ISO 17107:2011

Space data and information transfer systems - XML specification for navigation data messages

ISO 17107:2011 specifies a format for use in exchanging spacecraft navigation data. Such exchanges are used for distributing attitude, orbit, and tracking data between space agencies. ISO 17107:2011 specifies an integrated Extensible Markup Language (XML) schema set that applies to Navigation Data Messages (NDMs) defined in the CCSDS Recommended Standards for Attitude Data Messages (ADM), Orbit Data Messages (ODM), and Tracking Data Message (TDM). This XML schema set is suited to inter-agency exchanges of any number of NDMs (ADM, ODM, and/or TDM). ISO 17107:2011 is applicable only to the schema content and layout, and to instantiations of the schema, but not to the transmission of any instantiation of the schema. The potential for compression/decompression of the message is an aspect of the transmission that is not part of this specification. The means of transmission of an XML-formatted NDM between agencies is beyond the scope of ISO 17107:2011; such arrangements require specification via other means, for example, in an Interface Control Document (ICD).

Systèmes de transfert des informations et données spatiales — Spécifications XML pour les messages de données de navigation

General Information

• Status: Published
• Publication Date: 07-Nov-2011
• ICS: 49.140 - Space systems and operations
• Technical Committee: ISO/TC 20/SC 13 - Space data and information transfer systems
• Drafting Committee: ISO/TC 20/SC 13 - Space data and information transfer systems
• Current Stage: 9093 - International Standard confirmed
• Start Date: 14-Nov-2023
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 5182:2016 - Resistance welding - Materials for electrodes and ancillary equipment
• Effective Date: 06-Jun-2022

Overview

ISO 17107:2011 - Space data and information transfer systems - XML specification for navigation data messages - defines an integrated XML schema set for exchanging spacecraft navigation data. Adopted from CCSDS 505.0-B-1, this International Standard standardizes the XML format for Navigation Data Messages (NDMs) used to distribute attitude, orbit and tracking data between space agencies. ISO 17107:2011 applies to the schema content and layout and to instantiations of that schema (NDM/XML files), but does not specify transmission, compression or transport mechanisms.

Key topics and requirements

• NDM XML schema set: A unified schema that covers CCSDS message families - ADM (Attitude Data Messages), ODM (Orbit Data Messages), and TDM (Tracking Data Messages).
• Message structure: Guidance on NDM composition - standard header, metadata and data sections - and support for single or combined NDMs in one XML instance.
• Substructures: Definitions and intent for subcomponents referenced in the standard (for example AEM/APM and OEM/OMM/OPM/TDM segment types) to represent different navigation message types and multiplicities.
• Schema content and layout rules: Constraints and expected element/attribute usage to ensure interoperability of XML instantiations across agencies.
• Extensibility and versioning: Schema design intended to allow agency-specific subsets and controlled extensions while maintaining baseline compatibility.
• Informative annexes: Examples of XML instantiations, rationale for the XML approach, security considerations and reference materials to support implementation.

Applications

• Inter-agency navigation data exchange: Routine sharing of orbit ephemerides, attitude profiles and tracking observations between space agencies and ground-segment organizations.
• Mission operations and GN&C: Flight dynamics, guidance, navigation & control teams use NDM/XML for orbit determination, attitude analysis and planning.
• Data archiving and interchange: Standardized XML files for long-term archives, data cataloging and cross-mission data interoperability.
• Software and tools: Developers of mission control software, orbit propagation tools, and tracking-data processors implement the NDM/XML schema to ensure consistent input/output formats.

Who should use this standard

• Space agencies and mission operations centers
• Flight dynamics and GN&C engineers
• Ground-segment system integrators and software developers
• Systems architects drafting Interface Control Documents (ICDs) for inter-agency exchanges
• Data managers and archive custodians

Related standards

• CCSDS 505.0-B-1 (XML Specification for Navigation Data Messages) - basis for ISO 17107:2011
• CCSDS/ISO references noted in the standard: CCSDS 504.0-B-1 (ISO 13541:2010), CCSDS 503.0-B-1 (ISO 13526:2010) and related CCSDS documents for ADM/ODM/TDM message definitions.

Keywords: ISO 17107:2011, Navigation Data Messages, NDM XML, ADM, ODM, TDM, CCSDS, spacecraft navigation data, inter-agency data exchange, XML schema.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17107
First edition
2011-11-15
Space data and information transfer
systems — XML specification for
navigation data messages
Systèmes de transfert des informations et données spatiales —
Spécifications XML pour les messages de données de navigation

Reference number
©
ISO 2011
©  ISO 2011
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 writing from either ISO at the address below or
ISO's 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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – 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
technical 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 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 International 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.
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 17107 was prepared by the Consultative Committee for Space Data Systems (CCSDS) as
CCSDS 505.0-B-1, December 2010 and was adopted without modifications except those stated in Clause 2 of
this International Standard by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 13, Space data and information transfer systems.

