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1、 Reference number ISO/PAS 17684:2003(E) ISO 2003 PUBLICLY AVAILABLE SPECIFICATION ISO/PAS 17684 First edition 2003-12-01 Transport information and control systems In-vehicule navigation systems ITS message set translator to ASN.1 format definitions Systmes de commande et dinformation des transports
2、Systmes de navigation dans les vhicules Traducteur de lensemble des messages ITS en dfinitions de format ASN.1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Qatar Petroleum/5943408001 Not for Resale, 04/12/2007 00:43:18 MDTNo reproduction or
3、 networking permitted without license from IHS -,-,- ISO/PAS 17684:2003(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and i
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6、d, please inform the Central Secretariat at the address given below. ISO 2003 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in
7、writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2003 All rights reserved Copyr
8、ight International Organization for Standardization Provided by IHS under license with ISO Licensee=Qatar Petroleum/5943408001 Not for Resale, 04/12/2007 00:43:18 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/PAS 17684:2003(E) ISO 2003 All rights reserved iii Contents
9、 Page Forewordiv Introduction v 1 Scope1 2 Normative references .1 3 Terms and definitions.1 4 Message Set Tabular Form description2 4.1 General.2 4.2 MSTF description2 5 Specification of Descriptor Normal Form (DNF)7 5.1 General.7 5.2 Overview of DNF .8 5.3 DNF Notation .8 5.4 DNF character set .10
10、 5.5 DNF items.11 5.6 Simple types14 5.7 Enumerated types.18 5.8 Complex types.18 5.9 Defined types.20 5.10 Structure of a DNF specification .20 5.11 Summary of the EBNF productions for DNF21 5.12 Translation of DNF to ASN.122 Annex A (informative) Sample Encoding in MSTF24 Annex B (informative) ASN
11、.1 Reserved Words .28 Annex C (informative) A Comparison of DNF to ASN.129 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Qatar Petroleum/5943408001 Not for Resale, 04/12/2007 00:43:18 MDTNo reproduction or networking permitted without licens
12、e from IHS -,-,- ISO/PAS 17684:2003(E) iv ISO 2003 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO techn
13、ical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
14、with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft In
15、ternational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement f
16、or such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the mem
17、bers of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after th
18、ree years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International S
19、tandard or be withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/PAS 17684 was prepared by Technical Committee ISO/TC 204, Intelligent tr
20、ansport systems. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Qatar Petroleum/5943408001 Not for Resale, 04/12/2007 00:43:18 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/PAS 17684:2003(E) ISO 2003 All rights
21、 reserved v Introduction Working Group 11 of the Technical Committee ISO/TC 204 is responsible for the ITS information concerning navigation and route guidance. This committee, during the preparation of ISO 15075, Transport information and control systems In-vehicle navigation systems Communications
22、 message set requirements, realized that the ISO/IEC directives require a formal description by ASN.1 whenever an information data structure, such as message set, is defined. ASN.1 is a well-defined language with significant descriptive power; however, due to the simplicity of almost all messages us
23、ed in navigation and route guidance systems, they can be more simply expressed in tabular form. Since it is a common practice among navigation system engineers to define a message set by tables, the main part of this document specifies messages as tables. Faced with the situation of different types
24、of descriptions for a message set, one practical and the other formal, ISO/TC 204 started a project that bridges these descriptions instead of writing down one ASN.1 description for ISO 15075. This document, which allows engineers to write message sets for navigation and route guidance in a tabular
25、form that is automatically translated to ASN.1 description, is a result of that project. In many navigation systems, traffic and travel information is transferred to and from vehicles and traffic information centers via transmitted messages. To make on-board navigation units compatible with navigati
26、on facilities, each message used in the system has to be precisely defined. The internationally accepted Abstract Syntax Notation One (ASN.1) is a powerful tool for describing information data structures. ISO/IEC has agreed that data structures, such as a message set, which define a standard should
27、be formally described in ASN.1. As a consequence, ISO/TC 204 decided that information data structures such as the format of messages including navigation messages must be defined in ASN.1. Navigation engineers, however, usually use much simpler tabular forms to describe their message sets. As the de
28、gree of complexity required in descriptions of navigation message sets does not require the full descriptive power of ASN.1, it was easy to imagine that some subset of ASN.1 could be defined for a simpler description of navigation message sets. Therefore, the first task was to define the subset of A
29、SN.1 most suitable for this purpose. However, instead of directly extracting a subset of ASN.1, an intermediate language, DNF (Descriptor Normal Form; see Clause 5), was proposed. The intermediate DNF language must retain its compatibility with ASN.1, but can be simplified since most of the messages
