IEC 62320-1:2007
(Main)Maritime navigation and radiocommunication equipment and systems - Automatic identification system (AIS) - Part 1: AIS Base Stations - Minimum operational and performance requirements, methods of testing and required test results
Maritime navigation and radiocommunication equipment and systems - Automatic identification system (AIS) - Part 1: AIS Base Stations - Minimum operational and performance requirements, methods of testing and required test results
Specifies the minimum operational and performance requirements, methods of testing and required test results for AIS Base Stations, compatible with the performance standards adopted by IMO Res. MSC.74 (69), Annex 3, Universal AIS. It incorporates the technical characteristics of non-shipborne, fixed station AIS equipment, included in the relevant ITU and IALA recommendations. Where applicable, takes into account the ITU Radio Regulations.
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INTERNATIONAL IEC
STANDARD 62320-1
First edition
2007-02
Maritime navigation and radiocommunication
equipment and systems –
Automatic identification system (AIS) –
Part 1:
AIS Base Stations –
Minimum operational and performance
requirements, methods of testing and
required test results
Reference number
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INTERNATIONAL IEC
STANDARD 62320-1
First edition
2007-02
Maritime navigation and radiocommunication
equipment and systems –
Automatic identification system (AIS) –
Part 1:
AIS Base Stations –
Minimum operational and performance
requirements, methods of testing and
required test results
© IEC 2007 ⎯ 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: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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For price, see current catalogue
– 2 – 62320-1 © IEC:2007(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Symbols and abbreviations.8
4 Functional layout of an AIS Base Station .8
4.1 General .8
4.2 Functional block diagram of an AIS Base Station.9
4.3 General VDL requirements .10
4.4 Functional diagram for operation of a Base Station .11
4.5 Base Station input/output sentence formatters.11
5 Functional definition of the radio interface of the AIS Base Station .13
5.1 General requirements of the physical layer.13
5.2 Required parameter settings for the physical layer of the AIS Base Station .13
5.3 Minimum requirements for the TDMA transmitter of the AIS Base Station.14
5.4 Minimum requirements for the TDMA receivers of the AIS Base Station .15
5.5 Shutdown procedure for an AIS Base Station .15
6 Requirements for AIS Base Station.15
6.1 General .15
6.2 Dependent Base Station requirements.16
6.3 Independent Base Station requirements .17
6.4 BIIT conditions .22
6.5 Further requirements for optional features.22
7 Functional definition of the presentation interface of the AIS Base Station.23
7.1 Physical requirements for the presentation interface .23
7.2 Presentation interface data exchange.23
8 Tests of AIS Base Stations – method of measurement and required results.24
8.1 Test conditions.24
9 Physical radio tests .27
9.1 Transceiver protection test .27
9.2 TDMA transmitter .28
9.3 TDMA receivers.35
9.4 Conducted spurious emissions at the antenna.43
10 Functional tests for Base Station .44
10.1 Pre-set-up .44
10.2 Normal operation.45
10.3 Intentional slot reuse (link congestion) .72
10.4 Comment Block Encapsulation .73
Annex A (informative) Proposed additional IEC 61162 AIS sentences.75
Figure 1 – Functional block diagram of an AIS Base Station .9
Figure 2 – Functional block diagram dependent and independent operation.11
Figure 3 – General processing diagram .17
Figure 4 – General processing diagram .18
62320-1 © IEC:2007(E) – 3 –
Figure 5 – Flow diagram for AIS Base Station response to VDM input.21
Figure 6 – Format for repeating four-packet cluster.25
Figure 7 – Measurement arrangement .28
Figure 8 – Measurement arrangement .29
Figure 9 – Modulation spectrum for slotted transmission 25 kHz .30
Figure 10 – Modulation spectrum for slotted transmission at optional 12,5 kHz .31
Figure 11 – Measurement arrangement for modulation accuracy.31
Figure 12 – Power versus time mask .33
Figure 13 – Measurement arrangement.34
Figure 14 – Measurement arrangement.35
Figure 15 – Measurement arrangement.36
Figure 16 – Measurement arrangement.37
Figure 17 – Measurement arrangement.38