INTERNATIONAL STANDARD ISO 17107:2011(E)

Space data and information transfer systems — XML
specification for navigation data messages
1 Scope
This International Standard specifies a format for use in exchanging spacecraft navigation data. Such
exchanges are used for distributing attitude, orbit, and tracking data between space agencies. This
International Standard specifies an integrated Extensible Markup Language (XML) schema set that applies to
Navigation Data Messages (NDMs) defined in the CCSDS Recommended Standards for Attitude Data
Messages (ADM), Orbit Data Messages (ODM), and Tracking Data Message (TDM).
This XML schema set is suited to inter-agency exchanges of any number of NDMs (ADM, ODM, and/or TDM).
This International Standard is applicable only to the schema content and layout, and to instantiations of the
schema, but not to the transmission of any instantiation of the schema. The potential for
compression/decompression of the message is an aspect of the transmission that is not part of this specification.
The means of transmission of an XML-formatted NDM between agencies is beyond the scope of this
International Standard; such arrangements require specification via other means, for example, in an Interface
Control Document (ICD).
The scope and field of application are furthermore detailed in subclauses 1.2 to 1.4 of the enclosed CCSDS
publication.
2 Requirements
Requirements are the technical recommendations made in the following publication (reproduced on the
following pages), which is adopted as an International Standard:
CCSDS 505.0-B-1, December 2010, XML Specification for Navigation Data Messages.
For the purposes of international standardization, the modifications outlined below shall apply to the specific
clauses and paragraphs of publication CCSDS 505.0-B-1.
Pages i to vi
This part is information which is relevant to the CCSDS publication only.
Page 1-3
Add the following information to the reference indicated:
[1] Document CCSDS 504.0-B-1, May 2008, is equivalent to ISO 13541:2010.
1)
[2] Document CCSDS 502.0-B-2, November 2009, is equivalent to ISO 26900:— .
[3] Document CCSDS 503.0-B-1, November 2007, is equivalent to ISO 13526:2010.

1) To be published.
3 Revision of publication CCSDS 505.0-B-1
It has been agreed with the Consultative Committee for Space Data Systems that Subcommittee
ISO/TC 20/SC 13 will be consulted in the event of any revision or amendment of publication
CCSDS 505.0-B-1. To this end, NASA will act as a liaison body between CCSDS and ISO.

2 © ISO 2011 – All rights reserved

Recommendation for Space Data System Standards
XML SPECIFICATION
FOR NAVIGATION
DATA MESSAGES
RECOMMENDED STANDARD
CCSDS 505.0-B-1
BLUE BOOK
December 2010
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4 © ISO 2011 – All rights reserved

XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
AUTHORITY
Issue: Recommended Standard, Issue 1
Date: December 2010
Location: Washington, DC, USA
This document has been approved for publication by the Management Council of the
Consultative Committee for Space Data Systems (CCSDS) and represents the consensus
technical agreement of the participating CCSDS Member Agencies. The procedure for
review and authorization of CCSDS documents is detailed in the Procedures Manual for the
Consultative Committee for Space Data Systems, and the record of Agency participation in
the authorization of this document can be obtained from the CCSDS Secretariat at the
address below.
This document is published and maintained by:

CCSDS Secretariat
Space Communications and Navigation Office, 7L70
Space Operations Mission Directorate
NASA Headquarters
Washington, DC 20546-0001, USA
CCSDS 505.0-B-1 Page i December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
STATEMENT OF INTENT
The Consultative Committee for Space Data Systems (CCSDS) is an organization officially
established by the management of its members. The Committee meets periodically to address
data systems problems that are common to all participants, and to formulate sound technical
solutions to these problems. Inasmuch as participation in the CCSDS is completely voluntary,
the results of Committee actions are termed Recommended Standards and are not
considered binding on any Agency.
This Recommended Standard is issued by, and represents the consensus of, the CCSDS
members. Endorsement of this Recommendation is entirely voluntary. Endorsement,
however, indicates the following understandings:
o Whenever a member establishes a CCSDS-related standard, this standard will be in
accord with the relevant Recommended Standard. Establishing such a standard
does not preclude other provisions which a member may develop.
o Whenever a member establishes a CCSDS-related standard, that member will
provide other CCSDS members with the following information:
-- The standard itself.
-- The anticipated date of initial operational capability.
-- The anticipated duration of operational service.
o Specific service arrangements shall be made via memoranda of agreement. Neither
this Recommended Standard nor any ensuing standard is a substitute for a
memorandum of agreement.
No later than five years from its date of issuance, this Recommended Standard will be
reviewed by the CCSDS to determine whether it should: (1) remain in effect without change;
(2) be changed to reflect the impact of new technologies, new requirements, or new
directions; or (3) be retired or canceled.
In those instances when a new version of a Recommended Standard is issued, existing
CCSDS-related member standards and implementations are not negated or deemed to be non-
CCSDS compatible. It is the responsibility of each member to determine when such
standards or implementations are to be modified. Each member is, however, strongly
encouraged to direct planning for its new standards and implementations towards the later
version of the Recommended Standard.
CCSDS 505.0-B-1 Page ii December 2010
6 © ISO 2011 – All rights reserved

XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
FOREWORD
This document is a technical Recommended Standard for an XML Specification for
Navigation Data Messages (Orbit Data Messages, Attitude Data Messages, Tracking Data
Messages). This Recommended Standard has been developed via consensus of the
Navigation Working Group of the CCSDS Mission Operations and Information Management
Services (MOIMS) area. The XML schema set described in this Recommended Standard
represents the baseline concept for exchanging navigation data in XML format between
Agencies of the CCSDS.
This Recommended Standard establishes a common framework and provides a common
basis for the interchange of navigation data in XML format. It allows implementing
organizations within each Agency to proceed coherently with the development of compatible
derived standards for the flight and ground systems that are within their cognizance. Derived
Agency standards may implement only a subset of the optional features allowed by the
Recommended Standard and may incorporate features not addressed by this Recommended
Standard.
Through the process of normal evolution, it is expected that expansion, deletion, or
modification of this document may occur. This Recommended Standard is therefore subject
to CCSDS document management and change control procedures, which are defined in the
Procedures Manual for the Consultative Committee for Space Data Systems. Current
versions of CCSDS documents are maintained at the CCSDS Web site:
http://www.ccsds.org/
Questions relating to the contents or status of this document should be addressed to the
CCSDS Secretariat at the address indicated on page i.
CCSDS 505.0-B-1 Page iii December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
At time of publication, the active Member and Observer Agencies of the CCSDS were:
Member Agencies
– Agenzia Spaziale Italiana (ASI)/Italy.
– Canadian Space Agency (CSA)/Canada.
– Centre National d’Etudes Spatiales (CNES)/France.
– China National Space Administration (CNSA)/People’s Republic of China.
– Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)/Germany.
– European Space Agency (ESA)/Europe.
– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.
– Japan Aerospace Exploration Agency (JAXA)/Japan.
– National Aeronautics and Space Administration (NASA)/USA.
– Federal Space Agency (FSA)/Russian Federation.
– UK Space Agency/United Kingdom.
Observer Agencies
– Austrian Space Agency (ASA)/Austria.
– Belgian Federal Science Policy Office (BFSPO)/Belgium.
– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.
– China Satellite Launch and Tracking Control General, Beijing Institute of Tracking
and Telecommunications Technology (CLTC/BITTT)/China.
– Chinese Academy of Sciences (CAS)/China.
– Chinese Academy of Space Technology (CAST)/China.
– Commonwealth Scientific and Industrial Research Organization (CSIRO)/Australia.
– CSIR Satellite Applications Centre (CSIR)/Republic of South Africa.
– Danish National Space Center (DNSC)/Denmark.
– Departamento de Ciência e Tecnologia Aeroespacial (DCTA)/Brazil.
– European Organization for the Exploitation of Meteorological Satellites
(EUMETSAT)/Europe.
– European Telecommunications Satellite Organization (EUTELSAT)/Europe.
– Geo-Informatics and Space Technology Development Agency (GISTDA)/Thailand.
– Hellenic National Space Committee (HNSC)/Greece.
– Indian Space Research Organization (ISRO)/India.
– Institute of Space Research (IKI)/Russian Federation.
– KFKI Research Institute for Particle & Nuclear Physics (KFKI)/Hungary.
– Korea Aerospace Research Institute (KARI)/Korea.
– Ministry of Communications (MOC)/Israel.
– National Institute of Information and Communications Technology (NICT)/Japan.
– National Oceanic and Atmospheric Administration (NOAA)/USA.
– National Space Agency of the Republic of Kazakhstan (NSARK)/Kazakhstan.
– National Space Organization (NSPO)/Chinese Taipei.
– Naval Center for Space Technology (NCST)/USA.
– Scientific and Technological Research Council of Turkey (TUBITAK)/Turkey.
– Space and Upper Atmosphere Research Commission (SUPARCO)/Pakistan.
– Swedish Space Corporation (SSC)/Sweden.
CCSDS 505.0-B-1 Page iv December 2010
8 © ISO 2011 – All rights reserved

XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
– United States Geological Survey (USGS)/USA.
CCSDS 505.0-B-1 Page v December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
DOCUMENT CONTROL
Document Title Date Status
CCSDS XML Specification for Navigation December Current issue
505.0-B-1 Data Messages, Recommended 2010
Standard, Issue 1
CCSDS 505.0-B-1 Page vi December 2010
10 © ISO 2011 – All rights reserved

XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
CONTENTS
Section Page
1 INTRODUCTION. 1-1

1.1 PURPOSE . 1-1
1.2 SCOPE AND APPLICABILITY . 1-1
1.3 RATIONALE . 1-1
1.4 STRUCTURE OF THIS DOCUMENT. 1-1
1.5 CONVENTIONS AND DEFINITIONS . 1-2
1.6 REFERENCES . 1-3

2 OVERVIEW . 2-1

2.1 NAVIGATION DATA MESSAGES . 2-1
2.2 EXTENSIBLE MARKUP LANGUAGE . 2-2
2.3 SPECIAL CONSIDERATIONS . 2-4

3 BASIC STRUCTURE OF THE NDM/XML SCHEMA SET . 3-1

3.1 NAVIGATION DATA MESSAGES AND THE ASSOCIATED SCHEMA SET 3-1
3.2 NDM/XML BASIC STRUCTURE . 3-3
3.3 SUBSTRUCTURE 1: APM, OMM, OPM . 3-3
3.4 SUBSTRUCTURE 2: AEM, OEM, TDM. 3-3
3.5 NDM/XML TAGS . 3-4
3.6 NDM/XML TEXT VALUES . 3-5

4 CONSTRUCTING AN NDM/XML INSTANCE . 4-1

4.1 OVERVIEW . 4-1
4.2 XML VERSION . 4-1
4.3 BEGINNING THE INSTANTIATION: ROOT ELEMENT TAG . 4-1
4.4 THE STANDARD NDM/XML HEADER SECTION . 4-3
4.5 THE NDM BODY SECTION . 4-3
4.6 THE NDM METADATA SECTION . 4-3
4.7 THE NDM DATA SECTION . 4-4
4.8 CREATING AN AEM INSTANTIATION . 4-4
4.9 CREATING AN APM INSTANTIATION . 4-8
4.10 CREATING AN OEM INSTANTIATION . 4-13
4.11 CREATING AN OMM INSTANTIATION . 4-17
4.12 CREATING AN OPM INSTANTIATION . 4-18
4.13 CREATING A TDM INSTANTIATION . 4-22
4.14 CREATING AN NDM COMBINED INSTANTIATION . 4-23
4.15 DISCUSSION . 4-23
CCSDS 505.0-B-1 Page vii December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
4.16 USER DEFINED PARAMETERS . 4-27
CCSDS 505.0-B-1 Page viii December 2010
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
CONTENTS (continued)
Section Page
ANNEX A INFORMATION SECURITY (INFORMATIVE) . A-1
ANNEX B EXAMPLE NDM/XML SCHEMA INSTANTIATIONS
(INFORMATIVE) .B-1
ANNEX C INFORMATIVE REFERENCES (INFORMATIVE) . C-1
ANNEX D RATIONALE FOR XML-FORMAT NAVIGATION DATA
MESSAGES (INFORMATIVE) . D-1
ANNEX E ABBREVIATIONS AND ACRONYMS (INFORMATIVE) .E-1
Figure
3-1 NDM/XML Substructure 1 (Single Segment) . 3-3
3-2 NDM/XML Substructure 2 (Possible Multiplicity of Segments) . 3-4
4-1 Comparison of Single/Multiple Message NDMs . 4-24
4-2 NDM/XML Combined Instantiation Basic Structure . 4-25
4-3 Combined NDM/XML Instantiation with Multiple Message Types . 4-26
B-1 Sample NDM/XML AEM . B-2
B-2 Sample NDM/XML AEM with Rotation . B-4
B-3 Sample NDM/XML APM . B-5
B-4 Sample NDM/XML OEM . B-7
B-5 Sample NDM/XML OEM, Version 1 Compatible . B-9
B-6 Sample NDM/XML OMM . B-11
B-7 Sample NDM/XML OPM . B-13
B-8 Sample NDM/XML OPM Version 1 . B-15
B-9 Sample NDM/XML TDM . B-16

Table
3-1 The NDM/XML Schema Set . 3-2
4-1 NDM/XML Root Element Tags . 4-1
D-1 Primary Requirements . D-2
D-2 Heritage Requirements. D-2
D-3 Desirable Characteristics . D-3

