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1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefr
2、om, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2002 Society of Automotive Engineers, Inc. All rights reserved. No part of
3、this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER:Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4
4、970 (outside USA) Fax: 724-776-0790 Email: custsvcsae.org SAE WEB ADDRESS:http:/www.sae.org SURFACE VEHICLE 400 Commonwealth Drive, Warrendale, PA 15096-0001 STANDARD J2540 ISSUED JUL2002 Issued2002-07 Messages for Handling Strings and Look-Up Tables in ATIS Standards ForewordThis SAE Standard outli
5、nes the methodology and messages used to convey textual strings of messages to consumers in ATIS and other areas. It outlines how concepts originally developed for SAE J2369 can be expanded to cover the various types of ITIS messages used in US deployments in a consistent way and meet a number of go
6、als. Among these goals is overcoming the historical problems of obsolete tables without requiring the mutual agreement and updating of all deployed users. It provides implementation details for deployments wishing to use tables in ways ranging from non-changing (“static”) embodiments, to highly flex
7、ible and changing table structures (“dynamic”), and provides a single uniform formatting standard for all (regardless of specific content). In the related documents are encodings of selected national level tables used in various deployments. See also: SAE J2540-1 RDS Phrase Lists SAE J2540-2 ITIS Ph
8、rase Lists SAE J2540-3 National Names Phrase Lists TABLE OF CONTENTS 1.Scope. 3 2.References. 3 2.1Applicable Publications 3 2.2Related Publications. 4 3.Definitions.4 4.Overview 8 4.1Goals of the Document. 8 4.2Limits of This Approach 10 4.3Summary 13 5.Operating Concepts .14 5.1Assignment of a Tab
9、le in Use. 14 5.2Properties of a Table 14 5.3Nesting of Tables . 14 5.4Supported Vocabularies and Alphabets. 15 SAE J2540 Issued JUL2002 -2- 5.5Table Expansion Values.16 5.6Simple Text within Strings 17 5.7Registering a table within ITS.18 5.8Adding to a tables entries 18 5.9Table Resorting 18 5.10C
10、onsiderations for end user equipment19 5.11Changes to existing standards .19 6.Messages .19 6.1The Table Message 20 6.2The Partial Table Message.22 6.3The Table Request Message23 6.4The Index Translate Message23 6.5The Index Translate Request Message23 6.6The String Translate Message24 6.7The String
11、 Translate Request Message .24 7.Data Elements 24 7.1Date Element: Table-Registration-Value24 7.2Date Element: Local-Table-Flags .26 7.3Date Element: About-Flags.26 7.4Date Element: Index-Start 27 7.5Date Element: Index-Stop.27 7.6Date Element: Index-Count 28 7.7Date Element: Index-828 7.8Date Eleme
12、nt: Index-11 28 7.9Date Element: Index-12 28 7.10Date Element: Index-16 28 7.11Date Element: Table-Entry .29 7.12Date Element: Local-Number .29 7.13Date Element: Included-Table-Flags 30 7.14Date Element: Request-Type .32 7.15Date Element: Revision33 7.16Date Element: Word-Count.33 7.17Date Element:
13、Entry-Type 33 7.18Date Element: CRC-16.34 7.19Date Element: SAE-String 34 8Using This Document in Other Messages 35 8.1General Comments for Use35 8.2Connecting Strings across Multiple Message Fields 36 8.3Examples of use in SAE J2354 36 8.4Examples of use in SAE J2369 37 Table 1Typical Multi-Part Ph
14、rase Table11 Table 2Latin_1 Character Excluded By Current SAE J2369 Codings13 Table 3Types of Tables and Their Exception Tokens 16 Table 4Example of Table Control Expansion Bits (From SAE J2369 Table 8).16 Table 5Example of Numeric Table Control Expansion Bits (From SAE J2369 Table 9) 17 Table 6Tabl
15、e Registration Value Ranges.25 Table 7Reserved Table Registration Values 25 Table 8Assigned Local Table Numbers 29 Table 9Reserved Table Numbering Assignments 30 Table 10Incident Flow Context Table Entries (From Table 24 of SAE J2369) .37 SAE J2540 Issued JUL2002 -3- 1.ScopeThis SAE Standard defines
16、 methods and messages to efficiently translate sequences of text and other types of data into and out of indexed values and look-up tables for effective transmission. This document defines: a.Methods and Data Elements for handling indexes and strings in ATIS applications and message sets b.Message S
17、ets to support the delivery and translations of tables used in such strings c.Tables of Nationally standardized strings for use in ATIS message descriptions And examples of each in illustrative portions. While developed for ATIS use, the methods defined in this document are useful for any textual st
18、rings in any Telematics applications found both in Intelligent Vehicles and elsewhere. 2.References 2.1Applicable PublicationsThe following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest version of SAE publications shall apply. 2
