SIST EN 16603-60-30:2015
(Main)Space engineering - Satellite AOCS requirements
Space engineering - Satellite AOCS requirements
This Standard specifies a baseline for the attitude and orbit control system requirements to be used in the Project Requirements Document for space applications.
Project requirements documents are included in business agreements, which are agreed between the parties and binding them, at any level of space programmes, as described in ECSS-S-ST-00.
This Standard deals with the attitude and orbit control systems developed as part of a satellite space project. The classical attitude and orbit control systems considered here include the following functions:
• Attitude estimation
• Attitude guidance
• Attitude control
• Orbit control
• Orbit estimation, called Navigation in this document, can be part of the function for missions which explicitly require this function
• Acquisition and maintenance of a safe attitude in emergency cases and return to nominal mission upon command
The present Standard does not cover missions that include the following functions:
• Real-time on-board trajectory guidance and control
• Real-time on-board relative position estimation and control
Example of such missions are rendezvous, formation flying, launch vehicles and interplanetary vehicles.
Although the present document does not cover the above mentioned types of mission, it can be used as a reference document for them.
This standard may be tailored for the specific characteristic and constraints of a space project in conformance with ECSS-S-ST-00.
Raumfahrttechnik - Anforderungen an Satelliten-AOCS
Ingénierie spatiale - Exigences pour le système de contrôle d'attitude et d'orbite d'un satellite
Vesoljska tehnika - Zahteve za satelitski AOCS (sistem obvladovanja orbitalne lege /satelita/)
Ta standard določa osnovo za zahteve za sistem obvladovanja orbitalne lege/satelita, ki se uporabljajo v dokumentu projektnih zahtev za vesoljske aplikacije. Dokumenti projektnih zahtev so vključeni v poslovne dogovore med strankami z zavezami na kateri koli ravni vesoljskih programov, kot je opisano v standardu ECSS-S-ST-00, in jih zavezujejo. Ta standard obravnava sisteme obvladovanja orbitalne lege/satelita, razvite kot del vesoljskega projekta za satelit. Standardni sistemi obvladovanja orbitalne lege/satelita, obravnavani v tem dokumentu, vključujejo naslednje funkcije: • ocena lege; • usmerjanje lege; • obvladovanje lege; • obvladovanje orbite; • ocena orbite, v tem dokumentu imenovana »krmiljenje«, je lahko del funkcije za misije, ki izrecno zahtevajo to funkcijo; • zasedanje in ohranjanje varne lege v nujnih primerih in vračanje v nazivno misijo po izvedbi ukaza. Ta standard ne obravnava misij, ki vključujejo naslednje funkcije: • usmerjanje in nadzor poti na krovu v realnem času; • ocena in nadzor relativnega položaja na krovu v realnem času. Primeri tovrstnih misij so točka srečanja, letenje v formaciji, nosilne rakete in interplanetarna vozila. Čeprav ta dokument ne obravnava zgoraj navedenih vrst misij, ga je mogoče uporabiti kot referenčni dokument zanje. Ta standard se lahko prilagodi posameznim lastnostim in omejitvam vesoljskega projekta v skladu s standardom ECSS-S-ST-00.
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Vesoljska tehnika - Zahteve za satelitski AOCS (sistem obvladovanja orbitalne lege /satelita/)Raumfahrttechnik - Anforderungen an Satelliten-AOCSIngénierie spatiale - Exigences pour le système de contrôle d'attitude et d'orbite d'un satelliteSpace engineering - Satellite AOCS requirements49.140Vesoljski sistemi in operacijeSpace systems and operations33.070.40SatelitSatelliteICS:Ta slovenski standard je istoveten z:EN 16603-60-30:2015SIST EN 16603-60-30:2015en,fr,de01-november-2015SIST EN 16603-60-30:2015SLOVENSKI
STANDARD
SIST EN 16603-60-30:2015
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16603-60-30
September 2015 ICS 49.140
English version
Space engineering - Satellite AOCS requirements
Ingénierie spatiale - Exigences pour le système de contrôle d'attitude et d'orbite d'un satellite
Raumfahrttechnik - Anforderungen an Satelliten-AOCS This European Standard was approved by CEN on 16 November 2014.