CCSDS 505.0-B-1 Page ix December 2010
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
1 INTRODUCTION
1.1 PURPOSE
This Recommended Standard specifies a format for use in exchanging spacecraft navigation
data. Such exchanges are used for distributing attitude, orbit, and tracking data between space
agencies. The Recommended Standard specifies an integrated Extensible Markup Language
(XML) schema set that applies to Navigation Data Messages (NDMs) defined in the CCSDS
Recommended Standards for Attitude Data Messages (ADM, reference [1]), Orbit Data
Messages (ODM, reference [2]), and Tracking Data Message (TDM, reference [3]).
This XML schema set is suited to inter-agency exchanges of any number of NDMs (ADM,
ODM, and/or TDM).
1.2 SCOPE AND APPLICABILITY
This Recommended Standard is applicable only to the schema content and layout, and to
instantiations of the schema, but not to the transmission of any instantiation of the schema.
The potential for compression/decompression of the message is an aspect of the transmission
that is not part of this specification. The means of transmission of an XML-formatted NDM
between agencies is beyond the scope of this document; such arrangements require
specification via other arrangements, for example, in an Interface Control Document (ICD).
Transmission of an XML-formatted NDM could be based on a future CCSDS real-time data
transfer service, a file-based transfer protocol such as SFTP, streaming media, email, or
services provided via the World Wide Web and XML-compatible Web browsers. In general,
it is a requirement that the transmission mechanism not place constraints on the technical
data content of an NDM.
1.3 RATIONALE
This document responds to a requirement levied by the CCSDS to produce an XML format for
NDMs. It includes sets of requirements and criteria that the XML schema set has been
designed to meet. The rationale behind the design of the schema set is described in annex D in
order to assist the application engineer in constructing a suitable message.
1.4 STRUCTURE OF THIS DOCUMENT
Section 1 (this section) provides an introduction, scope, normative references, and the
description of the document structure.
Section 2 provides a very brief overview of the individual messages that constitute an NDM
(i.e., ADM, ODM, and TDM). It also provides a very brief overview of XML, and the
justification for an integrated NDM/XML schema set.
CCSDS 505.0-B-1 Page 1-1 December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
Section 3 provides an overview of the basic structure of the NDM/XML schema set. This
structure is external to the internal structure provided by the constituent messages.
Section 4 provides detailed discussion of the differences between the XML-formatted
messages and the Keyword Value Notation (KVN) text formatted messages described in
references [1], [2], and [3]. Instructions for how to construct instantiations of the various
message types are provided.
Annex A discusses information security considerations.
Annex B provides instructions on where to find the schema set referenced in this standard on
the CCSDS Web site. Also provided for illustrative purposes are a number of example
instantiations of NDM/XML messages.
Annex C contains a list of informative references.
Annex D lists a set of requirements that were taken into consideration in the design of the
NDM/XML schema.
Annex E is a list of abbreviations and acronyms applicable to the NDM/XML.
1.5 CONVENTIONS AND DEFINITIONS
1.5.1 NOMENCLATURE
The following conventions apply throughout this Recommended Standard:
a) the words ‘shall’ and ‘must’ imply a binding and verifiable specification;
b) the word ‘should’ implies an optional, but desirable, specification;
c) the word ‘may’ implies an optional specification;
d) the words ‘is’, ‘are’, and ‘will’ imply statements of fact.
1.5.2 TERMS
For the purposes of this document, the following definitions apply:
CamelCase: a style of capitalization in which the initial characters of concatenated words are
capitalized.
lowerCamelCase: a variant on CamelCase in which the first character of a character string
formed from concatenated words is lowercase. In the case of a character string consisting of
only a single word, only lowercase characters are used.
ASCII: a text character set defined in reference [C4].
CCSDS 505.0-B-1 Page 1-2 December 2010
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
1.6 REFERENCES
The following documents contain provisions which, through reference in this text, constitute
provisions of this Recommended Standard. At the time of publication, the editions indicated
were valid. All documents are subject to revision, and users of this Recommended Standard
are encouraged to investigate the possibility of applying the most recent editions of the
documents indicated below. The CCSDS Secretariat maintains a register of currently valid
CCSDS Recommended Standards.
[1] Attitude Data Messages. Recommendation for Space Data System Standards, CCSDS
504.0-B-1. Blue Book. Issue 1. Washington, D.C.: CCSDS, May 2008.
[2] Orbit Data Messages. Recommendation for Space Data System Standards, CCSDS
502.0-B-2. Blue Book. Issue 2. Washington, D.C.: CCSDS, November 2009.
[3] Tracking Data Message. Recommendation for Space Data System Standards, CCSDS
503.0-B-1. Blue Book. Issue 1. Washington, D.C.: CCSDS, November 2007.
[4] Henry S. Thompson, et al., eds. XML Schema Part 1: Structures. 2nd ed. W3C
Recommendation. N.p.: W3C, October 2004.  xmlschema-1-20041028/>
[5] Paul V. Biron and Ashok Malhotra, eds. XML Schema Part 2: Datatypes. 2nd Edition.
W3C Recommendation. N.p.: W3C, October 2004.  xmlschema-2-20041028/>
NOTE – Informative references are provided in annex C.

