SIST EN 16605:2025

SLOVENSKI STANDARD
01-februar-2025
Vesolje - Časovni sprejemnik Galileo - Funkcionalne in izvedbene zahteve ter s
tem povezani preskusi
Space - Galileo Timing Receiver - Functional and Performance Requirements and
associated Tests
Raumfahrt - Galileo Timing Receiver - Funktions- und Leistungsanforderungen und
zugehörige Tests
Espace - Récepteur de signaux Galileo pour référence temps - Exigences fonctionnelles
et de performances, et essais associés
Ta slovenski standard je istoveten z: EN 16605:2024
ICS:
33.070.40 Satelit Satellite
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 16605
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2024
ICS 33.070.40
English version
Space - Galileo Timing Receiver - Functional and
Performance Requirements and associated Tests
Espace - Récepteur de signaux Galileo pour référence Raumfahrt - Galileo Timing Receiver - Funktions- und
temps - Exigences fonctionnelles et de performances, Leistungsanforderungen und zugehörige Tests
et essais associés
This European Standard was approved by CEN on 20 September 2024.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom.

CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2024 CEN/CENELEC All rights of exploitation in any form and by any means
Ref. No. EN 16605:2024 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Contents
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 14
4 Galileo Timing Service . 17
4.1 Introduction to timing receivers and timing references . 17
4.2 Galileo Timing Service – Accuracy and Availability . 19
4.3 Galileo Timing Service –Integrity capability . 19
4.3.1 General. 19
4.3.2 Definition of a Fault-Free Timing solution . 19
4.3.3 Definition of a faulty timing solution . 20
4.3.4 High-Level Architecture of Galileo Timing Service . 20
4.3.5 Timing Flags processing . 21
4.3.6 Galileo timing receiver Decision Logic . 22
4.3.7 Time To Alert and Time To Notify . 26
4.3.8 T-RAIM Processing . 26
5 Requirements for Galileo timing receivers . 26
5.1 Definitions . 26
5.2 Minimum Equipment Characteristics . 26
5.3 Functional Requirements . 29
5.3.1 Constellations Processed . 29
5.3.2 Frequencies Processed . 29
5.3.3 Back-up Modes . 29
5.3.4 Dynamics of the User . 29
5.3.5 Time Scales . 30
5.3.6 Processing of Timing Flags and Integrity Requirements . 30
5.3.7 T-RAIM Functional Requirements and Consistency Checks . 35
5.3.8 Anti-Jamming Capabilities . 35
5.3.9 Galileo OS-NMA Processing . 37
5.3.10 Holdover Capabilities . 37
5.3.11 Multipath mitigation . 38
5.3.12 Special Configuration and Output Requirements . 38
5.4 Performance Requirements . 38
5.4.1 General. 38
5.4.2 Accuracy Requirements . 39
5.4.3 Availability Requirements . 39
5.4.4 Integrity Requirements . 40
5.4.5 T-RAIM Performances and thresholds . 42
5.4.6 Holdover Timeout . 42
6 Verification of Galileo timing receivers . 43
6.1 General. 43
6.2 Galileo timing receiver Test Policy . 43
6.3 Strategy for Galileo timing receivers Verification . 44
6.3.1 Verification Methods . 44
6.3.2 Galileo timing receivers Verification Strategy . 44
6.3.3 Galileo timing receiver Test Suite. 45
6.4 Test Environment . 50
6.4.1 General . 50
6.4.2 Record and Replay Test Environment . 50
6.5 Antenna conditions definition . 54
6.5.1 Open sky . 54
6.5.2 Obstructed open sky . 54
6.5.3 Light indoor . 56
6.6 Error Budgets for the Tests . 56
6.7 Traceability Matrix: Requirements vs Verification Method . 57
6.7.1 Traceability . 57
6.7.2 Receiver functionalities Verified by Review Method . 59
6.8 Galileo timing receiver tests . 59
6.8.1 Record and Replay test configuration . 59
6.8.2 Calibration of time delays . 65
6.8.3 For the Verification of Galileo timing receiver Functions (TC-01) . 65
6.8.4 GST Service Level 1 (TC-02) . 67
6.8.5 GST Service Level 2 (TC-03) . 68
6.8.6 GST Service Level 3 (TC-04) . 69
6.8.7 UTC Service Level 1 (TC-05) . 69
6.8.8 UTC Service Level 2 (TC-06) . 70
6.8.9 UTC Service Level 3 (TC-07) . 71
6.8.10 Performances in obstructed environment (TC-08). 72
6.8.11 Performances in light indoor environment (TC-09) . 73
6.8.12 Test on Robustness to Interferences: Nominal Conditions (TC-10) . 73
6.8.13 Test on Robustness to Interferences: Degraded Conditions (TC-11) . 74
6.8.14 Test on T-RAIM Performances (TC-12) . 76
