RECOMMENDATION FOR SPACE
DATA SYSTEM STANDARDS
ORBIT DATA MESSAGESCCSDS 502.0-R-3 (Draft 6)
Draft RED BOOK
March 2003
CCSDS RECOMMENDATION FOR ORBIT DATA MESSAGES
AUTHORITY
Issue: / Red Book, Issue 3 (Draft 6)Date: / March 2003
Location: / n/a
(WHEN THIS RECOMMENDATION IS FINALIZED, IT WILL CONTAIN THE FOLLOWING STATEMENT OF AUTHORITY:)
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 Recommendations 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 Recommendation is published and maintained by:
CCSDS Secretariat
Program Integration Division (Code MT)
National Aeronautics and Space Administration
Washington, DC 20546, USA
FOREWORD
(WHEN THIS RECOMMENDATION IS FINALIZED, IT WILL CONTAIN THE FOLLOWING FOREWORD:)
This document is a technical Recommendation for orbit data messages and has been prepared by the Consultative Committee for Space Data Systems (CCSDS). The set of orbit data messages described in this Recommendation is the baseline concept for trajectory representation in data interchange applications that are cross-supported between Agencies of the CCSDS.
This Recommendation establishes a common framework and provides a common basis for the interchange of orbit data. 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 Recommendation and may incorporate features not addressed by this Recommendation.
Through the process of normal evolution, it is expected that expansion, deletion or modification to this document may occur. This Recommendation is therefore subject to CCSDS document management and change control procedures, as 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.
At time of publication, the active Member and Observer Agencies of the CCSDS were:
Member Agencies
– Agenzia Spaziale Italiana (ASI)/Italy.
– British National Space Centre (BNSC)/United Kingdom.
– Canadian Space Agency (CSA)/Canada.
– Centre National d’Etudes Spatiales (CNES)/France.
– Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)/Germany.
– European Space Agency (ESA)/Europe.
– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.
– National Aeronautics and Space Administration (NASA)/USA.
– National Space Development Agency of Japan (NASDA)/Japan.
– Russian Space Agency (RSA)/Russian Federation.
Observer Agencies
– Austrian Space Agency (ASA)/Austria.
– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.
– Centro Tecnico Aeroespacial (CTA)/Brazil.
– Chinese Academy of Space Technology (CAST)/China.
– Commonwealth Scientific and Industrial Research Organization (CSIRO)/Australia.
– Communications Research Centre (CRC)/Canada.
– Communications Research Laboratory (CRL)/Japan.
– Danish Space Research Institute (DSRI)/Denmark.
– European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)/Europe.
– European Telecommunications Satellite Organization (EUTELSAT)/Europe.
– Federal Service of Scientific, Technical & Cultural Affairs (FSST&CA)/Belgium.
– Hellenic National Space Committee (HNSC)/Greece.
– Indian Space Research Organization (ISRO)/India.
– Institute of Space and Astronautical Science (ISAS)/Japan.
– Institute of Space Research (IKI)/Russian Federation.
– KFKI Research Institute for Particle & Nuclear Physics (KFKI)/Hungary.
– MIKOMTEK: CSIR (CSIR)/Republic of South Africa.
– Korea Aerospace Research Institute (KARI)/Korea.
– Ministry of Communications (MOC)/Israel.
– National Oceanic & Atmospheric Administration (NOAA)/USA.
– National Space Program Office (NSPO)/Taipei.
– Swedish Space Corporation (SSC)/Sweden.
– United States Geological Survey (USGS)/USA.
PREFACE
This document is a draft CCSDS Recommendation. Its ‘Red Book” status indicates that the CCSDS believes the document to be technically mature and has released it for formal review by appropriate technical organizations. As such, its technical content is not stable and several iterations of it may occur in response to comments received during the review process. Implementers are cautioned not to fabricate any final equipment in accordance with this document’s technical content.
