SIST EN 16603-60-21:2018

SLOVENSKI STANDARD
SIST EN 16603-60-21:2018
01-november-2018
9HVROMVNDWHKQLND7HUPLQRORJLMDQDSRGURþMXåLURVNRSRYLQWHKQLþQDVSHFLILNDFLMD
Space engineering - Gyros terminology and performance specification
Raumfahrttechnik - Kreiselinstrumente - Terminologie und Leistungsspezifikation
Ingénierie spatiale - Spécification des performances et terminologie des gyros
Ta slovenski standard je istoveten z: EN 16603-60-21:2018
ICS:
01.040.49 Letalska in vesoljska tehnika Aircraft and space vehicle
(Slovarji) engineering (Vocabularies)
49.140 Vesoljski sistemi in operacije Space systems and
operations
SIST EN 16603-60-21:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 16603-60-21:2018


EUROPEAN STANDARD
EN 16603-60-21

NORME EUROPÉENNE

EUROPÄISCHE NORM
September 2018
ICS 01.040.49; 49.090; 49.140

English version

Space engineering - Gyros terminology and performance
specification
Ingénierie spatiale - Spécification des performances et Raumfahrttechnik - Kreiselinstrumente - Terminologie
terminologie des gyros und Leistungsspezifikation
This European Standard was approved by CEN on 11 July 2018.

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,
Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.






















CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2018 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. EN 16603-60-21:2018 E
reserved worldwide for CEN national Members and for
CENELEC Members.

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Table of contents
European Foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 9
3.1 Terms from other standards . 9
3.2 Terms specific to the present standard . 9
3.3 Abbreviated terms. 15
4 Functional requirements . 16
4.1 Overview . 16
4.2 Operating modes . 16
4.2.1 Operating modes Functional requirements . 16
4.2.2 Operating modes Verification requirement . 17
4.3 Start-up . 17
4.3.1 Start-up Functional requirements . 17
4.3.2 Start-up Verification requirements . 17
4.4 Warm-up . 18
4.4.1 Warm-up Functional requirements . 18
4.4.2 Warm-up Verification requirements . 18
4.5 Time and frequency, datation and synchronisation . 18
4.5.1 Time and frequency Functional requirements . 18
4.5.2 Time and frequency Verification requirements . 19
4.6 Alignment and scale factor . 19
4.6.1 Alignment and scale factor Functional requirements . 19
4.6.2 Alignment and scale factor Verification requirements . 20
4.7 Commandability and observability . 20
4.7.1 Commandability and observability Functional requirements . 20
4.7.2 Commandability and observability Verification requirements . 20
4.8 Failure diagnosis . 20
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4.8.1 Failure diagnosis Functional requirements . 20
4.8.2 Failure diagnosis Verification requirements . 21
4.9 Measurement mode . 21
4.9.1 Measurement mode Functional requirements . 21
4.9.2 Measurement mode Verification requirements . 21
4.10 Auxiliary modes . 21
4.10.1 Auxiliary modes Functional requirements . 21
4.10.2 Auxiliary modes Verification requirements . 22
4.11 Anti-aliasing filter . 22
4.11.1 Anti-aliasing Functional requirements. 22
4.11.2 Anti-aliasing Verification requirements . 22
4.12 Stimulation . 22
4.12.1 Stimulation Functional requirements . 22
4.12.2 Stimulation Verification requirement . 22
4.13 Lifetime and duty cycle . 23
4.13.1 Lifetime and duty cycle Functional requirements . 23
4.13.2 Lifetime and duty cycle Verification requirement . 23
5 Performance requirements . 24
5.1 Use of the statistical ensemble . 24
5.1.1 Overview . 24
5.1.2 Provisions . 24
5.2 Performance Verification requirements . 25
5.3 General Performance requirements . 25
5.4 General performance metrics . 26
5.4.1 Overview and definition . 26
5.4.2 Bias . 27
5.4.3 Noise. 32
5.4.4 Scale factor error . 35
5.4.5 Misalignment . 38
5.4.6 Measurement datation and latency . 41
5.4.7 Start-up performances . 42
5.4.8 Warm-up phase performances . 43
5.4.9 Measured output bandwidth . 43
5.4.10 Anti-aliasing filter . 43
5.4.11 Data quantization . 44
5.4.12 Failure detection efficiency . 44
5.4.13 Stimulation . 45
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5.5 Functional and performance mathematical model . 45
Annex A (normative) Functional and performance mathematical model
(FMM) description - DRD . 48
Annex B (informative) Example of data sheet . 50
Bibliography . 52