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 © 2015 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 16603-60-30:2015 E SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 2 Table of contents European foreword . 4 Introduction . 5 1 Scope . 6 2 Normative references . 7 3 Terms definitions and abbreviated terms . 8 3.1 Terms from other standards . 8 3.2 Terms specific to the present Standard . 8 3.3 Abbreviated terms. 11 3.4 Nomenclature . 12 4 Principles . 13 4.1 Purpose and applicability . 13 4.2 Tailoring . 13 4.3 Relation between AOCS level and higher level requirements . 14 5 Requirements . 15 5.1 Functional and FDIR requirements . 15 5.1.1 General functional requirements . 15 5.1.2 Fault management requirements . 20 5.1.3 Propulsion related functional requirements . 21 5.2 Operational requirements . 22 5.2.1 Requirements for ground telecommand . 22 5.2.2 Requirements for telemetry . 24 5.2.3 Requirements for autonomous operations . 25 5.2.4 Requirement for calibration operations . 25 5.2.5 Requirements related to the satellite database . 26 5.3 Performance requirements . 26 5.3.1 Flight domain . 26 5.3.2 Normal mode . 26 SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 3 5.3.3 Orbit knowledge and control . 29 5.3.4 Attitude agility . 31 5.3.5 Performances outages . 31 5.3.6 Acquisition and safe mode . 32 5.3.7 Performance budgets . 32 5.4 Verification requirements . 33 5.4.1 Scope. 33 5.4.2 Overview . 33 5.4.3 Verification facilities . 34 5.4.4 AOCS design and performance verification . 36 5.4.5 AOCS hardware/software verification . 37 5.4.6 Verification at satellite level . 37 5.4.7 AOCS-ground interface verification . 38 5.4.8 In-flight verification . 38 5.5 Documentation requirements . 39 5.5.1 Overview . 39 5.5.2 Required documentation . 39 Annex A (normative) Design Definition File (DDF) for AOCS - DRD . 40 Annex B (normative) Design Justification File (DJF) for AOCS-DRD . 42 Annex C (normative) AOCS Algorithms and Functional Description - DRD . 44 Annex D (normative) Verification Plan (VP) for AOCS - DRD . 46 Annex E (normative) User Manual (UM) for AOCS - DRD . 48 Annex F (informative) AOCS Documentation delivery by Phase . 50 Bibliography . 51
Tables Table F-1 : Typical AOCS documentation. 50
SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 4 European foreword This document (EN 16603-60-30:2015) has been prepared by Technical Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN. This standard (EN 16603-60-30:2015) originates from ECSS-E-ST-60-30C. 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 March 2016, and conflicting national standards shall be withdrawn at the latest by March 2016. 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 prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. 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. SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 5 Introduction The Attitude and Orbit Control System (AOCS) requirements for the development of space programmes are typically part of the Project Requirements Document. The level of completeness and the level of detail vary very much from project to project.
This Standard provides a baseline for the AOCS requirements which are used in the specification and the validation process. The Standard is intended to be used for each programme as an input for writing the Project Requirements Document. It includes all subjects related to AOCS: • Functional and FDIR requirements • Operational requirements • Performance requirements • Verification requirements • Documentation requirements SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 6 1 Scope This Standard specifies a baseline for the attitude and orbit control system requirements to be used in the Project Requirements Document for space applications.
Project requirements documents are included in business agreements, which are agreed between the parties and binding them, at any level of space programmes, as described in ECSS-S-ST-00.
This Standard deals with the attitude and orbit control systems developed as part of a satellite space project. The classical attitude and orbit control systems considered here include the following functions: • Attitude estimation • Attitude guidance • Attitude control • Orbit control • Orbit estimation, called Navigation in this document, can be part of the function for missions which explicitly require this function • Acquisition and maintenance of a safe attitude in emergency cases and return to nominal mission upon command The present Standard does not cover missions that include the following functions:
• Real-time on-board trajectory guidance and control • Real-time on-board relative position estimation and control Example of such missions are rendezvous, formation flying, launch vehicles and interplanetary vehicles. Although the present document does not cover the above mentioned types of mission, it can be used as a reference document for them. This standard may be tailored for the specific characteristic and constraints of a space project in conformance with ECSS-S-ST-00. SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 7 2 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 revision of, any of these publications do not apply. However, parties to agreements based on this ECSS Standard are encouraged to investigate the possibility of applying the more 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 16603-10 ECSS-E-ST-10 Space engineering - System engineering general requirements EN 16603-10-03 ECSS-E-ST-10-03 Space engineering - Testing EN 16603-60-10 ECSS-E-ST-60-10 Space engineering - Control performances EN 16603-70-11 ECSS-E-ST-70-11 Space engineering - Space segment operability
SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 8 3 Terms definitions and abbreviated terms 3.1 Terms from other standards For the purpose of this Standard, the terms and definitions from ECSS-ST-00-01, ECSS-E-ST-10 and ECSS-E-ST-60-10 apply.
In particular, the following terms are used in the present Standard, with the definition given in the ECSS-E-ST-60-10: • Absolute knowledge error (AKE) • Absolute performance error (APE) • Relative knowledge error (RKE) • Relative performance error (RPE) • Robustness 3.2 Terms specific to the present Standard The definitions given in this clause are specific to the present Standard and are applicable for the understanding of the requirements. Other names or definitions may be used however during the development of space programmes. 3.2.1 attitude and orbit control system (AOCS) functional chain of a satellite which encompasses attitude and orbit sensors, attitude estimation and guidance, attitude and orbit control algorithms, attitude and orbit control actuators NOTE 1 The AOCS can include an orbit estimation function usually called Navigation. NOTE 2 The AOCS can include additional items such as AOCS dedicated computer and AOCS application software, depending on satellite architecture.
SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 9 3.2.2 AOCS mode state of the AOCS for which a dedicated set of equipment and algorithms is used to fulfil operational objectives and requirements 3.2.3 AOCS functional simulator fully numerical simulator used to verify the AOCS design, algorithms, parameters and performances NOTE The AOCS functional simulator can be a collection of unitary numerical simulators, provided that a full coverage of the verification is ensured. 3.2.4 avionics test bench facility dedicated to the validation of the avionics and its constituents NOTE 1 The avionics content and definition can vary from one programme to another. It includes as a minimum the platform on-board computer and platform software, the Data Handling functions, the AOCS sensors and actuators. NOTE 2 This facility includes numerical models and/or real hardware representative of flight units. The avionics test bench is used to validate the AOCS behaviour in real-time conditions, including hardware-software interfaces. 3.2.5 AOCS end-to-end tests tests defined to validate complete AOCS loops on the satellite, including all the real components such as hardware, software and wiring NOTE End-to-end tests can be performed in open loop or closed loop. 3.2.6 flight dynamics (FD) functionalities performed on ground in support of on-board AOCS/GNC NOTE Examples include orbit manoeuvres computation, guidance, AOCS/GNC TC generation and ephemerides. 3.2.7 guidance navigation and control functions (GNC) functions in charge of targeted orbit and attitude computation, attitude and orbit determination, attitude and orbit control NOTE GNC versus AOCS: the term AOCS is commonly used when the orbit guidance is not performed on board, which is the case for standard LEO, MEO and GEO missions. GNC is commonly used for the on-board segment, when the satellite position is controlled in closed loop, for instance in case of rendezvous SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 10 and formation flying. The GNC term can be also used for the whole function, distributed between on-board and ground systems. 3.2.8 sensitivity analysis identification of the parameters which impact the AOCS performance, and assessment of their individual contribution to this performance NOTE 1 Only the dominating contributors are of interest. These contributors can include: • Noise, bias and misalignment, for the AOCS sensors and actuators • Satellite mass properties • Satellite configuration variation, e.g. solar array position, sensors and actuators configuration • Measurements outages
• Environmental conditions • External and internal disturbances NOTE 2 The AOCS performance can be for instance:
• Pointing accuracy • Duration of a manoeuvre • Fuel consumption NOTE 3 The objective is to have an order of magnitude of the contribution, and this can be achieved by analysis, simulation or test. 3.2.9 worst case analysis deterministic analysis to identify a set of parameters, disturbances and initial conditions, which, when combined at some given values within their nominal operational range, define a worst case situation or scenario for the evaluation of AOCS performances NOTE 1 The parameter variations and disturbances are as defined for the sensitivity analysis, and their selection can rely on a sensitivity analysis. NOTE 2 The initial conditions can be for instance: • Angular rates • Initial angular momentum • Sun, Earth or planetary positions • Orbit parameters NOTE 3 The worst case scenarios depend on the considered AOCS performance. 3.2.10 tranquilization phase phase following an attitude manoeuvre, or possibly an orbit correction manoeuvre, during which the full attitude performance is not yet achieved
SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 11 3.3 Abbreviated terms The following abbreviated terms are defined and used within this document: Abbreviation Meaning AOCS attitude and orbit control system AKE absolute knowledge error APE absolute performance error ATB avionics test bench CDR critical design review CoM centre of mass DDF design definition file DJF design justification file DRD document requirements definition ECEF Earth centred Earth frame EM engineering model FDIR failure detection, isolation and recovery FD flight dynamics FM flight model FMECA failure mode, effects and criticality analysis
GEO geostationary orbit GNC guidance navigation and control GNSS global navigation satellite system H/W
hardware I/F interface ICD interface control document LEO low Earth orbit LEOP launch and early orbit phase MCI mass, CoM and inertia MEO medium Earth orbit MRD mission requirements document P/L
payload PDR preliminary design review PRD project requirements document QR qualification review RKE relative knowledge error RPE relative performance error S/C
spacecraft SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 12 Abbreviation Meaning S/W
software SRD system requirements document
SSUM space segment user manual TBD to be defined TBS to be specified TC telecommand TM telemetry UM user manual VCD verification control document VP verification plan 3.4 Nomenclature The following nomenclature applies throughout this document: a. The word “shall” is used in this Standard to express requirements. All the requirements are expressed with the word “shall”. b. The word “should” is used in this Standard to express recommendations. All the recommendations are expressed with the word “should”. NOTE It is expected that, during tailoring, all the recommendations in this document are either converted into requirements or tailored out. c. The words “may” and “need not” are used in this Standard to express positive and negative permissions, respectively. All the positive permissions are expressed with the word “may”. All the negative permissions are expressed with the words “need not”. d. The word “can” is used in this Standard to express capabilities or possibilities, and therefore, if not accompanied by one of the previous words, it implies descriptive text. NOTE In ECSS “may” and “can” have completely different meanings: “may” is normative (permission), and “can” is descriptive. e. The present and past tenses are used in this Standard to express statements of fact, and therefore they imply descriptive text. SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 13 4 Principles 4.1 Purpose and applicability The purpose of this Standard is to provide a baseline for the attitude and orbit control system requirements to be used in the Project Requirements Document for space programmes at all levels of the customer-supplier chain above AOCS. It is intended to be applied by the highest level customer to the prime contractor, for instance through the MRD or SRD. This Standard is not directly applicable to the AOCS contractor, whose contractual specification document is a PRD derived from this Standard. Considering the large variety of space missions, the large variety of AOCS functions and AOCS performances, and the variety of industrial organizations, it is not possible to propose AOCS requirements directly adapted to each situation. Therefore this document specifies a requirement on each subject, to be tailored, as explained in clause 4.2. This Standard contains a number of "TBS" requirements, especially in clause 5.3, because these requirements cannot be generically defined. Numerical values and the performance statistical interpretation depend on each specific project. 