IEC 62287-1:2006

Maritime navigation and radiocommunication equipment and systems - Class B shipborne equipment of the automatic identification system (AIS) - Part 1: Carrier-sense time division multiple access (CSTDMA) techniques

Specifies the minimum operational and performance requirements, methods of testing and required test results for Class B shipborne AIS equipment using CSTDMA techniques. Takes into account other associated IEC International Standards and existing national standards. Is applicable for AIS equipment used on craft that are not covered by the mandatory carriage requirement of AIS under SOLAS Chapter V.

General Information

• Status: Published
• Publication Date: 19-Mar-2006
• ICS: 47.020.70 - Navigation and control equipment
• Technical Committee: TC 80 - Maritime navigation and radiocommunication equipment and systems
• Drafting Committee: WG 8A - TC 80/WG 8A
• Current Stage: DELPUB - Deleted Publication
• Start Date: 25-Nov-2010
• Completion Date: 26-Oct-2025

Relations

• Revised: IEC 62287-1:2010 - Maritime navigation and radiocommunication equipment and systems - Class B shipborne equipment of the automatic identification system (AIS) - Part 1: Carrier-sense time division multiple access (CSTDMA) techniques
• Effective Date: 05-Sep-2023

Overview

IEC 62287-1:2006 defines minimum operational and performance requirements, test methods and required test results for Class B shipborne Automatic Identification System (AIS) equipment that use Carrier-Sense Time Division Multiple Access (CSTDMA) techniques. The standard is intended for AIS installations on craft not subject to the SOLAS Chapter V mandatory carriage requirement (for example, smaller or non‑SOLAS vessels). It takes into account associated IEC and national standards to ensure interoperable, safe and testable Class B AIS implementations.

Key Topics and Technical Requirements

• CSTDMA access method: Specifications for carrier-sense timing, slot allocation and channel access to enable coexistence with other AIS users.
• Physical layer requirements: Transmitter and receiver characteristics, modulation and emission masks, frequency and timing tolerances.
• Link, network and transport layers: Message formats, VDL message usage, regional area designation and transport processes for Class B AIS communications.
• GNSS integration: Requirements for onboard GNSS receivers used for position reporting and fallback conditions when position data is unavailable.
• Identification and AIS data: Mandatory identity fields, message contents (e.g., static and dynamic data) and use of flags such as position accuracy.
• User interface, alarms and fall-back: Indicators, initialization procedures, and fall-back arrangements to ensure safe operation.
• Performance and environmental testing: Defined test conditions and procedures covering EMC, vibration/shock, power supply (including undervoltage), receiver sensitivity, intermodulation and conducted spurious emissions.
• Conformance test methods: Detailed operational, physical, link-layer and network-layer test descriptions and pass/fail criteria used by manufacturers and test labs.

Practical Applications and Who Uses This Standard

• Manufacturers and designers of Class B AIS transceivers implement CSTDMA-compliant hardware and firmware to meet performance and interoperability requirements.
• Certification bodies and test laboratories use IEC 62287-1 test methods and results tables to verify compliance prior to market entry.
• Shipyards and system integrators reference the standard when installing AIS on non-SOLAS craft to ensure correct installation, GNSS integration and safety alerts.
• Regulators and port authorities rely on the standard for harmonized technical expectations of Class B AIS devices deployed in coastal and nearshore traffic.

Related Standards

• IEC 62287-1 references and aligns with other IEC international and national maritime standards and applicable regulations (for example, SOLAS Chapter V and relevant ITU recommendations) to ensure compatibility and safe operation across AIS classes.

Keywords: IEC 62287-1, Class B AIS, CSTDMA, AIS testing, maritime navigation, GNSS, TDMA, AIS performance requirements, SOLAS.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 62287-1
First edition
2006-03
Maritime navigation and radiocommunication
equipment and systems –
Class B shipborne equipment of the
automatic identification system (AIS) –
Part 1:
Carrier-sense time division multiple access
(CSTDMA) techniques
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

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edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
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INTERNATIONAL IEC
STANDARD 62287-1
First edition
2006-03
Maritime navigation and radiocommunication
equipment and systems –
Class B shipborne equipment of the
automatic identification system (AIS) –
Part 1:
Carrier-sense time division multiple access
(CSTDMA) techniques
 IEC 2006  Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale XC
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 62287-1  IEC:2006(E)
CONTENTS
FOREWORD.5

