IEC 61108-7:2024

IEC 61108-7 ®
Edition 1.0 2024-05
INTERNATIONAL
STANDARD
Maritime navigation and radiocommunication equipment and systems – Global
navigation satellite systems (GNSS) –
Part 7: Satellite based augmentation system (SBAS) L1 – Receiver equipment –
Performance standards, methods of testing and required test results

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews, graphical symbols and the glossary.
committee, …). It also gives information on projects, replaced With a subscription you will always have access to up to date
and withdrawn publications. content tailored to your needs.

IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and once
containing more than 22 500 terminological entries in English
a month by email.
and French, with equivalent terms in 25 additional languages.

Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
If you wish to give us your feedback on this publication or need

further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC 61108-7 ®
Edition 1.0 2024-05
INTERNATIONAL
STANDARD
Maritime navigation and radiocommunication equipment and systems – Global

navigation satellite systems (GNSS) –

Part 7: Satellite based augmentation system (SBAS) L1 – Receiver equipment –

Performance standards, methods of testing and required test results

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.060.30; 33.060.20 ISBN 978-2-8322-8555-8

– 2 – IEC 61108-7:2024 © IEC 2024
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 9
2 Normative references . 9
3 Terms, definitions and abbreviated terms . 10
3.1 Terms and definitions . 10
3.2 Abbreviated terms . 11
4 Minimum GNSS and SBAS performance standard . 13
4.1 General . 13
4.2 SBAS L1 receiver equipment . 13
4.2.1 Minimum facilities . 13
4.2.2 Configuration . 14
4.2.3 Quality assurance . 14
4.3 Performance standards for SBAS L1 receiver equipment . 14
4.3.1 General . 14
4.3.2 Equipment output . 14
4.3.3 Accuracy . 16
4.3.4 Acquisition . 17
4.3.5 Availability . 17
4.3.6 Dynamic range . 17
4.3.7 Effects of specific interfering signals . 17
4.3.8 Position update . 18
4.3.9 SBAS input and processing . 18
4.3.10 Navigational status indications . 19
4.3.11 Operation under typical interference conditions . 23
4.3.12 Output of COG, SOG and UTC . 23
5 SBAS technical characteristics . 24
5.1 General . 24
5.2 SBAS L1 SIS RF characteristics . 25
5.3 SBAS L1 SIS message characteristics . 25
5.3.1 Identification . 25
5.3.2 L1 C/A PRN Code for SBAS . 26
5.3.3 SBAS data format . 27
6 Methods of testing and required test results . 28
6.1 Test sites . 28
6.2 Test sequence . 29
6.3 Test signals . 29
6.4 Determination of accuracy . 30
6.5 Environmental conditions . 31
6.6 General requirements . 31
6.7 Alert requirements . 31
6.8 Presentation requirements . 31
6.9 Performance check . 31
6.10 SBAS L1 receiver tests descriptions . 32
6.10.1 SBAS L1 receiver equipment . 32
6.10.2 Configuration . 32

6.10.3 Position output. 32
6.10.4 Equipment output . 32
6.10.5 Static accuracy and availability . 32
6.10.6 Static accuracy with angular movement of the antenna . 33
6.10.7 Dynamic accuracy . 33
6.10.8 Acquisition . 33
6.10.9 Sensitivity and dynamic range . 34
6.10.10 Effects on specific interfering signals . 34
6.10.11 Position update . 34
6.10.12 SBAS input and processing . 35
6.10.13 SBAS message processing . 35
6.10.14 SBAS GEO satellite selection and switching . 38
6.10.15 Navigational status indications . 39
6.10.16 Test for typical interference conditions. 41
6.10.17 Accuracy of COG and SOG. 43
6.10.18 Validity of COG and SOG information . 44
6.10.19 Output of UTC . 44
6.10.20 Validation material for tropospheric model . 44
Annex A (normative) High level procedure for SBAS navigation computation . 45
A.1 GPS L1 signal processing . 45
A.2 SBAS L1 signal processing . 45
A.3 Application of SBAS messages . 45
A.4 SBAS position computation . 47
A.4.1 General . 47
A.4.2 Weighted least squares algorithm . 47
A.4.3 SBAS-based standard residual error . 48
Annex B (normative) Sentences to support SBAS L1 receiver operation . 49
B.1 General . 49
B.2 80GBS – GNSS satellite fault detection . 49
B.3 GFA – GNSS Fix Accuracy and Integrity . 51
B.4 GNS – GNSS fix data . 52
B.5 GRS – GNSS Range residuals . 58
B.6 GSA – GNSS DOP and active satellites . 61
B.7 GSN – GNSS SBAS navigation message . 65
B.8 GSV – GNSS Satellites in View . 66
B.9 RMC – Recommended minimum specific GNSS data . 69
B.10 VTG – Course over ground and ground speed . 71
Annex C (informative) GNSS interference, jamming and spoofing . 72
C.1 General . 72
C.2 Interference . 72
C.3 Jamming . 72
C.4 Spoofing . 73
Annex D (normative) Alert management . 74
Bibliography . 75

Table 1 – Output sentences defined for positioning purposes . 15
Table 2 – Output sentences for integration in other navigational aids . 16

– 4 – IEC 61108-7:2024 © IEC 2024
Table 3 – Required horizontal position accuracy and integrity for general navigation . 19
Table 4 – Accuracy of COG . 24
Table 5 – SBAS L1 SIS RF c
...