4.2 Tailoring For each mission, it is necessary to adapt the specified requirements through a complete tailoring process, that is • to decide if a requirement is necessary, taking into account the specific functionalities required for the mission. For instance, if a mission requires an on-board navigation function, then requirements dedicated to this function or to an on-board GNSS receiver are applicable. As another example, clause 5.3 contains a list of typical performance requirements, which can be useful for some missions but unnecessary for others. • to decide whether the requirement might be better placed in a statement of work rather than in a specification. • to adapt the numerical values of a requirement, considering the exact performances required for the mission. SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 14 • to quantify the new hardware and software development necessary for the programme, which is a key factor in adapting the verification requirements of clause 5.4. Tailoring can also be made necessary by the industrial organization, for instance: • the prime is responsible (or not) for AOCS, • the AOCS contractor is also responsible for other functions such as propulsion and software, • the AOCS contractor is responsible (or not) for the procurement of AOCS units and computer, • the AOCS contractor is involved (or not) in the satellite operations and flight dynamics. The notes provided with the requirements help to decide if the requirement is applicable, or to decide how to adapt it for a dedicated mission. The formulation “depending on the mission” is also used sometimes in the requirements, with some indications on this dependency, when it is clear that it has to be considered as applicable for some missions, and not applicable for others. 4.3 Relation between AOCS level and higher level requirements The requirements listed in this document are expressed at AOCS level. The pointing performance requirements originate from mission requirements, expressed in various ways directly linked to the final objective of the mission. The engineering work necessary to translate the original mission requirements into AOCS level requirements, or to make an apportionment between several contributors, is not addressed in this document. Moreover, in some cases it can be preferable to keep the performance requirements expressed at mission level and not at AOCS level, in order to allow the best optimization of the system. In such cases, the AOCS pointing performance requirements can be omitted.
The Failure Detection, Isolation and Recovery (FDIR) is usually defined and specified at satellite level. The FDIR requirements included in this document relate to the contribution from AOCS. But this Standard does not specify the FDIR implementation architecture. It is compatible with architectures, where a part of the FDIR is implemented locally at AOCS level. The required AOCS documentation is defined in clause 5.5.2a, with the key documents being specified in the DRD annexes. A major part of this documentation can be part of the satellite level or avionics level documentation. SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 15 5 Requirements 5.1 Functional and FDIR requirements 5.1.1 General functional requirements 5.1.1.1 High level functions a. The AOCS shall provide the hardware and software capabilities and performances: 1. to perform the attitude measurement, estimation, guidance and control needed for the mission; 2. to perform the orbit control manoeuvres, as specified by the mission requirements; 3. to ensure a safe state of the spacecraft at any time, including emergency and anomaly situations, according to failure management requirements; 4. to ensure the mission availability, as specified at satellite level. NOTE For points 3 and 4, AOCS only contributes to these higher level functions. 5.1.1.2 Attitude acquisition and keeping a. The AOCS shall provide during all phases of the mission the capability to acquire and keep all attitudes necessary to perform the mission. NOTE 1 The concerned attitude can cover the LEOP phase, the attitude on-station in nominal and degraded situations, the cases of emergency or the orbit correction manoeuvre attitude. NOTE 2 The attitude can be defined explicitly or through constraints. NOTE 3 Attitude keeping can be suspended for periods of limited duration to allow for appendage deployment (typically solar array or high-gain antenna) or for module separation in multi-module spacecraft. SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 16 b. The AOCS modes used for initial acquisition shall provide the capability for transition, from the initial attitude and rate after launcher separation to the final mission pointing, in a safe and orderly sequence. NOTE Specific requirements can be placed on the acquisition modes regarding the capability during this phase to deploy various appendages, such as solar arrays and antennas (partial or full deployment). 5.1.1.3 Attitude determination a. The AOCS shall provide, as specified by the mission requirements, the hardware and software means for autonomous on-board attitude determination. NOTE For some missions, payload measurement data can be used directly in the satellite control loop. This “payload in the loop” design can be justified to meet high accuracy requirements. 5.1.1.4 Orbit determination a. If a navigation function is necessary for the mission, the AOCS shall provide the hardware and software means for autonomous on-board determination of the spacecraft orbital state which includes position, velocity and time. NOTE Orbit determination can be needed on board and/or on ground. 5.1.1.5 Reference frames a. The AOCS shall identify and define unambiguously reference frames needed for: 1. attitude measurement, 2. attitude control, 3. attitude guidance, 4. orbit navigation. NOTE 1 A possible selection and implementation of the reference frames can be respectively associated to: • the main AOCS attitude sensor for the attitude measurement and control, • the guidance target for the attitude guidance. NOTE 2 ECSS-E-ST-10-09 provides more information on unambiguous definitions of reference frames.
SIST EN 16603-60-30:2015
EN 16603-60-30:2015 (E) 17 5.1.1.6 Mission pointing a. The AOCS shall ensure that the attitude guidance and pointing specified by the mission requirements, during the mission operational phase are met.
