ISO 22643:2003

Overview

ISO 22643:2003 - titled Space data and information transfer systems - Data entity dictionary specification language (DEDSL) - XML/DTD Syntax - specifies the requirements for an XML/DTD syntax to express a Data Entity Dictionary Specification Language (DEDSL). Adopted from CCSDS 647.3-B-1, this International Standard defines a machine-readable, standardized notation for describing data entity dictionaries used in space data and information transfer systems to enable consistent metadata representation and interchange.

Key Topics and Requirements

• DEDSL to XML/DTD mapping: Defines how the DEDSL abstract syntax maps to XML elements, attributes and a Document Type Declaration (DTD) (see Clause 2 and Table 2-1).
• Complete DEDSL dictionary model: Provides a full XML/DTD representation for a data entity dictionary suitable for construction and interchange (Clause 2.3).
• Dictionary identification: Rules for naming, versioning, language, character set and external references (Clause 3).
• Data entity definition: Structure for identifying, definitional, relational and representational attributes of data entities (Clause 4).
• User-defined attribute definitions: Mechanisms to define custom attributes, types (integer, real, text, enumerated, entity), defaults, inheritance and examples (Clause 5).
• Conformance levels: Two conformance levels - notation compliance and interoperability compliance - guide implementations and interoperability testing (Clause 6).
• DTD and reserved keywords: Provides the DTD and a list of reserved keywords to ensure consistent parser behavior (Clauses 7–8).
• Examples and references: Annex A contains illustrative examples; Annex B lists informative references to related CCSDS/ISO documents.

Applications and Who Uses It

ISO 22643:2003 is intended for organizations that need standardized metadata and dictionary exchange in space systems:

• Space agencies and mission data centers - for cataloging mission data, telemetry and payload datasets.
• Data architects and systems engineers - to design interoperable metadata schemas and metadata registries.
• Software developers and integrators - building tools for dictionary creation, validation, and automated parsing using XML/DTD.
• Archives and science data centers - ensuring long-term data discoverability and consistent attribute semantics across agencies.

Benefits include improved interoperability, machine validation via DTD, and easier sharing of data definitions across international space programs.

Related Standards

• Based on CCSDS 647.3-B-1 (DEDSL - XML/DTD Syntax).
• References include CCSDS/ISO documents such as CCSDS 647.1-B-1 (equivalent to ISO 21961:2003) and other CCSDS standards addressing space data transfer and metadata.

Keywords: ISO 22643:2003, DEDSL, XML/DTD, data entity dictionary, space data, CCSDS, metadata standard, data interchange.