BS EN 16603-10-09:2014 BSI Standards Publication Space engineering — Reference coordinate system BS EN 16603-10-09:2014 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 16603-10-09:2014 The UK participation in its preparation was entrusted to Technical Committee ACE/68, Space systems and operations A list of organizations represented on this committee can be obtained on request to its secretary This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application © The British Standards Institution 2014 Published by BSI Standards Limited 2014 ISBN 978 580 83407 ICS 49.140 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2014 Amendments/corrigenda issued since publication Date Text affected BS EN 16603-10-09:2014 EN 16603-10-09 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM July 2014 ICS 49.140 English version Space engineering - Reference coordinate system Ingéniérie spatiale - Système de coordonnées de référence Raumfahrttechnik - Bezugskoordinatensystem This European Standard was approved by CEN on 28 December 2013 CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN and CENELEC member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels © 2014 CEN/CENELEC All rights of exploitation in any form and by any means reserved worldwide for CEN national Members and for CENELEC Members Ref No EN 16603-10-09:2014 E BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Table of contents Foreword Introduction Scope Normative references Terms, definitions and abbreviated terms 3.1 Terms from other standards 3.2 Terms specific to the present standard .9 3.3 Abbreviated terms 10 Objectives, process and principles 12 4.1 General 12 4.2 Concepts and processes 12 4.3 4.2.1 Process .12 4.2.2 Documentation 12 4.2.3 Coordinate system chain analysis 12 4.2.4 Notation 13 Technical issues .13 4.3.1 Frame and coordinate system 13 4.3.2 Transformation between coordinate systems 13 4.3.3 IERS definition of a transformation 14 4.3.4 Time 14 Requirements 15 5.1 Overview 15 5.2 Process requirements .15 5.3 5.2.1 Responsibility 15 5.2.2 Documentation 15 5.2.3 Analysis 16 General requirements .16 5.3.1 Applicability .16 5.3.2 Notation 17 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) 5.3.3 5.4 Figures 17 Technical requirements 18 5.4.1 Frame .18 5.4.2 Coordinate system 18 5.4.3 Unit 18 5.4.4 Time 18 5.4.5 Mechanical frames 19 5.4.6 Planet coordinates 19 5.4.7 Coordinate system parameterisation 19 5.4.8 Transformation decomposition and parameterisation 19 5.4.9 Transformation definition 20 Annex A (normative) Coordinate Systems Document (CSD) - DRD 22 A.1 A.2 DRD identification 22 A.1.1 Requirement identification and source document 22 A.1.2 Purpose and objective .22 Expected response 22 A.2.1 Scope and content 22 A.2.2 Special remarks 24 Annex B (informative) Transformation tree analysis 25 B.1 General 25 B.2 Transformation examples .25 B.3 Tree analysis 25 B.4 Franck diagrams .25 Annex C (informative) International standards authorities 32 C.1 Standards .32 C.2 Time .32 C.3 C.4 C.2.1 United States Naval Observatory (USNO) 32 C.2.2 Bureau International des Poids et Mesures (BIPM) 32 Ephemerides 32 C.3.1 Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE) 32 C.3.2 Jet Propulsion Laboratory (JPL) ephemerides 33 Reference systems 33 C.4.1 International Earth Rotation and Reference Systems Service (IERS) 33 C.4.2 International Astronomical Union (IAU) 33 C.4.3 United States naval observatory (USNO) 33 C.4.4 National Imagery and Mapping Agency (NIMA) 34 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) C.5 C.6 Consultative Committee for Space Data Systems (CCSDS) 34 C.5.1 Navigation 34 C.5.2 Orbit 34 C.5.3 Attitude 34 IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements (WGCCRE) .35 References 36 Bibliography 37 Figures Figure B-1 : General tree structure illustrating a product tree 28 Figure B-2 : Transformation chain decomposition for coordinate systems 29 Figure B-3 : Example of Franck diagram for a spacecraft 30 Figure B-4 : Example of Franck diagram for a star tracker 31 Tables Table B-1 : Example of mechanical body frame 26 Table B-2 : Example of orbital coordinate system 27 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Foreword This document (EN 16603-10-09:2014) has been prepared by Technical Committee CEN/CLC/TC “Space”, the secretariat of which is held by DIN This standard (EN 16603-10-09:2014) originates from ECSS-E-ST-10-09C This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2015, and conflicting national standards shall be withdrawn at the latest by January 2015 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights This document has been developed to cover specifically space systems and has therefore precedence over any EN covering the same scope but with a wider domain of applicability (e.g : aerospace) According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.” BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Introduction Clear definition of reference directions, coordinate systems and their interrelationships is part of the System Engineering process Problems caused by inadequate early definition, often pass unnoticed during the exchange of technical information This Standard addresses this by separating the technical aspects from the issues connected with process, maintenance and transfer of such information Clause provides some explanation and justification, applicable to all types of space systems, missions and phases Clause contains the requirements and recommendations Helpful and informative material is provided in the Annexes BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Scope The objective of the Coordinate Systems Standard is to define the requirements related to the various coordinate systems, as well as their related mutual interrelationships and transformations, which