum requirements):
• geographical coverage: Europe
• dynamic coverage: - velocity: 0 - 250 km/h
2
- acceleration: 0 - 1g (1g = 9.80665 m/s )
n n
- yaw rate: 0 - 60°/s.
4.2.2 Latency Requirements
4.2.2.1 Cold Start
The cold start behaviour is defined by the time to first fix (TTFF) of position with the required accuracy after
the device is switched on
• upon commissioning,
• following prolonged downtimes (days/weeks or longer),
• following separation of the terminal device from its power supply (main & backup), or
• following relocation over long distances without activation of the positioning module.
The cold start TTFF should not be longer than 240 seconds during vehicle motion and with clear view of the
sky.
4.2.2.2 Warm Start
The warm start behaviour is characterised by the time until the position information stored in the unit's
memory before the system was last switched off is made available for service initialisation as well as by the
time to first fix (TTFF) of new position information with the required accuracy after the device is switched on
in all situations not covered by 4.2.2.1.
The time until stored position information is available should not be longer than 5 seconds.
The warm start TTFF should not be longer than 30 seconds during vehicle motion and with clear view of the
sky.
4.2.3 Requirements for Positioning Performance Parameters
4.2.3.1 Security Services
Security Services comprise breakdown, call for help and emergency services (see CEN/TS 14821-6). Due to
their nature, security services impose stringent requirements on the positioning modules of traffic telematics
terminal devices. Accuracy and continuity are key parameters to assure the functionality of the service, since
in these cases it is necessary to locate a damaged vehicle with a high probability even in adverse conditions
as e.g. in urban canyons, forests, tunnels, etc. Obviously, emergency management is here the more critical
case. To locate a vehicle that has issued an emergency or breakdown call the onboard unit transmits a mes-
sage to the service centre that contains information about the vehicle's actual position. The format of this
message is specified in CEN/TS 14821-3. It basically consists of a chain of waypoints the vehicle has passed
along its last few kilometres. At the service centre these waypoints are used to locate the vehicle on a digital
road map. The algorithm that determines when and how the waypoints are set by the onboard unit is
described in CEN/TS 14821-7. Table 4-1 describes the required performance.
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Table 4-1: Positioning performance parameters for security services
Service Accuracy Availability Continuity Integrity
†
pos : £ 100 m (95% ott)
£ 300 m (99% ott)
vel: £ 2 km/h (68% ott)
‡
Emergency‡ 99%‡ 99% PMD: £ 5%
dir: £ 7° (95% ott) @ V ‡ 20 km/h
PFA: £ 30%
£ 10° (95% ott) @ V < 20 km/h
dist: 2% (95% ott)
†
pos : £ 100 m (95% ott)
£ 300 m (99% ott)
vel: £ 2 km/h (68% ott)
*
Breakdown‡ 90%‡ 85% PMD: £ 10%
dir: £ 7° (68% ott) @ V ‡ 20 km/h
Call for Help PFA: £ 30%
£ 10° (68% ott) @ V < 20 km/h
dist: 5% (68% ott)
†: For emergency and breakdown management in urban areas a position accuracy of 50 m or better is desirable.
‡: The time of an outage should not exceed 5 seconds.
*: This value is to be understood as an overall average probability of uninterrupted operation. Actual continuity may vary depending on
the environmental conditions in which the vehicle is involved.
4.2.3.2 Navigation Services
Navigation services comprise homing, route briefing and orientation assistance. Whereas the homing service
is meant to give the user only a direction and distance information between his actual position and a specified
location, the route briefing and orientation assistance services take into account actual motorways and
waypoints as well as the actual traffic situation to calculate a well defined route. Therefore navigation services
also impose stringent requirements on the performance of positioning modules of traffic telematics terminal
devices. The navigation services are described in CEN/TS 14821-6.
To locate a vehicle that has issued a route request message the onboard unit transmits a message to the
service centre that contains information about the vehicle's actual location. The format of this message is
specified in CEN/TS 14821-3. It basically consists of a chain of waypoints the vehicle has passed along its
last few kilometres. At the service centre these waypoints are used to locate the vehicle on a digital road
map. The algorithm that determines when and how the waypoints are set by the onboard unit is described in
CEN/TS 14821-7.
The required positioning performance parameters for navigation services are summarised in Table 4-2.
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Table 4-2: Positioning performance parameters for navigation services
Service Accuracy Availability Continuity Integrity
†
pos : £ 100 m (95% ott)
£ 300 m (99% ott)
vel: £ 2 km/h (68% ott)
‡
Navigation‡ 99%‡ 99% PMD: £ 5%
dir: £ 7° (95% ott) @ V ‡ 20 km/h
PFA: £ 30%
£ 10° (95% ott) @ V < 20 km/h
dist: 2% (95% ott)
†: For navigation in urban areas a position accuracy of 50 m or better is desirable.
‡: The time of an outage should not exceed 5 seconds.
4.2.3.3 Traffic Information Services
Traffic information services provide information about the traffic situation in specific areas as e.g. within a
circular area around the vehicle's actual location or in a specified geographical area. The specifications for
these services are described in CEN/TS 14821-6.
To locate a vehicle that has issued a traffic information request message the onboard unit transmits a
message to the service centre, which consists of the actual position and direction of motion of the vehicle.
The required positioning performance parameters for traffic information services are summarised in the
following table.
Table 4-3: Positioning performance parameters for traffic information services
Service Accuracy Availability Continuity
†
pos : £ 100 m (95% ott)
Traffic vel: -
‡
‡ 90%‡ 85%
Information
dir: £ 10° (68% ott) @ V ‡ 20 km/h
dist: -
†: The figure given above is valid for traffic information areas with a minimum radius of 1 km. If larger minimum radii are fixed by the
terminal equipment manufacturer a minimum position accuracy of 10 % of the minimum information area radius must be achieved.
‡: This value is to be understood as an overall average probability of uninterrupted operation. Actual continuity may vary depending on
the environmental conditions in which the vehicle is involved.
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SIST-TS CEN/TS 14821-7:2003
CEN/TS 14821-7:2003
4.2.3.4 General Information Services
The General Information Services are described in CEN/TS 14821-6.
The required positioning performance parameters for general information services are summarised in Table
4-4.
Table 4-4: Positioning performance parameters for general information services
Service Accuracy Availability Continuity
pos: £ 500 m (95% ott)
General vel: -
†
‡ 90%‡ 85%
Information dir: £ 10° (68% ott) @ V ‡ 20 km/h
dist: -
†: This value is to be understood as an overall average probability of
...
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