6.8.15 Test on Receiver Noise (TC-13) . 80
Annex A (informative) GNSS Timing Equations . 82
Annex B (informative) Guidelines for Installation and Maintenance . 85
B.1 Antenna, Cabling and Receiver Installation . 85
B.1.1 General . 85
B.1.2 Selecting a GNSS Antenna . 85
B.1.3 Locating and Installing the GNSS Antenna . 86
B.1.4 Connecting to the Antenna: Cabling . 87
B.1.5 Antenna Installation Verification . 87
B.1.6 Using Ancillary Products . 87
B.1.7 Evaluating Signal Attenuation to validate cable length . 87
B.1.8 Multipath Mitigation . 89
B.1.9 Other Recommendations . 89
B.2 Precise computation of the antenna position . 90
B.2.1 General . 90
B.2.2 Needed inputs for conducting a PPP to precisely compute the antenna position of the
Galileo timing receiver . 90
B.2.3 Available online PPP Services . 90
B.3 Initial Calibration of the 1PPS receiver chain time delays. 91
B.4 Periodic re-calibration . 94
Annex C (informative) Record and Replay additional information . 95
C.1 Clock reference sources . 95
Annex D (informative) Timing Flags Definition . 98
Annex E (normative) Provision of Record and Replay files . 101
E.1 Requirements for collecting data for the R&R . 101
E.1.1 Technical documentation . 101
E.1.2 Human resources . 102
E.1.3 GNSS signals digitalization . 102
E.1.4 GNSS constellations simulator . 103
E.2 Requirements for validating R&R data . 104
E.2.1 Validation of the field test . 104
E.2.2 Validation of the digitized GNSS signals . 104
Annex F (informative) Justification of Nominal RFI Environment . 106
Annex G (informative) Validation of Test on Receiver Noise (TC-13) . 107
Bibliography . 108

European foreword
This document (EN 16605:2024) has been prepared by Technical Committee CEN/CLC/JTC 5 “Space”,
the secretariat of which is held by DIN.
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 June 2025, and conflicting national standards shall be
withdrawn at the latest by June 2025.
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.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
The timing capabilities, which are inherent to all GNSS, constitute a paramount benefit allowing the
timing solutions of excellent performance worldwide. Those capabilities have the particularity to be
exploited by sectors which are strategic for the functioning of the modern society. These are the critical
infrastructures such as Telecommunications, Energy and Finance. While timing represents in itself a
small market compared to others if only timing receivers are taken into account, it is an enabler of critical
infrastructures, and thus important for the entire European economy and society. In addition to those
strategic sectors, timing is also used in a wide variety of applications including metrology, remote sensing
and atmosphere research.
The importance of the timing capability has been considered by the European Commission substantial
enough to give it the category of a proper Service in itself as part of the Galileo Service portfolio. This has
been formalized at the level of an EU Regulation [62].
The Service definition undoubtedly starts by taking into account the needs of its intended users and be
flexible to accommodate their evolutions. To that end, stakeholder’s consultations and interactions with
the user community took place and led to the identification of the need to increase robustness and trust
in the timing products. This aspect has then been incorporated as a key feature for the Galileo Timing
Service.
With the Service characteristics and associated performance targets specified, the implementation of the
Service provision implies putting together all the necessary elements to be able to meet those targets and
to ensure that they are maintained over the Service lifetime.
When all is ready, a formal Service declaration informs the users that they can, from then on, rely on it to
develop their own applications.
The Galileo Timing Service concept relies on two fundamental pillars:
— dissemination of information dedicated at timing users, packaged in a Timing Service Message as
part of the Galileo Signal in Space,
— standard for Galileo timing receivers, to ensure that the information provided is adequately
processed as intended and the implementation of local barriers enhancing robustness.