Figures
Figure 3-1: example alignment reference frame . 10
Figure 3-2: mechanical reference frame (MRF) . 14
Figure 4-1: Example of Start-up and Warm-up phases . 18
Figure 5-1: Examples of Bias evaluation from test or simulation data . 27
Figure 5-2: Switch-on bias repeatability computation . 31
Figure 5-3: Bias stability computation . 32
Figure 5-4: Monolateral PSD and Allan Variance. 34
Figure 5-5: Example of Functional Mathematical Model Architecture . 47

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European Foreword
This document (EN 16603-60-21:2018) has been prepared by Technical
Committee CEN-CENELEC/TC 5 “Space”, the secretariat of which is held by
DIN.
This standard (EN 16603-60-21:2018) originates from ECSS-E-ST-60-21C.
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
2019, and conflicting national standards shall be withdrawn at the latest by
March 2019.
Attention is drawn to the possibility that some of the elements of this document
may be the subject of patent rights. CEN shall not be held responsible for
identifying any or all such patent rights.
This document has been prepared under a standardization request 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, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
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Introduction
This Standard is intended to support the variety of space borne gyros either
available or under development, with the exception of the gyros used for the
launch vehicles.
This standard defines the terminology and specifications for the functions and
performance of gyros used on spacecraft. It focuses on the specific topics to be
found in the gyros procurement specification documents and is intended to be
used as a structured set of systematic provisions.
This standard is split in three main clauses:
• Terminology (clause 3)
• Functional requirements (clause 4)
• Performance requirements (clause 5)
NOTE This standard does not contain textbook material
on gyro technology. The readers and the users are
assumed to possess general knowledge of gyro
technology and its applications to space missions.
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1
Scope
This Standard specifies gyros functions and performances as part of a space
project. This Standard covers aspects of functional and performance
requirements, including nomenclature, definitions, functions and performance
metrics for the performance specification of spaceborne gyros.
The Standard focuses on functional and performance specifications with the
exclusion of mass and power, TM/TC interface and data structures.
When viewed from the perspective of a specific project context, the
requirements defined in this Standard can be tailored to match the genuine
requirements of a particular profile and circumstances of a project.
The requirements verification by test can be performed at qualification level
only or also at acceptance level. It is up to the Supplier, in agreement with the
customer, to define the relevant verification approach in the frame of a specific
procurement, in accordance with clause 5.2 of ECSS-E-ST-10-02.
The present standard does not cover gyro use for launch vehicles.
This standard can be tailored for the specific characteristics and constraints of a
space project in conformance with ECSS-S-ST-00.
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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

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3
Terms, definitions and abbreviated terms
3.1 Terms from other standards
a. For the purpose of this Standard, the terms and definitions from ECSS-S-
ST-00-01 apply, in particular the following terms:
1. acceptance
2. assembly
3. availability
4. configuration
5. failure
6. lifetime
7. performance
8. qualification
9. redundancy
3.2 Terms specific to the present standard
3.2.1 alignment reference frame (ARF)
frame that is fixed with respect to the gyro external optical cube where and
whose origin is defined unambiguously with reference to the gyro external
optical cube
NOTE 1 The X, Y and Z axes of the ARF are a right-handed
orthogonal set of axes which are defined
unambiguously with respect to the normal of the
faces of the external optical cube. Figure 3-1
schematically illustrates the definition of the ARF.
NOTE 2 If the optical cube’s faces are not perfectly
orthogonal, the X-axis can be defined as the
projection of the normal of the X-face in the plane
orthogonal to the Z-axis, and the Y-axis completes
the RHR.
NOTE 3 The ARF is the frame used to align the sensor
during integration.
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NOTE 4 This definition does not attempt to prescribe a
definition of the ARF, other than it is a frame fixed
relative to the physical geometry of the sensor
optical cube.
NOTE 5 This term is defined in the present standard with a
different meaning than in ECSS-E-ST-60-20. The
term with the meaning defined herein is applicable
only to the present standard.