DOCUMENT CONTROL
Document / Title and Issue / Date / StatusCCSDS 502.0-R-1 / Orbit Data Messages,
Issue 1 / June 2001 / Original Issue
CCSDS 502.0-R-2 / Orbit Data Messages,
Issue 2 / April 2002 / Second Issue
Extensive changes throughout based on P1J review and initial RIDs
CCSDS 502.0-R-3
(Draft) / Orbit Data Messages,
Issue 3 (Draft 3) / November 2002 / Draft Third Issue
Further extensive changes based on additional RIDs from full CCSDS review
CCSDS 502.0-R-4
3 (Draft 4) / Orbit Data Messages,
Issue 3 (Draft 4) / January 2003 / Draft Third Issue
Additional changes based on more RIDS and further P1J review.
CCSDS 502.0-R-5
3 (Draft 5) / Orbit Data Messages,
Issue 3 (Draft 5) / January 2003 / Draft Third Issue
Separation of syntax and semantics
CCSDS 502.0-R-3 (Draft 6) / Orbit Data Messages,
Issue 3 (Draft 6) / March 2003 / Draft Third Issue
Separation of syntax and semantics
CONTENTS
Section Page
1 INTRODUCTION 1-1
1.1 PURPOSE 1-1
1.2 Scope and APPLICABILITY 1-1
1.3 References 1-1
2 Overview 2-1
2.1 Orbit Data MESSAGES 2-1
2.2 MEssage Exchange 2-2
2.3 reference for DEFINITIONS 2-2
3 ORBIT PARAMETER MESSAGE (OPM) Semantics 3-1
3.1 OPM HEADER KEYWORD SET 3-1
3.2 OPM BODY KEYWORD SET 3-1
3.3 OPM DATA 3-3
3.4 COMMENTS IN AN OPM 3-6
4 EPHEMERIS MESSAGE (EPM) SEMANTICS 4-1
4.1 EPM HEADER KEYWORD SET 4-1
4.2 EPM METADATA KEYWORD SET 4-1
4.3 EPM EPHEMERIS DATA 4-4
4.4 COMMENTS 4-4
5 ORBIT DATA MESSAGE ASCII FILE SYNTAX 5-6
5.1 ODM ACII FILE SYNTAX 5-6
5.2 OPM KEYWORD SET and Statement ordering 5-8
5.3 EPM KEYWORD SET and Statement ordering 5-11
5.4 ASCII FILE Examples 5-13
ANNEX A RATIONALE FOR ORBIT DATA MESSAGES 5-1
ANNEX B ABBREVIATIONS AND ACRONYMS 5-6
CONTENTS (continued)
Figures Page
5-1 OPM File Example Using Comments to Denote Updates in ASCII File Format 5-13
5-2 OPM File Example with Optional Keplerian Elements and Two Maneuvers in ASCII File Format 5-14
5-3 EPM Example in ASCII File Format 5-15
Tables
3-1 OPM Header Description 3-1
3-2 OPM Keyword Descriptions 3-3
4-2 EPM Header Description 4-1
4-3 EPM Metadata Keywords 4-3
5-1 OPM Keyword Ordering and Keyword to Data Entity Mapping 5-10
A-1 Primary Requirements 5-2
A-2 Heritage Requirements 5-3
A-3 Desirable Characteristics 5-3
A-4 Applicability of the Criteria to Orbit Data Codes 5-4
A-5 Services Available with Orbit Data Codes 5-4
CCSDS 502.0-R-3 Page 2-1 February 2003
CCSDS RECOMMENDATION FOR ORBIT DATA MESSAGES
1 INTRODUCTION
1.1 PURPOSE
This Orbit Data Message (ODM) Recommendation specifies two standards for use in transferring spacecraft orbit information between Member Agencies. Such exchanges are used for (1) pre-flight planning for tracking or navigation support, (2) scheduling tracking support, (3) carrying out tracking operations (sometimes called metric predicts), and (4) orbit comparisons.
This Recommendation does not address precision and accuracy of the derived spacecraft position and velocity.
This Recommendation includes sets of requirements and criteria that the message formats have been designed to meet. For exchanges where the existing requirements do not capture the needs of the participating agencies, the participating agencies may agree to use another mechanism for that particular exchange.
This Recommendation defines the ODM Data Dictionary and specifies syntactical codings. These syntactical codings do not preclude future definitions of other syntactical codings that conform to the data dictionary.