The intent of this document is to specify Requirements and Tests for Galileo timing receivers as part of
the Galileo Timing Service. The target users for the standard are all Galileo Timing users, with special
focus on critical infrastructures and critical applications. The standard takes into account the specificities
of the Galileo Timing Service. This is fundamental in order to ensure the end-to-end performance of the
Galileo Timing Service for those users who make use of a receiver developed according to the standard.
The Galileo Timing Service covers needs and requirements of timing and synchronization for most users,
and it is driven by the critical infrastructure sectors of Energy, Telecom and Finance. The Galileo Timing
Service foresees to support various service monitoring levels accordingly, which is reflected in the
document.
Finally, it is worth recalling that although GNSS receivers are already being used in timing applications –
in particular GPS since it was the first operational GNSS System – there is no associated standard. This
will be then a first, with full support from European Commission, which gives testimony of how serious
the Timing Service is taken into account at EU level.
1 Scope
This document specifies the functional and performance requirements and associated tests for Galileo
timing receivers. The approach for this document is that of a performance based, meaning that no specific
algorithm implementation is required. Instead, performance requirements are specified together with a
corresponding test suite for verification.
This document is applicable to the Galileo chipset. This document does not apply to other sensors and/or
additional processing that a higher synchronization Unit can implement on top of the Galileo chipset.
This document is applicable to the following aspects related to Galileo timing receivers:
— GNSS constellations and frequencies processed: Galileo Dual-Frequency. Other modes are optional,
as explained below;
— time scales, including Galileo System Time and Coordinated Universal Time;
— Services Levels, this document covers the 2 levels of Service for GST and for UTC to be provided by
Galileo Time Service in the first place. The document also anticipates a third Service Level to be
provided in the future, for which an update of the document will be needed;
— user dynamics: fixed users, defined as static users with precise knowledge of the antenna position, is
the baseline mode;
— processing of Timing Service Message disseminated by the Galileo System;
— local timing integrity barriers: As a minimum, Time Receiver Autonomous Integrity Monitoring
processing (T-RAIM);
— robustness to interferences;
— Galileo Open Service Navigation Message Authentication processing;
— robustness to multipath.
This document does not apply to the processing of GPS constellation but this does not preclude
Manufacturers to implement GPS processing within the Galileo timing receivers, even if not addressed in
this document. The use of other GNSS constellations is not forbidden by this document but the
requirements and tests are defined considering Galileo-only, including those related to the integrity of
the timing solution.
This document does not apply to single-frequency modes. This does not preclude manufacturers to
implement single-frequency modes within the Galileo timing receivers, even if not addressed in this
document, as a back-up of the nominal Dual-Frequency mode, and reversion mechanisms. It is important
to remark that the integrity of the timing solution is only specified for Galileo Dual-Frequency mode.
The Galileo timing receivers is only applicable to users operating in static conditions. This document does
not apply to moving users.
On top of the functional requirements, performance requirements are specified in this document in terms
of different key performance indicators such as:
— accuracy, availability and integrity requirements;
— local barriers, T-RAIM performances.
This document also provides the verification matrix and specifies the test suite to verify the most
fundamental requirements of the Galileo timing receivers.
Finally, this document specifies a subclause dedicated to guidelines for the installation and maintenance
of the Galileo timing receivers. This is a comprehensive subclause, including provisions for the antenna,
cabling and receiver installation, as well as the calibration of time delays.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases (see also [43]) for use in standardization at the following
addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1.1
accuracy
degree of conformance of the position, velocity and/or time with the true position, velocity and/or time
of the GNSS user
Note 1 to entry: In the case of this document, the focus is placed on the accuracy of an estimated time, it is measured
in nanoseconds and is provided as a statistic threshold (e.g. 2-sigma). The concept of accuracy in this document is
equivalent to the one in other more general standards such as ISO/IEC Guide 99:2007.
3.1.2
availability
percentage of time that the services of the system are usable by the user
Note 1 to entry: Availability is an indication of the ability of the system to provide usable service within the specified
coverage area. Signal availability is the percentage of time that navigation/timing signals transmitted from external
sources are available for use. It is a function of both the physical characteristics of the environment and the technical
capabilities of the transmitter facilities. Availability is usually expressed in a % of time over a specified period.
Note 2 to entry: Availability = (Number_Epochs_Timing_Service_Available / Total_Number_of_Epochs) * 100
Note 3 to entry: For the particular case of the Availability of the Galileo Timing Service, the Availability concept is
used for the availability of the Service Levels 1, 2 and 3 instead of signal availability.