are used for mission definition, engineering, verification, operations and output data processing of a space system and its elements This Standard aims at providing a practical, space-focused implementation of Coordinate Systems, developing a set of definitions and requirements These constitute a common reference or “checklist” of maximum utility for organising and conducting the system engineering activities of a space system project or for participating as customer or supplier at any level of system decomposition This standard may be tailored for the specific characteristics and constraints of a space project in conformance with ECSS-S-ST-00 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this ECSS Standard For dated references, subsequent amendments to, or revisions of any of these publications, not apply However, parties to agreements based on this ECSS Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below For undated references the latest edition of the publication referred to applies EN reference Reference in text Title EN 16601-00-01 ECSS-S-ST-00-01 ECSS system– Glossary of terms EN 16601-10 ECSS-M-ST-10 Space project management – Project planning and implementation BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) are docked together Additional arrows (broken lines) can be added to indicate measurement or estimation Figure B-3 shows a Franck diagram for a spacecraft, whilst Figure B-4 shows a preliminary Franck diagram for star tracker alignment Table B-1: Example of mechanical body frame TYPE : Title/Name : Mnemonic : ID : Spacecraft fixed Attitude control frame CONT S/C-CONT-01 Definition : Origin at spacecraft centre of mass Axes parallel to the Mechanical Reference Frame (MRF) axes and with the same sign Rationale : The coordinates of a point in S/C-MRF-01 are related its coordinates in S/C-CONT-01 Transformation : from MRF, S/C-MRF-01 Translation : defined by the coordinates of the centre of mass of the spacecraft in MRF Rotation : none Order : not applicable Comments/limitations : This centre of mass frame is applicable for the idealised case of a rigid body The null rotation is included here explicitly, as an example In general, it may take other values Formula : Translation Diagram: X Y = Z MRF Rotation X COM Y + COM Z COM MRF 1 0 X 0 × Y 0 1 Z CONT ZCONT YCONT XCONT ZMRF YMRF 26 XMRF BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Table B-2: Example of orbital coordinate system TYPE : Title/Name : Mnemonic : ID : Pseudo-inertial Equatorial coordinate frame E IN-E-01 Definition : Origin is at the centre of the Earth The X axis lies in the equatorial plane and passes through the intersection of the equator with the meridian line at Kourou longitude The Z axis is the rotation axis of the Earth The Y axis completes the right handed triad Rationale : The equatorial coordinate frame is used to depict the trajectory of the launcher from Earth to Orbit Navigation and Guidance data (position, velocity and attitude) may be provided in this frame Transformation : from True of Date frame (TOD), IN-TOD-01 Translation : none Rotation : defined by the following matrix M E 2TOD cos(θ E 2TOD ) sin(θ E 2TOD ) 0 = − sin(θ E 2TOD ) cos(θ E 2TOD ) 0 0 1 where θ E 2TOD is the angle (in radians) between the X axis of the equatorial coordinate frame and the true line of equinox directed towards the Sun at the vernal equinox Order : not applicable Comments/limitations : This equatorial frame is frozen at a given time Formula : Translation X Y = Z TOD Rotation X 0 0 + M E 2TOD × Y Z E 0 TOD 27 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Diagram : ZE θE2TOD Kouro YE O Vernal direction XE Level-0 Level-0 reference coordinate system kinetic trans- Level-1 Level-1 coordinate system Level-2 coordinate system Level-2 coordinate system kinetic trans- kinetic trans- Level-3 coordinate system Figure B-1: General tree structure illustrating a product tree 28 Level-3 Level-3 coordinate system kinetic trans- Level-2 kinetic trans- kinetic trans- BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Application to Planet reference coordinate system kinetic transformation planetary coordinate system Basic etc moving system coordinate system intermediate coordinate system etc Application to Vehicle vehicle coordinate system etc NOTE kinetic transformation mobile equipment or fixed instrument etc etc A kinetic transformation can have some fixed or constrained degrees of freedom (DoF) Figure B-2: Transformation chain decomposition for coordinate systems 29 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) ToD frame trajectory local orbital frame T, R attitude guidance frame attitude mechanical reference frame T, R attitude control frame T, R Sun sensor measurement frame Static transformations T = translational transformation R = rotational transformation Dynamic transformations vehicle trajectory/orbit vehicle attitude Figure B-3: Example of Franck diagram for a spacecraft 30 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) determine T,R measure T,R T,R STR alignment frame Level-1 STR mechanical reference frame s/c alignment frame Level-0 s/c mechanical reference frame T,R Level-2 STR boresight reference frame Quaternion of boresight reference frame w.r.t star catalogue frame Figure B-4: Example of Franck diagram for a star tracker 31 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Annex C (informative) International standards authorities C.1 Standards The international authorities listed below define and maintain reference information C.2 Time C.2.1 United States Naval Observatory (USNO) The Official Source of Time for the Department of Defense (DoD) and for the Global Positioning System (GPS), as well as a Standard of Time for the United States See for a concise summary of the definitions of time, e.g Terrestrial