Figure 18 – PER/BER or SINAD measuring equipment .40
Figure 19 – Measurement arrangement for inter-modulation .42
Figure 20 – Measurement arrangement for blocking or de-sensitisation .43
Table 1 – Base Station input/output sentence formatters .12
Table 2 – Required parameter settings for an AIS Base Station .14
Table 3 – Required settings of physical layer constants .14
Table 4 – Bandwidth related parameters of the physical layer of the AIS Base Station.14
Table 5 – Minimum required TDMA transmitter characteristics .15
Table 6 – Minimum TDMA receiver characteristics .15
Table 7 – Base Station response to input messages from the VDL.17
Table 8 – Base Station response to input messages from the VDL.19
Table 9 – BIIT alarm conditions monitored by an AIS Base Station .22
Table 10 – Content of first two packets .25
Table 11 – Fixed PRS data derived from ITU-T O.153 .25
Table 12 – Maximum values of absolute measurement uncertainties.27
Table 13 – Definition of timings for Figure 12.33
Table 14 – Frequencies for inter-modulation tests.42
– 4 – 62320-1 © IEC:2007(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
MARITIME NAVIGATION AND RADIOCOMMUNICATION
EQUIPMENT AND SYSTEMS –
AUTOMATIC IDENTIFICATION SYSTEM (AIS) –
Part 1: AIS Base Stations –
Minimum operational and performance requirements,
methods of testing and required test results
FOREWORD
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tions.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
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 62320-1 has been prepared by IEC Technical Committee 80: Mari-
time navigation and radiocommunication equipment and systems.
The text of this standard is based on the following documents:
FDIS Report on voting
80/460/FDIS 80/468/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.
62320-1 © IEC:2007(E) – 5 –
A list of all parts of IEC 62320 series, under the general title: Maritime navigation and radio-
communication equipment and systems – Automatic Identification System (AIS) can be found
on the IEC website.
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.
– 6 – 62320-1 © IEC:2007(E)
INTRODUCTION
Chapter V of the International Convention for the Safety of Life at Sea 1974 (SOLAS) requires
mandatory carriage of Automatic Identification System (AIS) equipment on all vessels con-
structed on or after 01 July 2002. Carriage for other types and sizes of SOLAS Convention
vessels was required to be completed not later than 31 December 2004.
SOLAS Chapter V, Regulation 19, clause 2.4.5 states that AIS shall:
1 provide automatically to appropriate equipped shore stations, other ships and aircraft in-
formation, including ship's identity, type, position, course, speed, navigational status and
other safety-related information;
2 receive automatically such information from similarly fitted ships;
3 monitor and track ships; and
4 exchange data with shore-based facilities.
In addition, the IMO performance standards for AIS state that:
– The AIS should improve the safety of navigation by assisting in the efficient navigation of
ships, protection of the environment, and operation of Vessel Traffic Services (VTS), by
satisfying the following functional requirements:
1 in a ship-to-ship mode for collision avoidance;
2 as a means for littoral States to obtain information about a ship and its cargo; and
3 as a VTS tool, i.e. ship-to-shore (traffic management).
– The AIS should be capable of providing to ships and to competent authorities, information
from the ship, automatically and with the required accuracy and frequency, to facilitate ac-
curate tracking. Transmission of the data should be with the minimum involvement of
ship's personnel and with a high level of availability.
The provision of Shore Based AIS will be necessary to attain the full benefit of the SOLAS
Convention requirements.
This part of IEC 62320 provides the minimum operational and performance requirements,
methods of test and the required test results for AIS Base Stations. The testing is divided into
three sections, the transceiver tests, the logical tests and the Presentation Interface tests.
These are captured in Clauses 8, 9 and 10 respectively. The method used for testing is that
the EUT should meet all the tests requirements of Clause 8 before proceeding to Clause 9.
Likewise, the unit should meet all of the test requirements before proceeding to Clause 10.