CCSDS 505.0-B-1 Page 1-3 December 2010
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
2 OVERVIEW
2.1 NAVIGATION DATA MESSAGES
2.1.1 GENERAL
This subsection provides a brief overview of the set of Navigation Data Messages (NDMs).
There are three basic types of NDM: Attitude Data Messages (reference [1]), Orbit Data
Messages (reference [2]), and the Tracking Data Message (reference [3]). The remainder of
this document conveys the structure of the NDMs in an integrated XML schema set.
2.1.2 ATTITUDE DATA MESSAGES
Attitude Data Messages (ADM) comprise two message types used to convey spacecraft
attitude information: the Attitude Parameter Message (APM) and Attitude Ephemeris
Message (AEM). The APM consists of an instantaneous attitude state and optional attitude
maneuvers. The AEM consists of a history/forecast of the attitude of the object; the
history/forecast can be interpolated to obtain the attitude of the spacecraft at times other than
those specified in the message. The APM and AEM are specified in reference [1].
2.1.3 ORBIT DATA MESSAGES
Orbit Data Messages (ODM) comprise three message types used to convey trajectory
information: the Orbit Parameter Message (OPM), Orbit Mean Elements Message (OMM),
and Orbit Ephemeris Message (OEM). The OPM consists of a single state vector at a given
time that can be propagated to generate the trajectory of the spacecraft; specifications of
maneuvers are optional. Like the OPM, the OMM also represents an orbit state, but it is
calculated on the basis of mean orbital elements instead of osculating elements (there are
other differences as well). The OEM represents a history/forecast of state vectors that can be
interpolated to obtain the state of the spacecraft at times other than those explicitly specified
in the message. The OPM, OMM, and OEM are specified in reference [2].
2.1.4 TRACKING DATA MESSAGE
The Tracking Data Message (TDM) is a single message type for use in exchanging spacecraft
tracking data between space agencies. Such exchanges are used for distributing tracking data
output from interagency cross supports in which spacecraft missions managed by one agency
are tracked from a ground station managed by a second agency. Additionally, the ability to
transfer tracking data between space agencies facilitates the allocation of tracking sessions to
alternate antenna resources and increases the ability of space agencies to tolerate availability
issues with their primary antennas. The TDM supports the following types:
– ground-based radio metric types:
• uplink frequencies,
CCSDS 505.0-B-1 Page 2-1 December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
• downlink frequencies,
• range,
• Doppler,
• antenna angles,
• interferometric types;
– spacecraft-to-spacecraft Doppler and range; and
– ancillary information needed to calculate the measurement residuals, such as
meteorological data, media delays, and clock parameters.
The TDM is specified in reference [3].
2.2 EXTENSIBLE MARKUP LANGUAGE
2.2.1 GENERAL
This subsection briefly describes the Extensible Markup Language (XML), generalities of the
XML schema, and the justification for using XML for NDMs. XML schema structures and
data types are specified in references [4] and [5].
2.2.2 XML OVERVIEW
2.2.2.1 During the development of the ODM, it was determined that the specified Keyword
Value Notation (KVN) format was limited and that it was not necessarily well suited to cover
all possible needs of the NDMs. XML can be a much better form of specifying ASCII-based
data. This subsection presents a brief description of the broad features of XML.
2.2.2.2 XML is similar to the HyperText Markup Language (HTML) used for creating Web
pages, in that there are document tags (begin tags and end tags) that specify how to organize
the content. However, HTML has a fixed set of valid tags, while XML provides an
extensible framework that allows user-defined tag names that are structured according to the
logic of the particular application domain in which the document content exists. Additionally,
XML documents are required to be ‘well-formed’, whereas this restriction does not exist for
HTML documents. Discussion of the details of ‘well-formedness’ is beyond the scope of
this document, but it is essentially a set of rules that describe what constitutes a proper XML
document. If the rules are not followed, the document cannot be rendered correctly. HTML
is less strict.
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
2.2.2.3 Some of the advantages of using XML instead of standard ASCII text files for the
Navigation Data Messages application include:
– XML allows for the definition of the data message in a machine-readable format. The
format is basically a template called a ‘schema’. This schema can then be referred to
in the data file, and it can be used to verify that the data is compliant with the schema.
There are widely available programs to specify a schema, to assist with the processing
of XML data, and to automatically verify that the data messages comply with the
schema. Each participant in a data exchange can independently verify that the
message is compliant. This can simplify the development and validation of the
software used to write data in the proper format.
– XML defines standards for time formats and numerical values against which it is
possible to validate the contents of an XML field.
– XML allows for the nesting of data, so it is clear which metadata corresponds to
which data.
– XML allows for the specification of default and alternative attributes, such as units.
– XML allows for required and optional elements and attributes.
– XML allows for range checking and specification of lists of allowed values.
– XML allows for sharing elements between different specifications.
2.2.2.4 A few disadvantages of using XML for this application are:
– Tags are always duplicated, with the opening tag and the corresponding ending tag
making files bigger (in some cases it is possible that the byte count for tag
information exceeds the byte count of the actual data associated with the tags).
However, there are specific compressors for XML data (e.g., XMILL and XGRIND—
references [C5] and [C6]) that are much more efficient than those used for non-XML
formatted ASCII data.
– Some values can be specified as either attributes or child elements, so there could be
disagreement as to which method to use. This flexibility can also be seen as an
advantage, depending upon the application and the implementation.
– There are not many Flight Dynamics specialists that are skilled in XML.
2.2.3 JUSTIFICATION FOR USING XML SCHEMA
There are several ways in which XML files can be processed, for example: without
validation, with validation via Document Type Definition (DTD), with validation via
RELAX NG (reference [C7]), with validation via Schematron (reference [C8]), and with
validation via XML schema. In the case of the CCSDS, the CCSDS Management Council
CCSDS 505.0-B-1 Page 2-3 December 2010
XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
(CMC) has specified that the XML Schema method be used for XML validation. The
Navigation Working Group has therefore developed XML schema implementations for the
ODM, ADM and TDM Recommended Standards, consistent with the directive of the CMC.
These schema representations adopt the standard as approved by the World Wide Web
Consortium (W3C) (http://www.w3.org/).
2.2.4 JUSTIFICATION FOR INTEGRATED NDM/XML SCHEMA SET
There has been a movement towards the adoption of XML for space data systems data
interchange between agencies (e.g., the XML Telemetry and Command Exchange (XTCE)
developed by the Space Domain Task Force of the Object Management Group). Since there
are six separate NDM message types, some of which have considerable overlap in structure
and/or content, it is more efficient to structure the XML format for the set of NDMs into an
integrated set. This will help to ensure as much consistency and re-use as possible between
the message implementations, and facilitates the coding of programs that will produce the
messages that will be exchanged.
The integrated NDM/XML schema set will be stored in the CCSDS Space Assigned
Numbers Authority (SANA) repository, accessible by all interested parties. Via such an
arrangement, agencies creating instantiations of an NDM/XML schema will be able to
download the schema set from the CCSDS site to an operations server in their own agencies.
This will allow agencies to control the reliability and operations aspects of providing the
XML message types, and will ensure that all instantiations of an NDM/XML schema can be
validated in a consistent manner. Periodic updates of elements of the schema set could be
necessary in order to retain the correspondence to the KVN-formatted messages or to correct
errors in an individual schema, at which time agencies would download new copies of the
schema set. An agency that downloads a copy of the NDM/XML schema set to an operations
server under its management also has the option of introducing local modifications to the
schema set, though doing so could diminish its utility as an interagency exchange medium.
2.3 SPECIAL CONSIDERATIONS
2.3.1 COMMENTS IN NDM/XML INSTANTIATIONS
Each of the KVN format NDMs provides a ‘COMMENT’ keyword that is used for a variety
of documentation purposes. In most cases the individual messages are consistent with
respect to the use of comments, and the placement is the same in the KVN and XML
versions. However, for historical reasons, in the original issue of the ODM
Recommendation, the allowed placement of comments was much freer than in subsequent
Recommendations of the Navigation Working Group. Allowing complete freedom in the
placement of comments in a KVN document is not problematic, however, an XML schema