Z
ARF
Y
ARF
X
ARF
Sensor
Optical
Cube

Figure 3-1: example alignment reference frame
3.2.2 angular increment
angular rotation between two user requests
3.2.3 angular random walk (ARW)
white noise on the gyro rate output, corresponding to a -1 slope on the Allan
variance plot to a -1/2 slope on the Allan variance standard deviation plot and
to a flat slope on the PSD plot
NOTE The plots are measured in log/log scale.
3.2.4 angular white noise (AWN).
white angle noise which corresponds to a -2 slope on the Allan variance plot, to
a -1 slope on the Allan variance standard deviation plot and to a +2 slope on the
PSD plot.
NOTE The plots are measured in log/log scale.
3.2.5 anti-aliasing filter
filter implemented in the gyro in order to avoid the aliasing of the high
frequency motion of the spacecraft input signal
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3.2.6 bias
gyro measurement errors that are non-stochastic and not input rate dependant,
computed as the average of the rate error value over a defined time period
NOTE This term is defined in the present standard with a
different meaning than in ECSS-E-ST-60-20. The
term with the meaning defined herein is applicable
only to the present standard.
3.2.7 bias instability
low frequency noise component corresponding to flat slope on the Allan
variance standard deviation plot and to a -1 slope on the PSD plot
NOTE The plots are measured in log/log scale.
3.2.8 calibration
set of activities based on a set of tests allowing to characterise the gyro non-
random performance and, when relevant, to define the compensation
parameters used to improve the performance
NOTE This term is defined in the present standard with a
different meaning than in ECSS-S-ST-00-01. The
term with the meaning defined herein is applicable
only to the present standard.
3.2.9 configuration status
telemetry word indicating the states of the gyro tuneable settings
NOTE The configuration status scope is typically defined
by the gyro supplier.
3.2.10 cumulated angular increments
summation of angular increments
NOTE cumulated increments data output do not
correspond to an angular rotation between two
requests but to a cumulated angular rotation. The
customer typically manages the overflow. The use
of cumulated angular increments is robust to
transient data transmission issue.
3.2.11 deadband
input rotation range inside which the gyro output variation is less than a
specified value of the movement applied variation
NOTE The specified valued is normally expressed as a
percentage of the movement applied variation.
3.2.12 frozen outputs
situation occurring when the gyro output is erroneously identical over several
measurement acquisitions despite variation of the input signal
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3.2.13 health status
telemetry word which contains the gyro internal monitoring survey results
NOTE The internal monitoring survey parameters are
defined by the gyro supplier.
3.2.14 input axis misalignment
angular error between the real sensing axis and the gyro reference sensing axis
3.2.15 multiple-axis configuration
gyro configuration with several sensing axes on the same mechanical structure
and oriented along different directions, physically defined w.r.t. the mechanical
reference frame (MRF) or the alignment reference frame (ARF)
3.2.16 noise
high frequency or short duration errors
NOTE 1 Noise measurements and noise model
characterization can be done at various
temperatures. However, during noise
measurement, gyro channel environmental
temperature is assumed identical within a
specified temperature range.
NOTE 2 This term is defined in the present standard with a
different meaning than in ECSS-E-ST-32-11. The
term with the meaning defined herein is applicable
only to the present standard.
3.2.17 quantisation error
noise due to the digital nature of the gyro output
NOTE This component of noise has the same asymptotic
behaviour than the AWN on Allan variance and
PSD plots.
3.2.18 repeatability
degree of closeness of test results taken during different periods of operations
NOTE 1 For instance before and after thermal cycles and
other environmental exposures, between
shutdowns and according to time between runs.
Unless otherwise specified, measurements are
carried-out in the same environmental conditions
(in particular, gyro channel environmental
temperature being assumed identical within a
specified temperature range).
NOTE 2 This term is defined in the present standard with a
different meaning than in ECSS-E-ST-35 and ECSS-
Q-ST-20. The term with the meaning defined
herein is applicable only to the present standard.
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3.2.19 rate random walk (RRW)
noise component which corresponds to a +1 slope on the Allan variance plot to
a +1/2 slope on the Allan variance standard deviation plot and to a -2 slope on
the PSD plot.
NOTE The plots are measured in log/log scale.
3.2.20 scale factor non linearity
deviation of the output from a reference scale factor, over a given dynamic
range
NOTE the scale factor non linearity can be determined,
for example, by a least square linear fit of the
input/output data
3.2.21 scale factor non linearity error
residual errors after compensation of the scale factor non linearity component
3.2.22 scale factor error
gyro measurement errors that are non-stochastic and dependant of the rate
applied on the input axis
3.2.23 sensitivity
variation induced by a given environmental change, all other environmental
conditions being assumed unchanged and gyro channel being in continuous
operation
NOTE An environmental change can be, for example, a
change in temperature.
3.2.24 single-axis configuration
gyro configuration with only one sensing axis
3.2.25 stability
variation over a defined time period during which the gyro channel is
continuously submitted to specific operating conditions
NOTE  Unless otherwise specified, measurements are
carried-out in the same environmental conditions
(in particular, gyro channel environmental
temperature being assumed identical within a
specified temperature range).
3.2.26 start-up phase
time interval between the switch-on of the gyro unit and the presence of a valid
output of the gyro that is fulfilling the pertaining performance requirements
NOTE See also Figure 4-1.
3.2.27 stimulation
function that allows to inject a simulated dynamic angular profile to the gyro
for ground test purposes
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3.2.28 validity flag
flag that indicates whether the gyro measurement output is valid for use
3.2.29 warm-up duration
time interval between the switch-on of the gyro unit and the time when the full
nominal performances are achieved
NOTE See also Figure 4-1.
3.2.30 mechanical reference frame (MRF)
frame where the origin is defined unambiguously with reference to the
mounting interface plane of the gyro
NOTE 1 For example the Z-axis of the MRF is defined to be
perpendicular to the mounting interface plane,
which is the recommended convention. The X and
Y axes of the MRF are defined to lie in the
mounting plane such as to form an orthogonal
right hand rule reference frame (RHR) with the
MRF Z-axis.
NOTE 2 Figure 3-2 schematically illustrates the definition
of the MRF.
NOTE 3 If the gyro consists of several units, each unit has
its own MRF.
NOTE 4 This term is defined in the present standard with a
different meaning than in ECSS-E-ST-60-20. The
term with the meaning defined herein is applicable
only to the present standard.