INTRODUCTION.7

1 Scope.8

2 Normative references .8

3 Abbreviations .9

4 General requirements .10

4.1 General .10

4.2 Manuals .12
4.3 Marking and identification.12
5 Environmental, power supply, interference and safety requirements .12
6 Performance requirements .13
6.1 Composition .13
6.2 Operating frequency channels .13
6.3 GNSS receiver for position reporting .13
6.4 Identification.14
6.5 AIS information .14
6.6 Alarms and indications, fall-back arrangements.15
6.7 User interface.17
7 Technical requirements .17
7.1 General .17
7.2 Physical layer.18
7.3 Link layer .21
7.4 Network layer .36
7.5 Transport layer.38
7.6 Digital Selective Calling (DSC) .38
8 Test conditions .38
8.1 General .38
8.2 Normal and extreme test conditions.38
8.3 Test signals.39
8.4 Test arrangements .40
9 Power supply, environmental and EMC tests .42
9.1 Test summary .42

9.2 Vibration/shock .43
9.3 Performance tests/checks .44
9.4 Undervoltage test (brown out) .44
10 Operational tests .45
10.1 General .45
10.2 Modes of operation.45
10.3 Messages extending one time period.48
10.4 Channel selection.48
10.5 Internal GNSS receiver.49
10.6 AIS information .49
10.7 Initialisation period .52
10.8 Alarms and indications, fall-back arrangements.52
10.9 User interface.53

62287-1  IEC:2006(E) – 3 –
11 Physical tests .55

11.1 TDMA transmitter .55

11.2 TDMA receivers.59

11.3 Conducted spurious emissions .66

12 Specific tests of link layer.67

12.1 TDMA synchronisation.67

12.2 Carrier-sense tests.68

12.3 VDL state/reservations .70

12.4 Data encoding (bit stuffing) .70

12.5 Frame check sequence .71
12.6 Slot allocation (channel access protocol).71
12.7 Assigned operation.72
12.8 Message formats.73
13 Specific tests of network layer .74
13.1 Regional area designation by VDL message.74
13.2 Regional area designation by serial message or manually.75
13.3 Management of received regional operating settings .75

Annex A (informative) Results of computer simulations and testing of CSTDMA technology.78
Annex B (informative) Description of the system .81
Annex C (normative) DSC channel management.82
Annex D (informative) Channel management regions.89

Figure 1 – OSI layer model .18
Figure 2 – Carrier-Sense timing .22
Figure 3 – Power versus time mask .23
Figure 4 – Transmission packet .24
Figure 5 – Training sequence.26
Figure 6 – Transmission timing .28
Figure 7 – Example for CSTDMA access .29
Figure 8 – Format for repeating four-packet cluster.40
Figure 9 – Measurement arrangement for carrier power .55
Figure 10 – Emission mask .56

Figure 11 – Measurement arrangement for modulation accuracy.57
Figure 12 – Measurement arrangement.59
Figure 13 – Measurement arrangement with two generators .60
Figure 14 – SINAD or PER/BER Measuring Equipment .62
Figure 15 – Measurement arrangement for intermodulation.64
Figure 16 – Configuration for Carrier-Sense threshold test.69
Figure 17 – Regional area scenario .74
Figure A.1 – Effect on Class A AIS messages of Class B messages .78
Figure A.2 – Reception of messages by Class A AIS .79
Figure A.3 – Reception of messages by Class B AIS .79
Figure A.4 – Range achieved by a Class A AIS from Class B AIS. .80
Figure D.1 – Channel management regions used for test given in 13.3.1 .89