19、.1.1SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. SAE J2313On-Board Land Vehicle Mayday Reporting Interface, May 2000 SAE J2353Data Dictionary for Advanced Traveler Information Systems (ATIS), October 1999 SAE J2354Message Sets for Advanced Traveler Informati
20、on Systems (ATIS), October 2000 SAEJ2369Standards for ATIS Message Sets Delivered Over Reduced Bandwidth Media, November 2000 SAEJ2374Information Report based on Location Reference Message Specification, Rev. B (MDI), May22, 1997 SAE J2540-1RDS Phrase Lists SAE J2540-2ITIS Phrase Lists SAE J2540-3Na
21、tional Names Phrase Lists 2.1.2ANSI PUBLICATIONAvailable from ANSI, 25 West 43rd Street, New York, NY 10036-8002. ANSI X3.4American National Standard Code for Information Interchange 2.1.3CEN PUBLICATIONSAvailable from CEN, 36 rue de Stassart, B-1050 Brussels, Belgium. Traffic and Traveller1 Informa
22、tion (TTI) TTI Messages via Traffic Message Coding- Part I: Coding protocol for Radio Data Systems Traffic Message Channel (RDS-TMS) using ALERT-C, ISO/DIS 14819-1, August 1999 Traffic and Traveller Information (TTI) TTI Messages via Traffic Message Coding- Part 2: Event and Information codes for Tr
23、affic Message Channel (TMC), PrENV 12313-2, Version 1.0, June 1996 2.1.4GATS PUBLICATIONSAvailable from the GATS forum or from CEN TC278. GATS Message Set; Main Part Main 2034.pdf 05.08.99 GATS Message Set; Annex 2 - Basic Information Elements A2_2033.pdf 05.08.99 2.1.5ISO PUBLICATIONAvailable from
24、ANSI, 25 West 43rd Street, New York, NY 10036-8002. ISO prEN 14819-1 (1999) 1.European spelling of Traveler SAE J2540 Issued JUL2002 -4- 2.2Related PublicationsThe following publications are provided for information purposes only and are not a required part of this document. 2.2.1SAE PUBLICATIONSAva
25、ilable from SAE, 400 Commonwealth drive, Warrendale, PA 15096-0001. SAE J2353Data Dictionary for Advanced Traveler Information Systems (ATIS), October 1999 SAEJ2374Information Report based on Location Reference Message Specification, Rev. B (MDI), May 22, 1997 2.2.2FHWA PUBLICATIONSAvailable from Le
26、e Simmons, FHWA, HVH-1 Room 3400, 400 7th Street SW, Washington, D.C. 20590. National ITS Architecture, Federal Highway Administration, U.S. Department of Transportation, Version 2.0, September 1998 2.2.3ITE PUBLICATIONSAvailable from ITE, 525 School Street SW, Suite 410, Washington, DC 20024. Messa
27、ge Sets for External Traffic Management Center Communication (MS/ETMC2), TM 2.01, Rev. 2.0, February 1, 2001 2.2.4W3C PUBLICATIONSAvailable from W3C, http:/www.w3.org. “Hypertext Transfer Protocol - HTTP/1.1,” W3C - June 1999, RFC 2616, available at http:/www.w3.org/ Protocols/rfc2616/rfc2616.txt “H
28、TML 4.0 Specification,” W3C - December 1997, revised 24 April 1998 available at http:/www.w3.org/TR/ 1998/REC-html40-19980424 HTML 4.0 Guidelines for Mobile Access W3C Note - 15 March 1999 available at http:/www.w3.org/TR/ NOTE-html40-mobile Character Model for the World Wide Web, World Wide Web Con
29、sortium Working Draft 29-November-1999 available at http:/www.w3.org/TR/1999/WD-charmod-19991129/. 3.DefinitionsThe following terms and concepts are used in the body of this document. 3.1Alert-CA traffic message system using phrase - index encodings operating over RDS and established in 1990, see IS
30、O prEN 14819-1 (1999) for current information. Along with a more advanced system called Alert- Plus (and typically a pay for service system) this system has been deployed in selected major cites in Europe. Typically under local government sponsorship. A number of early US deployments by Enterprise S
31、tates have used derivative versions of the phrases established in this work for trial US deployments. A number of commercial vendors support derivative forms of it, both on RDS and on other media as well. 3.2CompressionThe process of replacing a sequence of simple text elements (or other strings) wi
32、th a small index value for transmission is considered to be compression in this document. 3.3Dense TableA table where the index values increase by one each time without a break in the ordering. The index value can be implicitly computed and therefore need not be sent. Dense tables are preferred, and
33、 are easier to automatically generate than sparse tables. 3.4Dynamic TableA table which changes its contents periodically as a function of the textual information which is being transmitted and which attempts to reflect to achieve the best compression in the media. As contrasted with static tables w
34、hich only change periodically. Strategies affecting the frequency of updating vary with implementation, media, and ISP operators choices. Dynamic tables convey their changes over the same media as the messages using them. This is an essential aspect of their operation. SAE J2540 Issued JUL2002 -5- 3