CCSDS Management Council Resolution MC-F02-09 directed Subpanel P1J (precursor to Navigation
Working Group) to utilize PVL, or preferably XML schema language, in the CCSDS 502.0-R-2 Orbit Data
Messages.
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
supporting such free placement of comments has some difficulties. For example, it could
become impossible to convert between the XML and text versions of a message in a way that
comments can be uniquely associated to the proper data elements. Allowing comments
anywhere also makes a schema overly complex, lengthy, and error prone; obscures the
meaningful structure of the schema; and in some cases makes it impossible for it to be
correctly interpreted by XML validators. For these reasons, the elements of the schema set
corresponding to the original issue of the ODM restrict the placement of comments.
2.3.2 DISCUSSION OF ‘VALIDATION CHECKING’
There are some elements in the ADM, ODM, and TDM that have structure for which
checking could be performed, but is not done in the NDM XML schema set. Specifically,
time systems, object names, reference frames, and center names could be defined by an
enumerated list, and object IDs could be defined via a matching pattern. However, it has
been decided not to enforce these potential restrictions and to allow a generic string to be
used for the values associated with these concepts. In future versions of the ADM, ODM,
and TDM, there could be some validation checking imposed based on the requirement to
include ‘normative references’ that specifically enumerate the acceptable values for some
metadata keywords.
Because of this validation checking convention, the user of one of the messages will be
responsible for more validation code at the application level than would be necessary if strict
checking and validation were performed at the schema level (for example, if
UVC is coded, then user code will need to determine
that ‘UVC’ is not a valid value for the time system).