Clause 10 has also been prioritised so that the tests are progressive
Clauses 5 to 7 provide functional requirement information and Clause 8 provides the general
test environment for the EUT.
62320-1 © IEC:2007(E) – 7 –
MARITIME NAVIGATION AND RADIOCOMMUNICATION
EQUIPMENT AND SYSTEMS –
AUTOMATIC IDENTIFICATION SYSTEM (AIS) –
Part 1: AIS Base Stations –
Minimum operational and performance requirements,
methods of testing and required test results
1 Scope
This part of IEC 62320 specifies the minimum operational and performance requirements,
methods of testing and required test results for AIS Base Stations, compatible with the per-
formance standards adopted by IMO Res. MSC.74 (69), Annex 3, Universal AIS. It incorpo-
rates the technical characteristics of non-shipborne, fixed station AIS equipment, included in
recommendation ITU-R M.1371 and IALA Recommendation A-124. Where applicable, it also
takes into account the ITU Radio Regulations. This standard takes into account other associ-
ated IEC international standards and existing national standards, as applicable.
This standard is applicable for AIS Base Stations. It does not include specifications for the
display of AIS data on shore.
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 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 61162-1, Maritime navigation and radiocommunication equipment and systems – Digital
interfaces – Part 1: Single talker and multiple listeners
ITU-R 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 M.1371, Technical characteristics for an automatic identification system using time di-
vision multiple access in the VHF maritime mobile band
ITU-T O.153, Basic parameters for the measurement of error performance at bit rates below
the primary rate
IALA Recommendation A-124 on Automatic Identification System (AIS). Shore Station and
networking aspects relating to the AIS Service
IALA technical clarifications to ITU Recommendation ITU-R M.1371-1
RTCM SC104 – RTCM Recommended Standards for Differential GNSS (Global Navigation
Satellite Systems) Service
– 8 – 62320-1 © IEC:2007(E)
3 Symbols and abbreviations
AIS Automatic Identification System
BER Bit Error Rate
BIIT Built-In Integrity Tests
BT Bandwidth Time product
CPU Central Processing Unit
DGNSS Differential Global Navigation Satellite System
EPFS Electronic position fixing system
EUT Equipment under test
FATDMA Fixed Access Time Division Multiple Access
GNSS Global Navigation Satellite System
IALA International Association of Marine Aids to Navigation and Lighthouse Authorities
IHO International Hydrographic Office
IMO International Maritime Organization
ITU International Telecommunications Union
kn Knots
MAC Medium Access Control
MKD Minimum Keyboard and Display
MMSI Maritime Mobile Service Identity
NM Nautical Mile
NRZI Non-Return to Zero Inverted
PER Packet Error Rate
P Carrier Power
c
PI Presentation Interface
PPS Pulse Per Second
PSS Physical Shore Station
RAIM Receiver Autonomous Integrity Monitoring
RATDMA Random Access Time Division Multiple Access
Rx Receive
TDMA Time Division Multiple Access
Tx Transmit
UTC Universal Time Co-ordinated
VDL VHF Data Link
VSWR Voltage Standing Wave Ratio
VTS Vessel Traffic Services
NOTE Abbreviations related to IEC 61162-1 are not included in the above list. For their meaning refer to that
standard and Annex A.
4 Functional layout of an AIS Base Station
4.1 General
The Base Station may be designed for dependent only operation or independent operation.
Both are under some control of the Physical Shore Station (PSS) as defined in the IALA Rec-
ommendation A-124.
62320-1 © IEC:2007(E) – 9 –
– A dependent Base Station accesses the VHF data link (VDL) using only the combination of
linked TSA+VDM sentences (see Table 1), as provided by the PSS.
– An independent Base Station accesses the VDL using either the combination of linked
TSA+VDM sentences as provided by the PSS or by using internal control. When operated
as an independent Base Station the unit may be delegated certain autonomous functional-
ity under the supervisory control of the PSS.
The PSS, or external controlling entity, is responsible for Base Station configuration, trans-
mission scheduling, and processing of received information. Presentation Interface (PI) text
sentences are used to configure the Base Station, schedule message transmissions, and out-
put information.