NOTE 1 The possible pointing includes Earth pointing, nadir pointing and tracking of a fixed point on ground, inertial pointing, Sun pointing or pointing to scientific targets. NOTE 2 Attitudes can be constrained by payload and platform requirements related for example to illumination or platform thermal constraints. NOTE 3 Intermediate attitudes can be needed between mission operational sequences, or for the acquisition of new targets. NOTE 4 Specific attitudes can be needed for system purposes, like communications for instance. 5.1.1.7 Orbit acquisition and maintenance a. The AOCS shall provide the capability for achieving orbit control manoeuvres specified by mission analysis. NOTE Orbit control manoeuvres include the following cases:
• initial orbit acquisition or transfer phase so as to reach the operational orbit, • orbit correction manoeuvres on-station for orbit maintenance,
• orbit change on station for repositioning, • end-of-life orbit change for de-orbiting, transfer towards graveyard orbit or parking orbit. 5.1.1.8 Safe mode a. In case of major anomaly, the AOCS shall provide the autonomous capability to reach and control safe pointing attitude and angular rates to ensure the integrity of the spacecraft vital functions, including power, thermal and communications. NOTE 1 Depending on satellite design and operational sequences, the safe pointing attitude can be required to be compatible with several satellite mechanical configurations corresponding to solar arrays and appendages in stowed, partially deployed or fully deployed configurations. NOTE 2 Major anomalies are defined programme by programme. b. The entry into safe mode shall be commandable by ground TC. c. The ret
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Vesoljska tehnika - Zahteve za satelitski AOCS (sistem obvladovanja orbitalne lege /satelita/)Raumfahrttechnik - Anforderungen an Satelliten-AOCSIngénierie spatiale - Exigences pour le système de contrôle d'attitude et d'orbite d'un satelliteSpace engineering - Satellite AOCS requirements49.140Vesoljski sistemi in operacijeSpace systems and operations33.070.40SatelitSatelliteICS:Ta slovenski standard je istoveten z:FprEN 16603-60-30kSIST FprEN 16603-60-30:2014en,fr,de01-julij-2014kSIST FprEN 16603-60-30:2014SLOVENSKI
STANDARD
kSIST FprEN 16603-60-30:2014
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
FINAL DRAFT
FprEN 16603-60-30
May 2014 ICS 49.140
English version
Space engineering - Satellite AOCS requirements
Ingénierie spatiale - Exigences pour le système de contrôle d'attitude et d'orbite d'un satellite
Raumfahrttechnik - Anforderungen an Satelliten-AOCS This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee CEN/CLC/TC 5.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN and CENELEC 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.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard. 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. FprEN 16603-60-30:2014 E kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 2 Table of contents Foreword . 4 Introduction . 5 1 Scope . 6 2 Normative references . 7 3 Terms definitions and abbreviated terms . 8 3.1 Terms from other standards . 8 3.2 Terms specific to the present Standard . 8 3.3 Abbreviated terms. 11 3.4 Nomenclature . 12 4 Principles . 13 4.1 Purpose and applicability . 13 4.2 Tailoring . 13 4.3 Relation between AOCS level and higher level requirements . 14 5 Requirements . 15 5.1 Functional and FDIR requirements . 15 5.1.1 General functional requirements . 15 5.1.2 Fault management requirements . 20 5.1.3 Propulsion related functional requirements . 21 5.2 Operational requirements . 22 5.2.1 Requirements for ground telecommand . 22 5.2.2 Requirements for telemetry . 24 5.2.3 Requirements for autonomous operations . 25 5.2.4 Requirement for calibration operations . 25 5.2.5 Requirements related to the satellite database . 26 5.3 Performance requirements . 26 5.3.1 Flight domain . 26 5.3.2 Normal mode . 26 kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 3 5.3.3 Orbit knowledge and control . 29 5.3.4 Attitude agility . 31 5.3.5 Performances outages . 31 5.3.6 Acquisition and safe mode . 32 5.3.7 Performance budgets . 32 5.4 Verification requirements . 33 5.4.1 Scope. 33 5.4.2 Overview . 33 5.4.3 Verification facilities . 34 5.4.4 AOCS design and performance verification . 36 5.4.5 AOCS hardware/software verification . 37 5.4.6 Verification at satellite level . 37 5.4.7 AOCS-ground interface verification . 38 5.4.8 In-flight verification . 38 5.5 Documentation requirements . 39 5.5.1 Overview . 39 5.5.2 Required documentation . 39 Annex A (normative) Design Definition File (DDF) for AOCS - DRD . 40 Annex B (normative) Design Justification File (DJF) for AOCS-DRD . 42 Annex C (normative) AOCS Algorithms and Functional Description - DRD . 44 Annex D (normative) Verification Plan (VP) for AOCS - DRD . 46 Annex E (normative) User Manual (UM) for AOCS - DRD . 48 Annex F (informative) AOCS Documentation delivery by Phase . 50 Bibliography . 51
Tables Table F-1 : Typical AOCS documentation. 50
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FprEN 16603-60-30:2014 (E) 4 Foreword This document (FprEN 16603-60-30:2014) has been prepared by Technical Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN (Germany). This document (FprEN 16603-60-30:2014) originates from Error! Unknown document property name. This document is currently submitted to the Unique Acceptance Procedure. This document has been developed to cover specifically space systems and will the-refore have precedence over any EN covering the same scope but with a wider do-main of applicability (e.g. : aerospace). kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 5 Introduction The Attitude and Orbit Control System (AOCS) requirements for the development of space programmes are typically part of the Project Requirements Document. The level of completeness and the level of detail vary very much from project to project.