1.2 Scope and APPLICABILITY
This Recommendation contains two orbit data messages standards designed for applications involving data interchange in space data systems. The rationale behind the design of each message is described in Annex A and may help the application engineer select a suitable message. Definition of the orbit accuracy underlying a particular orbit message is outside the scope of the Recommendation. Applicability information specific to each orbit data message format appears in Sections 3 and 4, and in Appendix A3.
1.3 References
The following documents contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All documents are subject to revision, and users of this Recommendation 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 Recommendations.
[1] Navigation Data—Definitions and Conventions. Report Concerning Space Data System Standards, CCSDS 500.0-G-1. Green Book. Issue 1. Washington, D.C.: CCSDS, June 2001. [ http://www.ccsds.org/
[2] Spacewarn Bulletin. Greenbelt, MD, USA: World Data Center for Satellite Information: WDC-SI. [ http://nssdc.gsfc.nasa.gov/spacewarn ]
[3] Standard Frequencies and Time Signals. Volume 7 of Recommendations and Reports of the CCIR: XVth Plenary Assembly. Geneva: CCIR, 1982.
[4] Information Technology—8-Bit Single-Byte Coded Graphic Character Sets—Part 1: Latin Alphabet No. 1. International Standard, ISO/IEC 8859-1:1998. Geneva: ISO, 1998. [ http://www.iso.ch ]
CCSDS 502.0-R-3 Page 2-1 February 2003
CCSDS RECOMMENDATION FOR ORBIT DATA MESSAGES
2 Overview
2.1 Orbit Data MESSAGES
Two CCSDS-recommended orbit data messages are described: the Orbit Parameter Message (OPM) and the Ephemeris Message (EPM).
2.1.1 Orbit Parameter Message (OPM)
An Orbit Parameter Message (OPM) is a description of the position and velocity of a single object at a specified epoch.
Orbit information may be exchanged between two participants by sending a state vector (see reference [1]) for a specified epoch using an OPM. The message receiver site must have an orbit propagator available that is able to propagate the OPM state vector to compute the position and velocity at times different from the specified epoch. For this propagation, additional ancillary information (spacecraft properties such as mass, area, and maneuver planning data, if applicable) is to be included with the message.
The OPM is suited to inter-agency exchanges that (1) involve automated interaction and/or human interaction and (2) do not require high-fidelity dynamic modeling.
The use of the OPM is applicable under the following conditions.
a) an orbit propagator is run at the receiver’s site;
b) the receiver’s modeling of gravitational forces, central body rotation, solar radiation pressure, atmospheric drag and thrust phases (see reference [1]) must fulfill accuracy requirements established between the agencies.
It is desirable for the OPM to be easily readable by both humans and computers.
The OPM is fully self-contained; no additional information is required.
2.1.2 Ephemeris Message (EPM)
An EPM is a representation of the position and velocity of a single object over a specified time range.
The EPM is suited to inter-agency exchanges that (1) involve automated interaction and (2) require high-fidelity dynamic modeling.
The EPM requires the use of an interpolation technique to interpret the position and velocity at times different from the included epochs.
It is desirable for the EPM to be easily readable by both humans and computers.
The EPM is fully self-contained; no additional information is required.
2.2 MEssage Exchange
Naming specifications for message exchanges shall be agreed to on a case-by-case basis between the participating agencies, typically using an Interface Control Document.
Multiple OPM or EPM messages may be provided in exchanges for a given object to achieve ephemeris fidelity requirements.
2.3 reference for DEFINITIONS
Definitions of time systems, reference frames and planetary models are provided in Reference 1 and in references given in Reference 1.
(TBD - Is it clear to others exactly which definitions are being picked up here? Should we note exactly which terms from reference 1 are used in this document? Should the definitions be moved here instead of being in a GB? Remember GB can be changed without a formal agency reviews and approvals. On the other hand, reference indicates which version. But CCSDS does not make old versions of GBs available.)
CCSDS 502.0-R-3 Page 2-1 February 2003
CCSDS RECOMMENDATION FOR ORBIT DATA MESSAGES
3 ORBIT PARAMETER MESSAGE (OPM) Semantics
3.1 OPM HEADER KEYWORD SET
3.1.1 The first header line must be the first non-blank line in the file. (Syntax)
Only those keywords shown in tables 31 are allowed. They are obligatory.