– 4 – 62287-1  IEC:2006(E)
Table 1 – Position sensor fallback conditions.16

Table 2 – Use of accuracy (PA) flag.16

Table 3 – Transceiver characteristics.19

Table 4 – Transmitter parameters .20

Table 5 – Receiver parameters .21

Table 6 – Definition of timings for Figure 3.23

Table 7 – Start-buffer.25

Table 8 – Summary of the transmission packet .27

Table 9 – Transmission timing .27
Table 10 – Access parameters.29
Table 11 – Use of VDL messages by a Class B”CS” AIS.32
Table 12 – Number of data bits for use with Message 14 .33
Table 13 – Contents of Message 18.33
Table 14 – Message 24 Part A: .34
Table 15 – Message 24 Part B: .35
Table 16 – Contents of Message 23.35
Table 17 – Reporting Interval Settings for use with Message 23 .36
Table 18 – Channel management .37
Table 19 – Content of first two packets .40
Table 20 – Fixed PRS data derived from ITU-T.O.153 .40
Table 21 – Test summary .42
Table 22 – Peak frequency deviation versus time .58
Table 23 – Frequencies for inter-modulation test .65
Table 24 – Required threshold test results .69
Table 25 – Required carrier sense timing results .70
Table 26 – Required channels in use .75
Table C.1 – DSC monitoring times .83

62287-1  IEC:2006(E) – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
MARITIME NAVIGATION AND RADIOCOMMUNICATION

EQUIPMENT AND SYSTEMS –
CLASS B SHIPBORNE EQUIPMENT OF THE

AUTOMATIC IDENTIFICATION SYSTEM (AIS) –

Part 1: Carrier-sense time division multiple access

(CSTDMA) techniques
FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62287-1 has been prepared by IEC technical committee 80:
Maritime navigation and radiocommunication equipment and systems.
The text of this standard is based on the following documents:
FDIS Report on voting
80/426/FDIS 80/434/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – 62287-1  IEC:2006(E)
IEC 62287 consists of the following parts, under the general title Maritime navigation and

radiocommunication and systems – Class B shipborne equipment of the automatic

identification system (AIS)
Part 1: Carrier-sense time division multiple access (CSTDMA) techniques

Part 2: Self-organising time division multiple access (SOTDMA) techniques

The committee has decided that the contents of this publication will remain unchanged until

the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be

• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

62287-1  IEC:2006(E) – 7 –
INTRODUCTION
In the ITU Radiocommunications Sector Recommendation ITU-R M.1371-1 "Technical

characteristics for a universal shipborne Automatic Identification System (AIS) using SOTDMA

(Self-Organising Time Division Multiple Access) in the VHF maritime mobile band", provision

is made for a Class B AIS for use on craft not covered by a mandatory carriage requirement

under SOLAS Chapter V, Regulation 19. This part of IEC 62287 sets out the requirements,

methods of test and required test results for such a Class B AIS.

The International Maritime Organization (IMO), in its Resolution MSC.140(76), recognised that

the radio channels used by AIS, particularly AIS 1 (161,975 MHz) and AIS 2 (162,025 MHz),

are regarded as an AIS network, and any disruption to those channels by any one AIS device
could affect the operation of all AIS devices on that network. IMO also recognised that
Administrations should take steps necessary to ensure the integrity of the radio channels
used for AIS in their waters.
IEC Technical Committee 80 (TC 80) allocated a new work item 80/287/NP to Working Group
8a (WG 8a), tasking them with producing a test standard for Class B AIS equipment. During
the development of this test standard, Administrations expressed concern that large numbers
of Class B AIS equipped vessels could have a detrimental effect on the safe operation of the
AIS network by SOLAS Class A vessels, Base Stations and AIS on Aids to Navigation (AtoN
AIS). As a result, a new network access technology was developed, which allows large
numbers of Class B fitted vessels to coexist with Class A with a negligible detrimental effect
on AIS network.
The new technology, hereinafter referred to as “Carrier-Sense TDMA (CSTDMA)”, requires
that the Class B“CS”AIS listens to the AIS network to determine if the network is free of
activity and, only if the network is free, can it transmit its information. This Class B AIS is also
required to listen for reservations from base stations and comply with these reservations. This
polite operation ensures that this Class B AIS minimises the probability of interference with
Class A, Base Station or AtoN AIS operations. Extensive computer models simulation and
practical laboratory testing and sea trials were undertaken to validate CSTDMA during its
development (see Annex A).
WG8a recognised that the primary function of a Class B AIS is for fitted vessels to be visible
and participate in the AIS network. CSTDMA was designed to fulfil these requirements.
This Class B AIS is backward compatible with ITU-R Recommendation M.1371-1 (see Annex B).