This Standard provides a baseline for the AOCS requirements which are used in the specification and the validation process. The Standard is intended to be used for each programme as an input for writing the Project Requirements Document. It includes all subjects related to AOCS: • Functional and FDIR requirements • Operational requirements • Performance requirements • Verification requirements • Documentation requirements kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 6 1 Scope This Standard specifies a baseline for the attitude and orbit control system requirements to be used in the Project Requirements Document for space applications.
Project requirements documents are included in business agreements, which are agreed between the parties and binding them, at any level of space programmes, as described in ECSS-S-ST-00.
This Standard deals with the attitude and orbit control systems developed as part of a satellite space project. The classical attitude and orbit control systems considered here include the following functions: • Attitude estimation • Attitude guidance • Attitude control • Orbit control • Orbit estimation, called Navigation in this document, can be part of the function for missions which explicitly require this function • Acquisition and maintenance of a safe attitude in emergency cases and return to nominal mission upon command The present Standard does not cover missions that include the following functions:
• Real-time on-board trajectory guidance and control • Real-time on-board relative position estimation and control Example of such missions are rendezvous, formation flying, launch vehicles and interplanetary vehicles. Although the present document does not cover the above mentioned types of mission, it can be used as a reference document for them. This standard may be tailored for the specific characteristic and constraints of a space project in conformance with ECSS-S-ST-00. kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 7 2 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 revision of, any of these publications do not apply. However, parties to agreements based on this ECSS Standard are encouraged to investigate the possibility of applying the more 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 16603-10 ECSS-E-ST-10 Space engineering - System engineering general requirements EN 16603-10-03 ECSS-E-ST-10-03 Space engineering - Testing EN 16603-60-10 ECSS-E-ST-60-10 Space engineering - Control performances EN 16603-70-11 ECSS-E-ST-70-11 Space engineering - Space segment operability
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FprEN 16603-60-30:2014 (E) 8 3 Terms definitions and abbreviated terms 3.1 Terms from other standards For the purpose of this Standard, the terms and definitions from ECSS-ST-00-01, ECSS-E-ST-10 and ECSS-E-ST-60-10 apply.
In particular, the following terms are used in the present Standard, with the definition given in the ECSS-E-ST-60-10: • Absolute knowledge error (AKE) • Absolute performance error (APE) • Relative knowledge error (RKE) • Relative performance error (RPE) • Robustness 3.2 Terms specific to the present Standard The definitions given in this clause are specific to the present Standard and are applicable for the understanding of the requirements. Other names or definitions may be used however during the development of space programmes. 3.2.1 attitude and orbit control system (AOCS) functional chain of a satellite which encompasses attitude and orbit sensors, attitude estimation and guidance, attitude and orbit control algorithms, attitude and orbit control actuators NOTE 1 The AOCS can include an orbit estimation function usually called Navigation. NOTE 2 The AOCS can include additional items such as AOCS dedicated computer and AOCS application software, depending on satellite architecture.
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FprEN 16603-60-30:2014 (E) 9 3.2.2 AOCS mode state of the AOCS for which a dedicated set of equipment and algorithms is used to fulfil operational objectives and requirements 3.2.3 AOCS functional simulator fully numerical simulator used to verify the AOCS design, algorithms, parameters and performances NOTE The AOCS functional simulator can be a collection of unitary numerical simulators, provided that a full coverage of the verification is ensured. 3.2.4 avionics test bench facility dedicated to the validation of the avionics and its constituents NOTE 1 The avionics content and definition can vary from one programme to another. It includes as a minimum the platform on-board computer and platform software, the Data Handling functions, the AOCS sensors and actuators. NOTE 2 This facility includes numerical models and/or real hardware representative of flight units. The avionics test bench is used to validate the AOCS behaviour in real-time conditions, including hardware-software interfaces. 3.2.5 AOCS end-to-end tests tests defined to validate complete AOCS loops on the satellite, including all the real components such as hardware, software and wiring NOTE End-to-end tests can be performed in open loop or closed loop. 3.2.6 flight dynamics (FD) functionalities performed on ground in support of on-board AOCS/GNC NOTE Examples include orbit manoeuvres computation, guidance, AOCS/GNC TC generation and ephemerides. 3.2.7 guidance navigation and control functions (GNC) functions in charge of targeted orbit and attitude computation, attitude and orbit determination, attitude and orbit control NOTE GNC versus AOCS: the term AOCS is commonly used when the orbit guidance is not performed on board, which is the case for standard LEO, MEO and GEO missions. GNC is commonly used for the on-board segment, when the satellite position is controlled in closed loop, for instance in case of rendezvous kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 10 and formation flying. The GNC term can be also used for the whole function, distributed between on-board and ground systems. 3.2.8 sensitivity analysis identification of the parameters which impact the AOCS performance, and assessment of their individual contribution to this performance NOTE 1 Only the dominating contributors are of interest. These contributors can include: • Noise, bias and misalignment, for the AOCS sensors and actuators • Satellite mass properties • Satellite configuration variation, e.g. solar array position, sensors and actuators configuration • Measurements outages
• Environmental conditions • External and internal disturbances NOTE 2 The AOCS performance can be for instance:
• Pointing accuracy • Duration of a manoeuvre • Fuel consumption NOTE 3 The objective is to have an order of magnitude of the contribution, and this can be achieved by analysis, simulation or test. 3.2.9 worst case analysis deterministic analysis to identify a set of parameters, disturbances and initial conditions, which, when combined at some given values within their nominal operational range, define a worst case situation or scenario for the evaluation of AOCS performances NOTE 1 The parameter variations and disturbances are as defined for the sensitivity analysis, and their selection can rely on a sensitivity analysis. NOTE 2 The initial conditions can be for instance: • Angular rates • Initial angular momentum • Sun, Earth or planetary positions • Orbit parameters NOTE 3 The worst case scenarios depend on the considered AOCS performance. 3.2.10 tranquilization phase phase following an attitude manoeuvre, or possibly an orbit correction manoeuvre, during which the full attitude performance is not yet achieved
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FprEN 16603-60-30:2014 (E) 11 3.3 Abbreviated terms The following abbreviated terms are defined and used within this document: Abbreviation Meaning AOCS attitude and orbit control system AKE absolute knowledge error APE absolute performance error ATB avionics test bench CDR critical design review CoM centre of mass DDF design definition file DJF design justification file DRD document requirements definition ECEF Earth centred Earth frame EM engineering model FDIR failure detection, isolation and recovery FD flight dynamics FM flight model FMECA failure mode, effects and criticality analysis
GEO geostationary orbit GNC guidance navigation and control GNSS global navigation satellite system H/W
hardware I/F interface ICD interface control document LEO low Earth orbit LEOP launch and early orbit phase MCI mass, CoM and inertia MEO medium Earth orbit MRD mission requirements document P/L
payload PDR preliminary design review PRD project requirements document QR qualification review RKE relative knowledge error RPE relative performance error S/C
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FprEN 16603-60-30:2014 (E) 12 Abbreviation Meaning S/W
software SRD system requirements document
SSUM space segment user manual TBD to be defined TBS to be specified TC telecommand TM telemetry UM user manual VCD verification control document VP verification plan 3.4 Nomenclature The following nomenclature applies throughout this document: a. The word “shall” is used in this Standard to express requirements. All the requirements are expressed with the word “shall”. b. The word “should” is used in this Standard to express recommendations. All the recommendations are expressed with the word “should”. NOTE It is expected that, during tailoring, all the recommendations in this document are either converted into requirements or tailored out. c. The words “may” and “need not” are used in this Standard to express positive and negative permissions, respectively. All the positive permissions are expressed with the word “may”. All the negative permissions are expressed with the words “need not”. d. The word “can” is used in this Standard to express capabilities or possibilities, and therefore, if not accompanied by one of the previous words, it implies descriptive text. NOTE In ECSS “may” and “can” have completely different meanings: “may” is normative (permission), and “can” is descriptive. e. The present and past tenses are used in this Standard to express statements of fact, and therefore they imply descriptive text. kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 13 4 Principles 4.1 Purpose and applicability The purpose of this Standard is to provide a baseline for the attitude and orbit control system requirements to be used in the Project Requirements Document for space programmes at all levels of the customer-supplier chain above AOCS. It is intended to be applied by the highest level customer to the prime contractor, for instance through the MRD or SRD. This Standard is not directly applicable to the AOCS contractor, whose contractual specification document is a PRD derived from this Standard. Considering the large variety of space missions, the large variety of AOCS functions and AOCS performances, and the variety of industrial organizations, it is not possible to propose AOCS requirements directly adapted to each situation. Therefore this document specifies a requirement on each subject, to be tailored, as explained in clause 4.2. This Standard contains a number of "TBS" requirements, especially in clause 5.3, because these requirements cannot be generically defined. Numerical values and the performance statistical interpretation depend on each specific project. 4.2 Tailoring For each mission, it is necessary to adapt the specified requirements through a complete tailoring process, that is • to decide if a requirement is necessary, taking into account the specific functionalities required for the mission. For instance, if a mission requires an on-board navigation function, then requirements dedicated to this function or to an on-board GNSS receiver are applicable. As another example, clause 5.3 contains a list of typical performance requirements, which can be useful for some missions but unnecessary for others. • to decide whether the requirement might be better placed in a statement of work rather than in a specification. • to adapt the numerical values of a requirement, considering the exact performances required for the mission. kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 14 • to quantify the new hardware and software development necessary for the programme, which is a key factor in adapting the verification requirements of clause 5.4. Tailoring can also be made necessary by the industrial organization, for instance: • the prime is responsible (or not) for AOCS, • the AOCS contractor is also responsible for other functions such as propulsion and software, • the AOCS contractor is responsible (or not) for the procurement of AOCS units and computer, • the AOCS contractor is involved (or not) in the satellite operations and flight dynamics. The notes provided with the requirements help to decide if the requirement is applicable, or to decide how to adapt it for a dedicated mission. The formulation “depending on the mission” is also used sometimes in the requirements, with some indications on this dependency, when it is clear that it has to be considered as applicable for some missions, and not applicable for others. 4.3 Relation between AOCS level and higher level requirements The requirements listed in this document are expressed at AOCS level. The pointing performance requirements originate from mission requirements, expressed in various ways directly linked to the final objective of the mission. The engineering work necessary to translate the original mission requirements into AOCS level requirements, or to make an apportionment between several contributors, is not addressed in this document. Moreover, in some cases it can be preferable to keep the performance requirements expressed at mission level and not at AOCS level, in order to allow the best optimization of the system. In such cases, the AOCS pointing performance requirements can be omitted.