Z
MRF
Y
MRF
Mounting Interface
X
Spacecraft Body
MRF

Figure 3-2: mechanical reference frame (MRF)
3.2.31 sensing reference frame (SRF)
physical reference frame in which individual gyro axes outputs are provided
NOTE 1 in case of a single-axis configuration, the sensing
axis is the Z-axis of the SRF.
NOTE 2 The sensing axis alignment w.r.t. the reference
frame (either MRF or ARF) is defined either by the
unitary vector of the ZSRF expressed in the
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reference frame or by the transfer matrix between
the SRF and the reference frame.
NOTE 3 The sensing axis misalignments are the angular
projections of the true Z sensing axis on the X_SRF
and Y_SRF. Misalignment errors are expressed as
half-cone errors, i.e. root-sum square of both
projections.
3.3 Abbreviated terms
For the purpose of this Standard, the abbreviated terms from ECSS-S-ST-00-01
and the following apply:
Abbreviation Meaning
alignment reference frame
ARF
angular white noise
AWN
beginning-of-life
BOL
document requirements definition
DRD
electrical ground support equipment
EGSE
end-of-life
EOL
functional mathematical model
FMM
housekeeping
HK
mechanical reference frame
MRF
part per million
PPM
power spectral density
PSD
right hand rule
RHR
rate random walk
RRW
single event effect
SEE
sensing reference frame
SRF
telemetry
TM
with respect to
w.r.t.

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4
Functional requirements
4.1 Overview
The gyro functional requirements address the following features:
• Operating modes and transient behaviours
• Timing aspects
• Lifetime and duty cycle
• Alignment and scale factor
• Commandability and observability
• Anti-aliasing
• Stimulation
The list of unit functional requirements is not exhaustive and generic functional
requirements (such as redundancy and reliability) are also considered in the
frame of a gyro requirements specification.
NOTE The requirements listed in clause 4 can be
complemented, as needed, with requirements
found in ECSS-E-ST-10, ECSS-E-ST-10-03, ECSS-E-
ST-60-30 and ECSS-E-ST-70-11.
4.2 Operating modes
4.2.1 Operating modes Functional requirements
a. The Gyro shall provide a Measurement Mode.
b. The TM data provided by the unit shall unambiguously report when the
Gyro has switched from Start-Up Mode to Measurement Mode.
c. The gyro shall perform a health-check at the end of the initialization
phase.
d. The health check shall comprise, as a minimum:
1. communications
2. memories
3. processor function
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4. detector function
NOTE The detector function is a support for failure
diagnosis.
e. The gyro shall be capable to autonomously enter the measurement mode
after power on.
f. It shall be possible to power off the gyro at any time and in any mode of
operation without causing any damage to it.
g. The customer shall specify the transitions between the gyro operational
modes and phases and the transient behaviours.
h. The transition from one operation mode to another one shall not be
automatic, except in case of safety and integrity conditions.
i. A mode status shall be present in the HK data.
j. A reset capacity shall be available and commonly defined by the supplier
and the customer.
4.2.2
...