– 8 – 62287-1  IEC:2006(E)
MARITIME NAVIGATION AND RADIOCOMMUNICATION

EQUIPMENT AND SYSTEMS –
CLASS B SHIPBORNE EQUIPMENT OF THE

AUTOMATIC IDENTIFICATION SYSTEM (AIS) –

Part 1: Carrier-sense time division multiple access

(CSTDMA) techniques
1 Scope
This part of IEC 62287 specifies the minimum operational and performance requirements,
methods of testing and required test results for Class B shipborne AIS equipment using
CSTDMA techniques. This standard takes into account other associated IEC International
Standards and existing national standards, as applicable.
It is applicable for AIS equipment used on craft that are not covered by the mandatory
carriage requirement of AIS under SOLAS Chapter V.
An AIS station intended to operate in receive-only mode shall not be considered a Class B
shipborne mobile AIS station.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60945, Maritime navigation and radiocommunication equipment and systems – General
requirements – Methods of testing and required test results
IEC 61108-1, Maritime navigation and radiocommunication equipment and systems – Global
navigation satellite systems (GNSS) – Part 1: Global positioning system (GPS) – Receiver
equipment – Performance standards, methods of testing and required test results
IEC 61162 (all parts), Maritime navigation and radiocommunication equipment and systems –
Digital interfaces
IEC 61993-1, Maritime navigation and radiocommunication equipment and systems – Part 1:
Shipborne automatic transponder system installation using VHF digital selective calling (DSC)
techniques – Operational and performance requirements, methods of testing and required test
results
IEC 61993-2, Maritime navigation and radiocommunication equipment and systems –
Automatic identification systems (AIS) – Part 2: Class A shipborne equipment of the universal
automatic identification system (AIS) – Operational and performance requirements, methods
of test and required test results
ISO/IEC 3309:1993, Information technology – Telecommunications and information exchange
between systems – High-level data link control (HDLC) procedures – Frame structure
IMO MSC.140(76), Recommendation for the protection of the AIS VHF data link

62287-1  IEC:2006(E) – 9 –
ITU-R Recommendation M.493-11, Digital selective-calling system for use in the maritime

mobile service
ITU-R Recommendation M.825-3, Characteristics of a transponder system using digital

selective calling techniques for use with vessel traffic services and ship-to-ship identification

ITU-R Recommendation M.1084-4, Interim solutions for improved efficiency in the use of the

band 156-174 MHz by stations in the maritime mobile service

ITU-R Recommendation M.1371-1, Technical characteristics for a universal shipborne

automatic identification system using time division multiple access in the VHF maritime mobile

band
ITU-T Recommendation O.153, Basic parameters for the measurement of error performance
at bit rates below the primary rate
3 Abbreviations
AIS Automatic Identification System
BER Bit Error Rate
BT Bandwidth Time product
COG Course over ground
CPU Central Processing Unit
CRC Cyclic Redundancy Check
CS Carrier-Sense
CSTDMA Carrier-Sense Time Division Multiple Access
DGNSS Differential Global Navigation Satellite System
DLS Data Link Service
DSC Digital Selective Calling
ECDIS Electronic Chart Display and Information System
EPFS Electronic Position Fixing System
ETA Estimated Time of Arrival
EUT Equipment Under Test
FCS Frame Check Sequence
FM Frequency Modulation
GMSK Gaussian Minimum Shift Keying
GNSS Global Navigation Satellite System
HDG Heading
HDLC High level Data Link Control
HSC High Speed Craft
IHO International Hydrographic Office
IMO International Maritime Organization
LME Link Management Entity
LR Long Range
MAC Medium Access Control
MMSI Maritime Mobile Service Identity
NM Nautical Miles (refer to ISO 19018)

– 10 – 62287-1  IEC:2006(E)
NRZI Non Return to Zero Inverted

NUC Not Under Command
OSI Open System Interconnection model

P Steady state RF output power
ss
PER Packet Error Rate
PI Presentation Interface
PRS Pseudo Random Sequence
RAIM Receiver Autonomous Integrity Monitoring

