ISO 22090-2:2014

INTERNATIONAL ISO
STANDARD 22090-2
Second edition
2014-03-01
Ships and marine technology —
Transmitting heading devices
(THDs) —
Part 2:
Geomagnetic principles
Navires et technologie maritime — Dispositifs de transmission de
données de pilotage —
Partie 2: Principes géomagnétiques
Reference number
©
ISO 2014
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Performance requirements . 3
4.1 Functionality . 3
4.2 Information . 3
4.3 Fore-and-aft mark . 4
4.4 Heading information . 4
4.5 Electrical wiring . 4
4.6 Non-magnetic housing . 4
4.7 Alert signal . 4
4.8 Interface . 4
5 Accuracy . 5
5.1 General . 5
5.2 Accuracy of transmission data . 5
5.3 Static error (settle point error) . 5
5.4 Dynamic error . 5
5.5 Follow-up error . 5
5.6 Settling time requirements to the directional system. 5
5.7 Correcting the magnetic heading by magnetic variations . 5
5.8 Adjusting of magnetic deviations and heeling error . 5
5.9 Means of adjusting the deviation by vertical soft iron of the ship . 6
5.10 Protection of correcting devices . 6
6 Type tests . 6
6.1 General . 6
6.2 Transmission error test . 6
6.3 Fore-and-aft mark test. 7
6.4 Static error test . 7
6.5 Follow-up error test . 7
6.6 Settling time test . 7
6.7 Tests for correcting the magnetic heading by magnetic variations . 7
6.8 Tests for adjusting magnetic deviations . 8
6.9 Tests for the means of adjusting the deviation by vertical soft iron . 8
6.10 Dynamic accuracy . 8
6.11 Interface test . 8
6.12 Malfunction test . 8
7 Marking and identification . 8
Annex A (informative) Equivalent requirements in ISO 22090-2 and IMO Resolution MSC.116(73).
Bibliography .11
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 8, Ships and marine technology, Subcommittee
SC 6, Navigation and ship operations.
This second edition cancels and replaces the first edition (ISO 22090-2:2004), which has been technically
revised. It also replaces ISO 22090-2:2004/Cor1:2005.
ISO 22090 consists of the following parts, under the general title Ships and marine technology —
Transmitting heading devices (THDs):
— Part 1: Gyro-compasses
— Part 2: Geomagnetic principles
— Part 3: GNSS principles
iv © ISO 2014 – All rights reserved

INTERNATIONAL STANDARD ISO 22090-2:2014(E)
Ships and marine technology — Transmitting heading
devices (THDs) —
Part 2:
Geomagnetic principles
1 Scope
This part of ISO 22090 specifies the construction, performance, and testing of a device employing only
magnetic means as transmitting heading devices required by chapter V, SOLAS 1974 (as amended).
A Transmitting Heading Device (THD) is an electronic device that provides information about the ship’s true
heading.
In addition to the general requirements contained in IMO Resolution A.694(17) to which IEC 60945 is
associated and the relevant standard for the sensing part used, the THD equipment shall comply with the
following minimum requirements.
Where the IMO performance standards which apply to the sensing part do not specify a geographical
operating area the THD shall operate
a) at a minimum rate of turn 20 °/s and
b) from 70° latitude south to 70° latitude north as a minimum.
The THDs complying with the requirements contained in this part of ISO 22090 can be used for heading
information as contained in chapter V of the SOLAS Convention.
In addition such THDs are intended to meet the dynamic requirements contained in the HSC Code, chapter
13 for the carriage of a suitable device providing heading information.
NOTE 1 Several technologies can be used to detect and transmit heading information. It is illogical to
standardize the detection of the heading separately from the transmission of the heading. Therefore, separate
parts of this part of ISO 22090 refer to different technologies. The requirements of this part of ISO 22090 only
apply to the principle of the geomagnetic. Other technologies are covered in other parts of ISO 22090.
NOTE 2 All requirements that are extracted from the recommendation of IMO Resolution MSC.116(73) on
performance standards for transmitting heading devices are printed in italics.
A standard magnetic compass with a pickup sensor could be applied as a sensing part of this standard
of geomagnetic principle. However the IMO performance resolution MSC.116(73) requires that the THD
is intended to be met for the dynamic requirements of the HSC code. Nevertheless, when the THD would
be only used other than the HSC, the limit of rate of turn may be 6 °/s instead of 20 °/s.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 11606, Ships and marine technology — Marine electromagnetic compasses
ISO 25862, Ships and marine technology — Marine magnetic compasses, binnacles and azimuth reading
devices
IEC 60945, Marine navigation and radiocommunication equipment and systems – General requirements –
Methods of testing and required test results
IEC 61162-1, Marine navigation and radiocommunication equipment and systems – Digital interfaces – Part
1: Single talker and multiple listeners
IEC 61162-2, Maritime navigation and radiocommunication equipment and systems – Digital interfaces –
Part 2: Single talker and multiple listeners, high-speed transmission
IEC 61924-2, Maritime navigation and radiocommunication equipment and systems – Integrated Navigation
Systems (INS) – Part 2: Modular struct
...