3.1.3
back-up mode
operational mode of the synchronization unit hosting the Galileo timing receiver in which some of the
functionality and/or input data are not available for the complete performances to be reached, but can
still continue operating under certain functional constraints
3.1.4
Carrier to Noise ratio
C/N0
SNR of a modulated signal consisting of the ratio of the power of the transmitted signal in the passband
frequency over the power of the noise per unit bandwidth, expressed in dB-Hz
3.1.5
dynamic mode
unitless specification of the position/time error propagation as an effect of the satellite position and
pseudorange geometry towards the receiver, considering that solutions calculated using pseudoranges
of close satellites have greater uncertainties compared with solutions calculated using distant satellites
3.1.6
dilution of precision
DOP
dilution of precision is a term used to specify the position/time error propagation as an effect satellite
position and pseudorange geometry towards the receiver. Solutions calculated using pseudoranges of
close satellites have greater uncertainties compared with solutions calculated using distanced satellites.
DOP is unitless
3.1.7
Galileo timing receiver
electronic device, typically a chipset, that processes the Galileo satellite signals captured by an antenna,
to provide accurate time information in the form of PPS signal and accompanying messages
3.1.8
generalist RF test laboratory
laboratory in charge of assessing the performances of the Galileo timing receiver thanks to test scenario
3.1.9
GGTO
GPS-Galileo time offset data, broadcasted by Galileo Satellites, usually expressed in nanoseconds
3.1.10
Global Navigation Satellite System
GNSS
acronym designating satellite positioning systems, being the standard generic term for satellite
navigation systems that provide autonomous geo-spatial positioning with global coverage, including GPS,
GLONASS, Galileo and Beidou
3.1.11
GNSS-specialized laboratory
laboratory in charge of producing test scenarios for generalist RF test laboratories
3.1.12
Galileo System Time
GST
continuous time scale maintained by the Galileo Central Segment and synchronised with TAI
(International Atomic Time) with a nominal offset below 50 ns
3.1.13
holdover
period of time in which two clocks run in an independent way relative to each other after an initial
synchronization
3.1.14
holdover device
device within the synchronization unit which allows the holdover mode
3.1.15
holdover mode
operational mode of the synchronization unit hosting the Galileo timing receiver in which the time is
running based on non-Galileo SIS timing computation from the last or present Epoch
3.1.16
holdover degradation
time and frequency difference between two clocks after the holdover period
3.1.17
holdover timeout
maximum time allowed for the synchronization unit hosting the Galileo timing receiver to work in
holdover mode
Note 1 to entry: The maximum holdover period will depend on the type of local clock – local clock is affected by its
own accuracy, accumulating time error with time - as well as the target Service monitoring level - higher Service
monitoring level implies more stringent accuracy. The Synchronization Unit hosting the Galileo timing receiver
should start counting the holdover time tholdover, from the moment when the switch is performed.
3.1.18
integrity
measure of the trust that can be placed in the correctness of the information supplied by a
navigation/timing system, including the ability of the system to provide timely warnings to users when
the system should not be used for navigation/timing
3.1.19
interference
source of RF transmission that is within the frequency band used by a communication link, and that
degrades the performances of this link
3.1.20
Issue Of Data
IOD
sort of a time stamp on the GNSS data that the receiver gets from the navigation message
3.1.21
jamming
competing signal that prevents the GNSS receiver from decoding the true satellite signal
3.1.22
missed detection
failure in the timing solution, not detected by T-RAIM which does not allow to comply with the intended
service level
3.1.23
Maximum Tolerable Error
MTE
maximum timing error with regard to a certain timescale (UTC or GST) that is expected or acceptable for
the user
3.1.24
navigation message
message transmitted by the GNSS satellites to the users providing all the necessary information to allow
the user to perform the positioning and timing service