30、 used in navigation are linear in the sense that they are simply written in the lines of a table. Thus, the descriptive power of DNF is strictly limited and any description defined by DNF should also be defined by ASN.1. This means that the set of all possible DNF descriptions is a subset of descrip
31、tions available in ASN.1. In this sense, DNF is a subset of ASN.1. The bridge between the simple DNF tabular descriptions and their respective formal ASN.1 descriptions is a compiler “dnf2asn1”. As shown in the following figure, a DNF description is translated to ASN.1 description by the compiler “d
32、nf2asn1.” Figure 1 Function of the bridge compiler dnf2asn1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Qatar Petroleum/5943408001 Not for Resale, 04/12/2007 00:43:18 MDTNo reproduction or networking permitted without license from IHS -,-,
33、- ISO/PAS 17684:2003(E) vi ISO 2003 All rights reserved With this compiling path, any navigation message set that is described in DNF is automatically converted to an ASN.1 description. By inserting an additional processing step prior to DNF, e.g. inserting another language definition and its compil
34、er to DNF, a message set described in the new language can be converted to first DNF by the new compiler and then to ASN.1 by dnf2asn1. In this way, an ASN.1 description of the original message set is generated. If the new language is based on a tabular form, then this double-bridge system can conve
35、rt a tabular-form description of a message set to its ASN.1 equivalent. It is well known that the tabular form description of message set is much easier for navigation engineers to understand, define and maintain. However, the type of tabular form which best serves this purpose has not yet been clea
36、rly defined. Therefore, this document presents an example of a tabular-form message-set description language and its compiler to DNF. Many aspects of the language were kept open for user definition so that descriptive features could be flexibly changed. As this tabular form message set/compiler is a
37、n example, it may not accommodate all the needs of a user, and thus it is recommended that a more specific message set/compiler be generated. Figure 2 Conversion of the tabular-form navigation message set into ASN.1 Copyright International Organization for Standardization Provided by IHS under licen
38、se with ISO Licensee=Qatar Petroleum/5943408001 Not for Resale, 04/12/2007 00:43:18 MDTNo reproduction or networking permitted without license from IHS -,-,- PUBLICLY AVAILABLE SPECIFICATION ISO/PAS 17684:2003(E) ISO 2003 All rights reserved 1 Transport information and control systems In-vehicule na
39、vigation systems ITS message set translator to ASN.1 format definitions 1 Scope This Publicly Available Specification specifies a method that can be used to define navigation message sets in tabular form with a subsequent translation into a corresponding ASN.1 description. An intermediate language c
40、alled Descriptor Normal Form (DNF), which is a subset of ASN.1, is specified and used as an intermediate description between a tabular form and its ASN.1 description. A tabular-form message-set description language called Message Set Tabular Form (MSTF) is included as an example of a tabular form de
41、finition. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/IEC 8824-1:1
42、998, Information technology Abstract Syntax Notation One (ASN.1): Specification of basic notation Part 1 ISO/IEC 10646-1:2000, Information technology Universal Multiple-Octet Coded Character Set (UCS) Part 1: Architecture and Basic Multilingual Plane 3 Terms and definitions For the purposes of this
43、document, the following terms and definitions apply. The following terms are defined in ISO/IEC 8824-1:1998 specification, bit string type, boolean type, character, character string types, choice types, component type, encoding, (ASN.1) encoding rules, enumerated types, false, integer type, module,
44、null type, octetstring type, real type, recursive definitions, selection types, sequence types, sequence-of types, spacing character, simple type, tag, true, type, type reference name, value, value set, white-space. 3.1 DNF character set set of characters used in the DNF notation NOTE See 5.4. 3.2 f
45、loating-point number number capable of being specified by the formula M 10E where M and E are two integers called the mantissa and the exponent, respectively Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Qatar Petroleum/5943408001 Not for Re
46、sale, 04/12/2007 00:43:18 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/PAS 17684:2003(E) 2 ISO 2003 All rights reserved 3.3 floating-point type type consisting of all possible floating-point numbers plus the two values + and - NOTE The floating-point type is a subset
47、 of the real type in ASN.1. The real type accommodates bases other than 10. 3.4 items named sequences of characters from the DNF character set which are used to form the DNF notation NOTE See 5.4. 4 Message Set Tabular Form description 4.1 General Message Set Tabular Form (MSTF) describes a message
48、set by message components. A message component is defined by a line or lines, where a line consists of a sequence of boxes or cells. Each cell contains either a string of characters or is empty. A string of characters contained in a cell may be one of the following component items: a reserved word; a data type; a data item; a special indicator composed of one or two special characters; a comment denoted by the special indicator “/”at the beginning of the comment character string. Some of the da