When TSA and VDM sentences are used, the PSS is responsible for ensuring the integrity of
the VDL.
The tests in this standard are for all Base Stations. Additional tests for independent Base Sta-
tions are indicated by a note located at the beginning of each appropriate test section.
4.2 Functional block diagram of an AIS Base Station
Figure 1 shows the principal components of the AIS Base Station.
AIS Base Station
AIS TX
I/O
Controller
Options
Internal
Ext UTC
synchronisation
sync
source
DGNSS
AIS RX
RTCM SC104
BIIT
AIS RX
Power supply
IEC 150/07
Figure 1 – Functional block diagram of an AIS Base Station
As a minimum, the following functional elements are required for the AIS Base Station:
• two multi-channel receivers;
• one multi-channel TDMA transmitter;
NOTE Since the minimum configuration of the AIS Base Station has only one transmitter, the AIS Base Sta-
tion cannot transmit on both AIS Channels (AIS A and AIS B) simultaneously.
• a controlling unit;
• an internal synchronisation source, which may also be used as a position sensor for inde-
pendent Base Stations. If used as a position source, the internal GNSS receiver shall
meet the appropriate requirements of IEC 61108-1;
• a Built-In-Integrity-Test unit (BIIT), which shall provide alarms;
Presentation interface
– 10 – 62320-1 © IEC:2007(E)
• a power supply;
• a Presentation Interface (PI), which allows the AIS Base Station to exchange sentences
with the PSS;
• optional features, for example: DGNSS (RTCM SC104); external synchronisation; DSC
functionality.
4.3 General VDL requirements
The AIS Base Station interacts with the VDL by receiving and transmitting VDL messages.
4.3.1 Sources of VDL messages for transmission
In order to transmit VDL messages, the Base Station may derive the messages to be transmit-
ted from three sources:
a) generate and transmit VDL messages autonomously as per the configuration received via
sentences;
b) generate and transmit VDL messages automatically based on data input received via the
PI, using different sentences from that of the VDM;
c) transmit predefined VDL messages input via the PI. The VDM sentence shall be used to
input the content of the VDL messages via the PI to the AIS Base Station. The VDL mes-
sage shall then be transmitted by the Base Station on the VDL.
When operating the Base Station independently, these three VDL message sources shall be
supported in parallel.
When operating the Base Station dependently, only VDM messages received via the PI shall
be transmitted as noted in item c) above.
4.3.2 Use of access schemes
4.3.2.1 Dependent operation
When operating as a dependent Base Station the FATDMA access scheme shall be used. The
Base Station shall use the slot(s) provided by the combination of linked TSA+VDM sentences.
The TSA sentence provides the channel and start slot information. The actual number of slots
used is based on the number of bits conveyed by the VDM sentence(s).
Dependent operation shall not use the RATDMA access scheme
4.3.2.2 Independent operation
The default access scheme for a Base Station shall be FATDMA.
The AIS Base Station may also use RATDMA access schemes if implemented. The AIS Base
Station may use the FATDMA and RATDMA access schemes concurrently. The use of pre-
reserved FATDMA slots shall take priority over RATDMA access.
When using the FATDMA access scheme, the absolute slot numbers for transmission shall be
determined by one of the following methods:
• the PI combination of linked TSA+VDM sentences shall provide the absolute slot number
in which the AIS Base Station transmits;
• the AIS Base Station shall autonomously select an appropriate pre-reserved FATDMA slot
as determined by its configuration.
Both methods shall be available and operate concurrently.
62320-1 © IEC:2007(E) – 11 –
4.4 Functional diagram for operation of a Base Station
Figure 2 shows the principal components of an AIS Base Station. The diagram identifies the
elements of the AIS Base Station and the PI with the PSS.