3.1.25
performance
extent to which a system is able to meet its output goals
3.1.26
pseudorange
measurement, by the GNSS receiver, of the distance between a satellite antenna and the receiver antenna,
biased by the error due to the difference between the satellite clock and the receiver clock
3.1.27
record & replay
test techniques consisting of digitalizing GNSS signals and sensor measurements in real world campaigns
so that they can be repeated later in suitable laboratory test benches
3.1.28
safety probability of failure
likelihood of a failure of the timing solution during a certain time interval
3.1.29
Signal Noise Ratio
SNR
ratio between signal power to the noise power, normally expressed in dB
3.1.30
spoofing
transmission of signals intended to deceive PVT processing into reporting false PVT target data
3.1.31
static mode
operational mode in which the center of phase of the omnidirectional antenna(s) connected to the Galileo
timing receiver is(are) fixed and the Galileo timing receiver uses an accurately predetermined position
of them for the computation of the time solution
3.1.32
synchronization unit
system of the T&S user hosting the Galileo timing receiver which could comprise other components such
as e.g. a local clock for Holdover Mode, visual interface with the user, etc
3.1.33
holdover time
t
holdover
time interval starting with the instant the synchronization unit hosting the Galileo timing receiver starts
operating in the holdover mode until the present, usually expressed in seconds
3.1.34
International Atomic Time
TAI
time reference coordinate calculated by the Bureau International de l’Heure on the basis of the readings
of atomic clocks operating in various establishments in accordance with the definition of second, the unit
of time of the system of international System of Units (SI), being a coordinate time scale defined in a
geocentric reference frame with a unit increment of 1 s realized on the rotating geoid rotating as the scale
unit
3.1.35
TDOP
dilution of precision for the timing solution, unitless
3.1.36
test scenario
scenario composed of GNSS SIS data resulting from recording activities to assess a Galileo timing receiver
in the desired environments
3.1.37
time error
definition of a failure in timing is provided in 4.3.3
3.1.38
Time Of Day
TOD
sequence describing the hour, minute and second in the current day and which is incremented on the
rising edge of the Galileo timing receiver 1PPS
3.1.39
Time Of Week
TOW
number of seconds, in 20 bits, that have occurred since the transition from the previous week. The TOW
covers an entire week from 0 to 604799 seconds and is reset to zero at the end of each week
3.1.40
Time To Alert
TTA
maximum allowable time elapsed from the onset of an out of tolerance condition (i.e. timing error greater
than MTE) until the equipment enunciates the alert, usually expressed in seconds/minutes
3.1.41
Time To Notify
TTN
notification time required for the system to flag a satellite as don’t use and alert the user, usually
expressed in seconds/minutes
Note 1 to entry: The difference between TTN and TTA is explained in 4.3.7.
3.1.42
Timing RAIM
T-RAIM
user algorithm that determines the integrity of the GNSS solution, being the timing version of RAIM
algorithms applicable to timing receivers
3.1.43
Week Number
WN
12 bits counter that gives the sequential week number from the origin of the Galileo time, covering 4096
weeks (about 78 years), being reset to zero to cover additional period modulo 4096
3.1.44
User Range Error
URE
combination of orbit and clock errors, residual tropospheric error, residual ionospheric error, and local
noise/multipath error, usually expressed in meters
3.1.45
Coordinated Universal Time
UTC
TAI-UTC = n, where n is an integer number of seconds, called leap seconds, created to keep into account
the variable rate of Earth’s rotation rate
Note 1 to entry: As of March 2022, the value of n is 37 s.
3.1.46
UTC Offset
UTCO
offset between the GNSST and UTC, usually expressed in nanoseconds
Note 1 to entry: In the case of Galileo, which is the GNSS constellation addressed in this Standard, the UTC Offset, is
defined for Galileo as the offset between GST and UTC.
3.1.47
UTC(k) laboratory
metrology laboratory maintaining a UTC(k) time scale traceable to UTC
3.1.48
verification
provision of objective evidence that a system satisfies the specified requirement
Note 1 to entry: From ISO GUIDE 99 [68].