The Failure Detection, Isolation and Recovery (FDIR) is usually defined and specified at satellite level. The FDIR requirements included in this document relate to the contribution from AOCS. But this Standard does not specify the FDIR implementation architecture. It is compatible with architectures, where a part of the FDIR is implemented locally at AOCS level. The required AOCS documentation is defined in clause 5.5.2a, with the key documents being specified in the DRD annexes. A major part of this documentation can be part of the satellite level or avionics level documentation. kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 15 5 Requirements 5.1 Functional and FDIR requirements 5.1.1 General functional requirements 5.1.1.1 High level functions a. The AOCS shall provide the hardware and software capabilities and performances: 1. to perform the attitude measurement, estimation, guidance and control needed for the mission; 2. to perform the orbit control manoeuvres, as specified by the mission requirements; 3. to ensure a safe state of the spacecraft at any time, including emergency and anomaly situations, according to failure management requirements; 4. to ensure the mission availability, as specified at satellite level. NOTE For points 3 and 4, AOCS only contributes to these higher level functions. 5.1.1.2 Attitude acquisition and keeping a. The AOCS shall provide during all phases of the mission the capability to acquire and keep all attitudes necessary to perform the mission. NOTE 1 The concerned attitude can cover the LEOP phase, the attitude on-station in nominal and degraded situations, the cases of emergency or the orbit correction manoeuvre attitude. NOTE 2 The attitude can be defined explicitly or through constraints. NOTE 3 Attitude keeping can be suspended for periods of limited duration to allow for appendage deployment (typically solar array or high-gain antenna) or for module separation in multi-module spacecraft. kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 16 b. The AOCS modes used for initial acquisition shall provide the capability for transition, from the initial attitude and rate after launcher separation to the final mission pointing, in a safe and orderly sequence. NOTE Specific requirements can be placed on the acquisition modes regarding the capability during this phase to deploy various appendages, such as solar arrays and antennas (partial or full deployment). 5.1.1.3 Attitude determination a. The AOCS shall provide, as specified by the mission requirements, the hardware and software means for autonomous on-board attitude determination. NOTE For some missions, payload measurement data can be used directly in the satellite control loop. This “payload in the loop” design can be justified to meet high accuracy requirements. 5.1.1.4 Orbit determination a. If a navigation function is necessary for the mission, the AOCS shall provide the hardware and software means for autonomous on-board determination of the spacecraft orbital state which includes position, velocity and time. NOTE Orbit determination can be needed on board and/or on ground. 5.1.1.5 Reference frames a. The AOCS shall identify and define unambiguously reference frames needed for: 1. attitude measurement, 2. attitude control, 3. attitude guidance, 4. orbit navigation. NOTE 1 A possible selection and implementation of the reference frames can be respectively associated to: • the main AOCS attitude sensor for the attitude measurement and control, • the guidance target for the attitude guidance. NOTE 2 ECSS-E-ST-10-09 provides more information on unambiguous definitions of reference frames.
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FprEN 16603-60-30:2014 (E) 17 5.1.1.6 Mission pointing a. The AOCS shall ensure that the attitude guidance and pointing specified by the mission requirements, during the mission operational phase are met.
NOTE 1 The possible pointing includes Earth pointing, nadir pointing and tracking of a fixed point on ground, inertial pointing, Sun pointing or pointing to scientific targets. NOTE 2 Attitudes can be constrained by payload and platform requirements related for example to illumination or platform thermal constraints. NOTE 3 Intermediate attitudes can be needed between mission operational sequences, or for the acquisition of new targets. NOTE 4 Specific attitudes can be needed for system purposes, like communications for instance. 5.1.1.7 Orbit acquisition and maintenance a. The AOCS shall provide the capability for achieving orbit control manoeuvres specified by mission analysis. NOTE Orbit control manoeuvres include the following cases:
• initial orbit acquisition or transfer phase so as to reach the operational orbit, • orbit correction manoeuvres on-station for orbit maintenance,
• orbit change on station for repositioning, • end-of-life orbit change for de-orbiting, transfer towards graveyard orbit or parking orbit. 5.1.1.8 Safe mode a. In case of major anomaly, the AOCS shall provide the autonomous capability to reach and control safe pointing attitude and angular rates to ensure the integrity of the spacecraft vital functions, including power, thermal and communications. NOTE 1 Depending on satellite design and operational sequences, the safe pointing attitude can be required to be compatible with several satellite mechanical configurations corresponding to solar arrays and appendages in stowed, partially deployed or fully deployed configurations. NOTE 2 Major anomalies are defined programme by programme. b. The entry into safe mode shall be commandable by ground TC. c. The return from safe mode shall be commandable by ground TC kSIST FprEN 16603-60-30:2014
FprEN 16603-60-30:2014 (E) 18 5.1.1.9 AOCS mode transitions a. The AOCS shall define a strategy for the implementation of the mode transitions and describe how this strategy is applied for each AOCS mode transition, including the following items: 1. transition conditions and the check performed by the on-board software, 2. actions on software and hardware performed autonomously on board, 3. actions to be performed on ground.
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