RF Radio Frequency
Rx Receive
SINAD Signal Interference Noise and Distortion ratio
SOG Speed Over Ground
SOLAS International Convention for the Safety of Life at Sea
TDMA Time Division Multiple Access
Tx Transmit
UTC Universal Time Co-ordinated
VDL VHF Data Link
VDM Serial output message containing VDL information (IEC 61162-1)
VHF Very High Frequency
VSWR Voltage Standing Wave Ratio
VTS Vessel Traffic Services
NOTE Abbreviations related to IEC 61162 series are not included in the above list. For their meaning refer to that
standard.
4 General requirements
4.1 General
4.1.1 Capabilities of the Class B“CS” AIS
The Class B“CS” AIS shall improve the safety of navigation by assisting in the efficient
navigation of ships and small craft, protection of the environment, and operation of Vessel
Traffic Services (VTS). Small craft are vessels which are not required to comply with the
mandatory carriage requirements of SOLAS Chapter V, Regulation 19.

The Class B“CS” AIS shall be capable of providing information from small craft, automatically,
continuously and with the required accuracy and update rate:
– in a ship-to-ship mode for collision avoidance;
– as a means for littoral States to obtain information about the craft; and
– as a VTS tool, i.e. ship-to-shore (traffic management).
The Class B”CS” AIS station shall be inter-operable and compatible with Class A or other
Class B shipborne mobile AIS stations or any other AIS station operating on the AIS VHF
Data Link. In particular, Class B”CS” AIS stations shall receive other stations, shall be
received by other stations and shall not degrade the integrity of the AIS VHF Data Link.
The Class B”CS” AIS shall only transmit if it has verified that the time period intended for
transmission does not interfere with transmissions made by equipment complying with

62287-1  IEC:2006(E) – 11 –
IEC 61993-2 and from Base Stations. Transmissions of the Class B”CS” AIS shall not exceed

one nominal time period (except when responding to a Base station with Message 19).

4.1.2 Quality assurance
Manufacturers shall have a quality control system audited by a competent authority to ensure

continuous compliance with the requirements of this standard. Alternatively, the manufacturer

may use final product verification procedures where a competent authority verifies compliance

with the requirements of this standard before the product is put to the market.

4.1.3 Safety of operation
It shall not be possible for the operator to augment, amend or erase any program software in
the equipment required for operation in accordance with the equipment standard. Data used
during operation and stored in the system shall be protected in such a way, that necessary
modifications and amendments by the user cannot affect its integrity and correctness.
4.1.4 Additional features
Where equipment provides a facility that is additional to the minimum requirements of this
standard, the operation and, as far as is reasonably practicable, the malfunction of such an
additional facility shall not degrade the performance of the equipment.
4.1.5 Modes of operation
The system shall be capable of operating in a number of modes as described below subject to
the transmission of messages by a competent authority. It shall not retransmit received
messages.
4.1.5.1 Autonomous and continuous mode
An "autonomous and continuous" mode for operation in all areas transmitting Message 18 for
scheduled position reporting and Message 24 for static data.
The Class B”CS” AIS shall be able to receive and process messages at any time except
during time periods of transmission.
4.1.5.2 Assigned mode
An "assigned" mode for operation in an area subject to a competent authority responsible for
traffic monitoring so that the reporting interval, silent mode and/or transceiver behaviour may
be set remotely by that authority using group assignment by Message 23.

4.1.5.3 Interrogation mode
A “polling" or “controlled” mode where the Class B“CS” AIS responds to interrogations by
Messages 18 and 24 from a Class A AIS or a Base Station. A Base Station interrogation for
Message 19 specifying transmission offset shall also be answered . An interrogation
overrides a silent period defined by Message 23 (see 7.3.3.3.3).
A Class B“CS” AIS shall not interrogate other stations.
___________
ISO 9000 series, as applicable, meets this requirement.
Note that because Message 19 is a message occupying two time periods, this requires the reservation of the
respective time periods by Message 20 prior to interrogation.

– 12 – 62287-1  IEC:2006(E)
4.2 Manuals
The manuals shall include:
• the type of external connectors if applicable;

• the required information for correct siting of the antennas;

• the required information for compass safe distance.