Only those units specified in table 3-2 are allowed. (Body Information not Header, Moved to 3.2.1)
The header shall provide a CCSDS Orbit Data Message version number that identifies the format version; this is included to anticipate future changes. The version keyword is CCSDS_OPM_VERS and the value shall have the form of x.y where y is incremented for corrections and minor changes, and x is incremented for major changes. The initial version shall be 1.0.
3.1.2 The header shall include the CREATION_DATE keyword with the value set to the Coordinated Universal Time (UTC) the file was created, using the ISO standard. A description of OPM header items and values is provided in table 3-1.
Keyword / Description / Examples of Values / ObligatoryCCSDS_OPM_VERS / Format version / 1.0 / Yes
CREATION_DATE / File creation date and time / 2001-11-06T11:17:33
2002-204T15:56:23 / Yes
Table 31: OPM Header Description
3.2 OPM BODY KEYWORD SET
3.2.1 Excepting In addition to the header items described in Table 3-1, the KVN assignments used in an OPM file shall be those given in Table 3-2, which specifies for each item (1) its required sequence of occurrence in the OPM file, (2) the keyword to be used, (3) a short description of the item, (4) the required units, if applicable, and (5) whether the item is obligatory or optional. Only those keywords shown are allowed. (Note: (1) and (2) are really Syntax)
Only the units specified in Table 3-2 are allowed.
Keyword / Description / Units / ObligatoryGeneral Information
OBJECT_NAME / Object Name / n/a / Yes
OBJECT_ID / Object International ID Specification / n/a / Yes
CENTER_NAME / Reference Frame Center Location / n/a / Yes
REF_FRAME / Reference Frame Name / n/a / Yes
TIME_SYSTEM / Time System Representation / n/a / Yes
EPOCH / State Vector Epoch / n/a / Yes
State Vector Components in the Specified Coordinate System
X / Position vector X-component / KM / Yes
Y / Position vector Y-component / KM / Yes
Z / Position vector Z-component / KM / Yes
X_DOT / Velocity vector X-component / KM/S / Yes
Y_DOT / Velocity vector Y-component / KM/S / Yes
Z_DOT / Velocity vector Z-component / KM/S / Yes
Keplerian Elements in the Specified Reference Frame (None or all parameters of this block are to be given.)
SEMI_MAJOR_AXIS / Semi-major axis / KM / No
ECCENTRICITY / Eccentricity / n/a / No
INCLINATION / Inclination / DEG / No
RA_OF_ASC_NODE / Right Ascension of ascending node / DEG / No
ARG_OF_PERICENTER / Argument of pericenter / DEG / No
TRUE_ANOMALY or MEAN_ANOMALY / True anomaly or mean anomaly / DEG / No
GM / Gravitational Coefficient / KM**3/
S**2 / No
Spacecraft Parameters
MASS / S/C Mass at Epoch / KG / Yes
SOLAR_RAD_AREA / Solar Radiation Pressure Area (AR). / M**2 / Yes
SOLAR_RAD_COEFF / Solar Radiation Pressure Coefficient (CR). / n/a / Yes
DRAG_AREA / Drag Area (AD). / M**2 / Yes
DRAG_COEFF / Drag Coefficient (CD). / n/a / Yes
Maneuver Parameters (Repeat for each maneuver. None or all parameters of this block are to be given.)
MAN_EPOCH_IGNITION / Epoch of ignition / v / No
MAN_DURATION / Maneuver duration / S / No
MAN_DELTA_MASS / Mass change during maneuver (value is < 0) / KG / No
MAN_REF_FRAME / Coordinate system for velocity increment vector / n/a / No
MAN_DV_1 / 1st component of the velocity increment / KM/S / No
MAN_DV_2 / 2nd component of the velocity increment / KM/S / No
MAN_DV_3 / 3rd component of the velocity increment / KM/S / No
Comments (Allowed everywhere in the message after the OPM version no.)
COMMENT / Each comment line has to begin with this keyword. / n/a / No
Table 32: OPM Keyword Descriptions