35、.5End Using DeviceA term used in this document to refer to the device which received the message and strings that are a subject of this document. The capabilities of such a device may vary widely from one user to another. The device is presumed to be mobile, but need not be. The end using device get
36、s its data from the issuing ISP over the host media. 3.6ExceptionA token which causes some change in the flow of control in processing the stream. In this document, exception tokens precede an index value and are used to select which table (and how) to expand from. 3.7ExpansionThe process of replaci
37、ng an index value found in a string with the corresponding string or text value which it represents. 3.8Expansion CodeThe code which precedes an index value (also called an exception token). This code selects which of up to four tables is to be used in expanding the string back into text and provide
38、s some control flags for how the expansion is to occur. 3.9Extending a TableThe act of adding additional index entries to the end of an existing table. All tables can be extended. By this means new entries are added as needed while preserving the older index values. Periodically a resort may occur w
39、hich reassigns the mapping of index values. The revision bits allow the end user to determine if a table has been extended and/or resorted. 3.10 FlagsOne or more bit values contained in some part of a message which effect the way a string is processed in converting it back into text. In the table me
40、ssage there are flags dealing with how the table itself, and how any included tables, are to be handled. 3.11 Flat TableA table whose entries do not contain indexes to any other tables, i.e., a table which is entirely self contained. A flat table may contain nested table entries to itself. 3.12 GATS
41、Global Automotive Telematics Standard. A mobile phone system based on the GSM (Global System for Mobile Communication) phone system deployed in Germany and other areas of Europe. The GATS systems provides a message set which offers many of the same services in US ITS-ATIS. GATS is being advanced by
42、the CEN TC278 process as a standard. 3.13 Group 8AThe original message type used in RDS to carry TMC messages in a complete 37-bil message. Now such messages can be carried in any valid spare group by means of a soft assignment process called ODA. 3.14 Host MediumThe host media are the transmission
43、media that was used to transport the ATIS messages containing the string from the ISP to the end-using device (e.g., wireless data links, SubCarriers, digital phones, etc.). Often such media have a limited amount of bandwidth and it is for this reason that the string handling methods of this documen
44、t were developed. 3.15 Included Table FlagsFlags providing information about tables used in the entries of this table, found in the table header. 3.16 ISPInformation Service Provider. In the context of this document the issuing source of data formatted into ATIS messages containing strings handled i
45、n accordance with this document. No presumption is made in this document regarding the business model or ownership of the ISP. The term ISP (as opposed to TMC) is often used to imply a private “for profit” venture. No such term is implied here. 3.17 ITISInternational Traveler Information System A te
46、rm coined to indicate the area of common phrases for describing incident events. SAE J2540 Issued JUL2002 -6- 3.18 Local ReplacementA term for a table entry which “overlaps” another entry in another table with the same index value. This allow the creation of local tables which can redefine a previou
47、s entry. See also “overlapping” and 5.3 of the text. 3.19 Local Table FlagsFlags providing information about the tables found in the table header. 3.20 Local Table NumberA value assigned to any table used by the ISP in its messages. Used to relate specific strings to this table (and any underlying t
48、ables). 3.21 LRMSLocation Referencing Message Set A body of work outlining a number of “profiles” used in the description of affected areas, typically roadway segments. The preferred methodology for use in ATIS is the ISP Vehicle profile (SAE J1746) which provides a means to send Lat-Long values bet
49、ween the ISP and the vehicle. A highly compressed form of this is the GRID profile which is suitable for limited bandwidth applications. Indexing values, which typically require prior agreement between users, are called Geometry profiles in this body of work. The LMRS is expected to become an SAE Standard in the future and will reflect all the profiles then used, including indexes. 3.22 Modified ASCIIThis is a derivative of the ASCII character set specified in detail in SAE J2369. It uses the upper encoding values (