4.3 Marking and identification

Each unit of the equipment shall be marked externally with the following information which,
where practicable, shall be clearly visible when the equipment is installed in its recommended
position:
• identification of the manufacturer;
• equipment type number or model identification;
• serial number of the unit;
• power supply requirements; and
• compass safe distance.
Alternatively, the marking may be presented on a display at equipment start-up.
The version of software shall be either marked or displayed on command on the equipment.
When the marking and the title and version of the software are presented only on the display,
such information shall also be included in the equipment manual.
5 Environmental, power supply, interference and safety requirements
In addition to the specific requirements of this standard, the Class B“CS” AIS shall fulfil the
following general requirements as detailed in IEC 60945:
• inter-unit connection (interfaces other than IEC 61162 are allowed; see 6.7.3);
• power supply;
• extreme power supply;
• excessive conditions;
• power supply short-term variation and power supply failure (the Class B“CS” AIS shall not

enter an undefined or unstable state in case of undervoltage);
• durability and resistance to environmental conditions;
• interference;
• electromagnetic compatibility;
• compass safe distance;
• safety precautions;
• protection against accidental access to dangerous voltages;
• electromagnetic radiofrequency radiation;
• X-radiation.
62287-1  IEC:2006(E) – 13 –
The manufacturer shall declare the category of the equipment as follows:

a) portable;
b) protected from the weather;

c) exposed to the weather;
d) submerged or in continuous contact with sea water.

6 Performance requirements
6.1 Composition
The B“CS” AIS shall comprise:
• a communication processor, capable of operating in a part of the VHF Maritime Mobile
Service band, in support of short range (VHF) applications;
• at least one transmitter and three receiving processes, two for TDMA and one for DSC on
channel 70. The DSC process may use the receiving resources on a time-share basis as
described in 7.2.1.6. Outside the DSC receiving periods, the two TDMA receiving
processes shall work independently and simultaneously on AIS channel A and channel B ;
• a means for automatic channel switching in the maritime mobile band (by Message 22 and
DSC). Manual channel switching shall not be provided;
• an internal GNSS position sensor, which provides a resolution of one ten thousandth of a
minute of arc and uses the WGS-84 datum (see 6.3).
6.2 Operating frequency channels
The Class B“CS” AIS shall operate on the frequency channels with 25 kHz bandwidth at least
in the range from 161,500 MHz to 162,025 MHz of the ITU Radio Regulations Appendix 18
and in accordance with ITU-R Recommendation M.1084, Annex 4. The DSC receiving process
shall be tuned to channel 70.
The Class B“CS” AIS shall automatically revert to receive-only mode on the channels AIS 1
and AIS 2 when commanded to change to frequency channels outside its operating range
and/or bandwidth.
6.3 GNSS receiver for position reporting
The Class B“CS” AIS shall have an internal GNSS receiver as a source for position, COG and
SOG.
The internal GNSS receiver shall meet the following requirements of IEC 61108-1:
• position accuracy; static and dynamic (5 s);
• COG/SOG accuracy;
• position update (5 s);
• interference susceptibility, and
• status indications (RAIM optional).
The internal GNSS receiver may be capable of being differentially corrected, for example by
evaluation of Message 17.
___________
In some regions, the competent authority may not require DSC functionality.

– 14 – 62287-1  IEC:2006(E)
An input port for an external GNSS receiver may be provided. The data of an external GNSS

receiver shall only be used if:

• the manufacturer has stated, in the installation handbook, that this equipment shall only be

connected to a position source that is using WGS-84 datum;

• a valid RAIM sentence (GBS) is received and indicates an expected error of less than

10 m in LAT or LON;
• the external position is within 26 m of the internal position, and

• the input format complies with IEC 61162-1 including mode indicator and checksum.

6.4 Identification
For the purpose of ship and message identification, the appropriate Maritime Mobile Service
Identity (MMSI) number shall be used. The unit shall only transmit if an MMSI has been
programmed (see 6.5.1.1).
6.5 AIS information
6.5.1 Information content
The information provided by the Class B“CS” AIS shall include:
6.5.1.1 Static
• Identification (MMSI)
• Name of ship
• Type of ship
• Vendor ID (optional)
• Call sign
• Dimensions of ship and reference for position
The default value for type of ship shall be 37 (pleasure craft). Defaults for other static data
shall be chosen such that it is obvious that the equipment has been properly initialised, in
particular, the default MMSI shall be set to 000000000 and the equipment shall be designed
such that transmissions are inhibited with this default setting (see 6.7.2).
6.5.1.2 Dynamic
• Ship's position with accuracy indication and integrity status
• Time in UTC
• Course over ground (COG)
• Speed over ground (SOG)
• True heading (optional)
6.5.1.3 Configuration information
The following information about configuration and options active in the specific unit shall be
provided:
• AIS Class B”CS” unit;
• availability of minimum keyboard/display facility;
___________
4 Date to be established by receiving equipment.