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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
3 BASIC STRUCTURE OF THE NDM/XML SCHEMA SET
3.1 NAVIGATION DATA MESSAGES AND THE ASSOCIATED SCHEMA SET
3.1.1 The basic element in the NDM/XML is a Navigation Data Message (NDM). An
‘NDM’ shall consist of at least one of the following messages:
– Attitude Parameter Message (APM, reference [1], section 3);
– Attitude Ephemeris Message (AEM, reference [1], section 4);
– Orbit Parameter Message (OPM, reference [2], section 3);
– Orbit Mean Elements Message (OMM, reference [2], section 4);
– Orbit Ephemeris Message (OEM, reference [2], section 5);
– Tracking Data Message (TDM, reference [3], section 3).
3.1.2 The NDM/XML schema set shall consist of a schema for each Blue Book version of
each individual message type, an ‘NDM combined instantiation’ schema, a namespace
schema, and a master validator schema. A schema containing elements common to more
than one Navigation Working Group schema and a schema containing elements that are
potentially common across more than one CCSDS application complete the current schema
set, yielding a schema set with a total of 11 members (see table 3-1).
3.1.3 The NDM/XML schema set shall be available on a CCSDS resource that is internet
accessible.
NOTE – The NDM/XML schema set is currently available at:
http://sanaregistry.org/r/ndmxml/[schemaName]
3.1.4 For schemas directly associated with one of the NDM message types, the components
of [schemaName] shall be
ndmxml-[ndmxmlVersionNumber]-[messageType]-[blueBookNumber].xsd
where
– [ndmxmlVersionNumber] is 1.0
– [messageType] is one of the set {aem, apm, oem, omm, opm, tdm}
– [blueBookNumber] is the Blue Book version of the respective message (e.g., ‘1.0’ for
the AEM and APM)
In this document, ‘Blue Book version’ is synonymous with ‘Blue Book issue’.
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XML SPECIFICATION FOR NAVIGATION DATA MESSAGES
NOTES
1 There are also several test files and example NDM/XML instantiations on the CCSDS
Web site.
2 The following table illustrates the naming convention in the names of the NDM/XML
schema set. The ‘Blue Book Supported’ column indicates the messages and
respective Blue Books to which the schema applies.
3 Special considerations apply to instantiations that are compatible with the ODM Issue
1.0 Silver Book. These are described in the portions of section 4 that address
instantiations of the OEM and OPM.
4 The naming convention for the auxiliary schemas not directly associated with an
NDM (common, master, namespace) is similar to the convention for the message-
related schemas, but not identical.
Table 3-1: The NDM/XML Schema Set
Schema Blue Book Supported
ndmxml-1.0-aem-1.0.xsd ADM Attitude Ephemeris Message (Blue 1.0).
ndmxml-1.0-apm-1.0.xsd ADM Attitude Parameter Message (Blue 1.0).
ndmxml-1.0-oem-2.0.xsd ODM Orbit Ephemeris Message (Blue 2.0).
ndmxml-1.0-omm-2.0.xsd ODM Orbit Mean Elements Message (Blue 2.0).
ndmxml-1.0-opm-2.0.xsd ODM Orbit Parameter Message (Blue 2.0).
ndmxml-1.0-tdm-1.0.xsd TDM Tracking Data Message (Blue 1.0).
ndmxml-1.0-navwg-common.xsd Constructs unique to Navigation Working Group used in
more than one schema in the NDM schema set. ADM
1.0, ODM 2.0, TDM 1.0.
ndmxml-1.0-ccsds-common.xsd Constructs that could in principle be used across the
CCSDS domain. ADM 1.0, ODM 2.0, TDM 1.0.
ndmxml-1.0-ndm-1.0.xsd NDM combined instantiation schema, used where it is
desired to exchange multiple related constituent NDMs.
ADM 1.0, ODM 2.0, TDM 1.0.
ndmxml-1.0-namespace.xsd Schema that includes each element of the NDM XML
schema set. AD
...