Time (TT) C.2.2 Bureau International des Poids et Mesures (BIPM) The task of the BIPM is to ensure world-wide uniformity of measurements and their traceability to the International System of Units (SI) See The link to time information and link to the ftp server is Click on “Circular T” for information on TAI and UTC Data for calculating TAI are available at C.3 Ephemerides C.3.1 Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE) The ephemerides of the planets and bodies of the solar system are produced at the IMCCE See 32 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Information on direct link to solar system ephemeris data is available at: and C.3.2 Jet Propulsion Laboratory (JPL) ephemerides Jet Propulsion Laboratory (JPL) provides ephemerides for planets, planetary satellites, comets and asteroids in the DExxx frame The Moon ephemeris is in the LExxx frame In addition, tools are provided for the correct interpretation of the data See C.4 Reference systems C.4.1 International Earth Rotation and Reference Systems Service (IERS) The IERS realises the definition, models and procedures for standard reference systems These are based on resolutions of international scientific unions, such as the IAU and the IUGG They include the celestial system, the terrestrial system, the transformation between the celestial and terrestrial systems, definition of time coordinates and time transformations, models of light propagation and motion of massive bodies See See for Technical Note 32 [2], which is updated regularly by the IERS to account for geophysical modifications Chapters and treat the ICRS and ITRS, whilst chapter provides the transformation from the celestial frame to a conventional terrestrial frame Many ftp-links are provided for maintained software C.4.2 International Astronomical Union (IAU) The IAU deals with all Solar system objects, whereas the IERS is concerned more specifically with the Earth See The ICRS for the solar system and for the Earth are called the Barycentric Celestial Reference System (BCRS) and the Geocentric Celestial Reference System (GCRS) respectively, each having a “non-rotating” origin C.4.3 United States naval observatory (USNO) The USNO also provides FORTRAN routines and data for the transformation between ITRS and GCRS See At , it is possible to get a snapshot definition of time and access the Earth rotation parameters, which are essential 33 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) for the transformation between Earth-centred inertial coordinates and Earthcentred Earth-fixed coordinates It is also possible to obtain IERS bulletins A, B and C automatically, by email C.4.4 National Imagery and Mapping Agency (NIMA) The world geodetic system, WGS84 (valid until 2010), defines Earth reference frames for use in geodesy and navigation Though rather old, it is used for GPS It provides the most accurate geodetic and gravitational data and local datum transformation constants and formulae for transforming different data into WGS84, see C.5 Consultative Committee for Space Data Systems (CCSDS) C.5.1 Navigation Navigation data – definitions and conventions, informational report CCSDS 500.0-G-2, Green book, November 2005, see Spacecraft navigation data are exchanged between CCSDS member agencies during cross support of space missions The Green Book establishes a common understanding for the exchange of navigation data It includes orientation and manoeuvre information as part of the spacecraft navigation process See chapter for coordinate frame identification, time and astrodynamic constants C.5.2 Orbit Orbit data messages – CCSDS 502.0-B-1, Blue book, September 2004, see This recommendation specifies two standard message formats for use in transferring spacecraft orbit information between space agencies: the orbit parameter message and the orbit ephemeris message The document includes sets of requirements and criteria that the message formats have been designed to meet Another mechanism may be selected for exchanges where these requirements not capture the needs of the participating agencies C.5.3 Attitude Attitude data messages – CCSDS 504.0-B-1, Blue book, see This document specifies two types of standard attitude data message formats for use in transferring spacecraft attitude information between space agencies: the attitude parameter message and the attitude ephemeris message 34 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) C.6 IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements (WGCCRE) The WGCCRE issues a report, following three-yearly IAU meetings, describing the currently recommended models for the cartographic coordinates and rotational elements of all solar system bodies See 35 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) References 36 [1] “The past, present and future of reference systems for astronomy and geodesy”, G.A Wilkins, Proceedings of the 141st symposium on the International Astronomical Union, Leningrad, October 17-21, 1989, (Kluwer academic publishers), pp 39-46 [2] IERS Technical Note 32 “IERS conventions (2003)”, D.D McCarthy and G Petit (eds.), US Naval Observatory (USNO) and Bureau International des Poids et Mesures (BIPM), 2004 [3] “ESA Pointing Error Handbook”, ESA-NCR-502, 19 February 1993 [4] “Guide to the expression of uncertainty in measurement”, ISO et al 1995 BS EN 16603-10-09:2014 EN 16603-10-09:2014 (E) Bibliography EN reference Reference in text Title EN 16601-00 ECSS-S-ST-00 ECSS system – Description and implementation EN 16603-10 ECSS-E-ST-10 Space engineering – System engineering general requirements 37 This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and other standardization products are published by BSI Standards Limited About us Revisions We bring together business, 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