3.2 Abbreviated terms
Acronyms used in this document and needing a definition are included in the following table:
Table 1 — Abbreviated terms
Abbreviated Full expression
terms
ADC Analog-to-Digital Converter
ARAIM Advanced Receiver Autonomous Integrity Monitoring
BIPM Bureau International des Poids et Mesures
bUTC_Galileo Prediction of UTC broadcast by Galileo
C/N0 Carrier to Noise ratio
CEN European Committee for Standardization
CENELEC European Committee for Electrotechnical Standardization
CGGTTS Common GNSS Generic Time Transfer Standard
CW Continuous Wave
DF Dual Frequency
DO Disciplined Oscillator
DOP Dilution Of Precision
EC European Commission
ECEF Earth Centered Earth Fixed
EGALITE EGNOS and Galileo Timing Service Extension and Consolidation
EGNOS European Geostationary Navigation Overlay Service
EN European Standard
ESA European Space Agency
ETSI European Telecommunications Standards Institute
FOC Full Operational Capability
FTA Fault Tree Analysis
GGTO GPS-Galileo Time Offset
GMS Galileo Mission Segment
GNSS Global Navigation Satellite System
GNSST GNSS Time
GPS Global Positioning System
GPST GPS Time
GSS Galileo Sensor Stations
GST Galileo System Time
G1G Galileo First Generation
Abbreviated Full expression
terms
G2G Galileo Second Generation
HW Hardware
IBPL Isotropy Based Protection Levels
ICD Interface Control Document
IOD Issue Of Data
IODUTC Issue Of Data Coordinated Universal Time
ITRF International Terrestrial Reference System
ITU International Telecommunication Union
JRC Joint Research Center
KPI Key Performance Indicator
LNA Low Noise Amplifier
LOS Line Of Sight
MJD Modified Julian Day
MOPS Minimum Operational Performance Standard
MTE Maximum Tolerable Error
NLOS Non line Of Sight
NMA Navigation Message Authentication
NMEA National Marine Electronics Association
NTP Network Time Protocol
OCXO Oven-Controlled Crystal Oscillator
OS Open Service
PDOP Position Dilution Of Precision
PHM Passive Hydrogen Masers
PMR Professional Mobile Radio
PMU Phasor Measurement Unit
PPP Precise Point Positioning
PPS Pulse Per Second
PSTN Public Switched Telephone Network
PVT Position Velocity and Time
RAIM Receiver Autonomous Integrity Monitoring
RF Radio Frequency
RFI Radio Frequency Interference
RG Radio Guide
Abbreviated Full expression
terms
RINEX Receiver INdependent EXchange
RSS Root Sum Square
RTCA Radio Technical Commission for Aeronautics
Rx Receiver
R&R Record and Replay
SBAS Satellite Based Augmentation System
SDD Service Definition Document
SDR Software Defined Radio
SF Single Frequency
SHS Signal Health Status
SI Système International d'unités (International System of Units)
SIS Signal In Space
SISA Signal In Space Accuracy
SL Service Level
SNR Signal-to-Noise Ratio
SPS Symbols Per Second
STARLITE Preparation of standards for Galileo timing receivers
SVID Space Vehicle Identification
T-ARAIM Timing ARAIM
T-IBPL Timing IBPL
T-RAIM Timing RAIM
TAI International Atomic Time
TBC To Be Confirmed
TBD To Be Defined
TC Test Case
TDOP Time Dilution of Precision
TE Time Error
TESLA Timed Efficient Stream Loss-tolerant Authentication
TGD Time Group Delay
TIC Time Interval Counter
TOD Time Of Day
TOW Time Of Week
TS Tender Specifications
Abbreviated Full expression
terms
TSM Timing Service Monitoring
TTA Time To Alert
TTFF Time To First Fix
TTL Transistor-Transistor Logic
TTN Time To Notify
T&S Time and Synchronization
UART Universal Asynchronous Receiver-Transmitter
UCP User Consultation Platform
UI User Interface
URE User Range Error
USB Universal Serial Bus
USRP Universal Software Radio Peripheral
UTC Coordinated Universal Time
UTCO UTC Offset
UV Ultraviolet
VLBI Very Long Baseline Interferometry
WG Working Group
WN Week Number
WP Work Package
4 Galileo Timing Service
4.1 Introduction to timing receivers and timing references
This subclause provides an introduction to timing receivers and timing references, including the Pulse-
Per-Second and Time Of Day generation in timing receivers. This document is focused on the Galileo
chipset, also called “Galileo timing receiver”. The Galileo timing receiver is hosted by a synchronization
unit, which could comprise other components such as e.g. a local clock for Holdover Mode, visual interface
with the user, etc.
There are two relevant time references in the frame of Galileo Timing Service: the Galileo System Time
(GST), and the Coordinated Universal Time (UTC). For the latter, Galileo broadcast in the Signal in Space
the offset between GST and a realization of UTC obtained through a Timing Service Provider as
combination of several European national UTC(k) time scales.
The mathematical foundation of GNSS timing can be found in Annex A of this document.
A GNSS timi
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