62287-1  IEC:2006(E) – 15 –
• availability of DSC channel 70 receiver;

• ability to operate in the whole marine band or the upper 525 kHz part of the band (see
6.2);
• ability to process channel management Message 22.

6.5.1.4 Short safety-related messages

Short safety-related messages, if used, shall be in compliance with ITU-R M.1371-1 and shall

use pre-configured contents.
It shall not be possible for the user to alter the pre-configured contents.
6.5.2 Information reporting intervals
The Class B”CS” AIS shall transmit position reports (Message 18) in reporting intervals of
• 30 s if SOG > 2 kn;
• 3 min if SOG ≤ 2 kn
provided that transmission time periods are available. A command received by Message 23
shall override the reporting interval; a reporting interval of less than 5 s is not required.
Static Data submessages 24A and 24B shall be transmitted every 6 min in addition to and
independent of the position report (see 7.4.1). Message 24B shall be transmitted within 1 min
following Message 24A.
6.5.3 Permissible initialisation period
The AIS shall start transmitting position reports within
• cold start: 30 min;
• warm start (if off for less than 1 h): 5 min;
• short signal loss (GNSS signal lost for less than 5 min): resume within a time of twice
the reporting interval.
6.6 Alarms and indications, fall-back arrangements
6.6.1 Integrity and protection
The Class B“CS” AIS shall be equipped with built in integrity tests (BIIT). The BIIT shall run

continuously or at appropriate intervals simultaneously with the standard functions of the
equipment.
If any failure or malfunction is detected that will significantly reduce integrity or stop operation
of the Class B“CS” AIS, a visual indication shall be given (for example a LED, see 6.7.1). This
includes the detection of background noise above –77 dBm (see 7.3.1.3).
The Class B“CS” AIS installation, when operating, shall not be damaged by the effects of
open-circuited or short-circuited antenna terminals.
6.6.2 Transmitter shutdown procedure
An automatic transmitter shutdown shall be provided in the case where a transmitter does not
discontinue its transmission within 1 s of the end of its nominal transmission. This procedure
shall be independent of the operating software.

– 16 – 62287-1  IEC:2006(E)
6.6.3 Position sensor fallback conditions

Priorities and affected position report data (refer to ITU-R M.1371-1 A2/3.3.8.2.1) shall be as

follows:
Table 1 – Position sensor fallback conditions

Affected data in Message 18
Position
Position sensor status
Longitude/Latitude
a
1. External DGNSS in use (corrected) UTC-sec 1/0 * Lat/Lon (external)
1 *
2. Internal DGNSS in use (corrected; Message 17) UTC-sec 1/0 * Lat/Lon (internal)
1 *
c
3. Internal DGNSS in use (corrected; e.g. beacon) UTC-sec 1/0 * Lat/Lon (internal)
1 *
a
4. External GNSS in use (uncorrected) UTC-sec 1/0 * Lat/Lon (external)
0 *
b
5. Internal GNSS in use (uncorrected) UTC-sec 1/0 * Lat/Lon (internal)
0 *
6. No sensor position in Manual position input 61 Do not transmit

use
Dead reckoning position 62 Do not transmit
N/A
N/A
No position 63 Do not transmit

* If RAIM available “1”; if not, default “0”.
a
Applicable only if an input from an external GNSS receiver is provided (see 6.3) which may only be used if the
conditions specified in 6.3 are fulfilled.
b
Applicable in all configurations (minimum requirement).
c
Applicable only if (optionally) an internal beacon receiver is provided.

If RAIM is available (indicated by a valid GBS sentence or equivalent information), the
position accuracy flag shall be evaluated using following table:
Table 2 – Use of accuracy (PA) flag
PA flag RAIM flag
Uncorrected No RAIM, GBS invalid 0 0
GBS valid, expected error <5 m 1 1
GBS valid, expected error >5 m 0 1
Corrected No
...