Physical
External message
Shore
processing and generation
TSA+VDM
Station
Presentation Interface I/O
DGNSS
ALR PI-input
ABK
(RTCM)
TXT and Table 1
queries
Autonomous message
Base Base Station configuration
processing and generation
and management
Station
VDO
TFR
VSI
UTC
sync VDL
mesage
source
Time (slot)
VDL SYNC
TIME
queue
reference
information UTC
control
process
indirect and
VDM
semaphore
FSR
VSI
Slot timing reference
Rx process Tx process
VDL
message
IEC 151/07
Figure 2 – Functional block diagram dependent and independent operation
The PI of an AIS Base Station consists of at least one input/output port. A specific choice for
the physical input/output port is not specified. The purpose of the PI is to:
• exchange VDL messages with the PSS;
• configure the Base Station;
• enable real time control of the Base Station;
• provide an output for BIIT alarms and status.
The information exchange of the PI is supported by a combination of IEC 61162-1 sentences
and Base Station sentences (see Annex A).
4.5 Base Station input/output sentence formatters
The following table lists sentence formatters used with a Base Station. It includes existing
sentence formatters (grey rows) and sentence formatters developed for use with Base Sta-
tions (white rows). Clause A.1 contains the details for each of the sentence formats developed
for AIS Base Stations.
A sentence linking method is described in Annex A.2. Use of this method improves the integ-
rity of data relationships between sentences, and improves the reliability and clarity of com-
munications with the Base Station.
– 12 – 62320-1 © IEC:2007(E)
Table 1 presents both input and output sentence formatters for dependent and independent
operation. For Base Stations that support both independent and dependent operation, both
sets of sentences are applicable. For Base Stations that only support dependent operation,
the sentences for dependent operation are applicable and all other sentences are ignored.
Table 1 – Base Station input/output sentence formatters
Sentence Input Input Output Output
Description
formatter independent dependent independent dependent
Addressed and binary broadcast
ABK X
acknowledgement
Addressed binary and safety re-
ABM X
lated message
AIS regional channel assignment
ACA X Q
message
Preparation and initiation of an
AIS Base Station addressed
ACM X
channel message (VDL Message
22)
ACK X X Acknowledge alarm
AIS Device Status (output interval
ADS X X
configured by BCE and upon
status change)
Preparation and Initiation of an
AIS Base Station broadcast of a
AGA X
group assignment message
(Message 23).
ALR X X Set alarm state
AIS interrogation request (VDL
AIR X
Message 15)
Preparation and initiation of an
ASN X
AIS Base Station broadcast of
assignment VDL Message 16
BBM X Broadcast binary message
General Base Station
BCE X X Q Q
configuration extended
General Base Station
BCF X X Q Q
configuration
CAB X X Q Q Control AIS Base Station
Not supported by this IEC
CBM
standard
Data Link Management slot
allocations for Base Station (VDL
DLM X Q
Message 20 – FATDMA
reservations)
Configure broadcast rates for
ECB X Q Base Station messages with
epoch planning support
Frame summary of AIS reception,
FSR X X
defined by SPO.
Installation of a station’s
SID X X
identification
Select AIS device’s reception
SPO X X Q Q
processing and output
62320-1 © IEC:2007(E) – 13 –
Table 1 (continued)
Sentence Input Input Output Output
Description
formatter independent dependent independent dependent
Transmit feed-back report – Base
Station report on status of
TFR X X
requested transmission. Automatic
status response of TSA+VDM.
Transmit Slot Assignment – used
to identify AIS time slot used to
TSA X X
transmit the content of a VDM
sentence
TSP X Transmit Slot Prohibit
Transmit Slot Prohibit status
TSR X Report. Automatic status response
of TSP.
VDM X X X X VHF Data-link message
VHF Data-link Own-vessel mes-
VDO X X
sage
Version information about equip-
VER Q Q ment. Provided in response to
ABQ.
VDL Signal Information, defined
VSI X X
by SPO.
NOTE 1 “X” indicates input to, or output from, the AIS Base Station. “Q” indicates that the sentence may be ex-
ternally requested using the IEC 61162-1 “$xxABQ,xxx” query sentence (See Annex A) method(s) in order for the
identified sentence to be output.
NOTE 2 Sentence formatters shown in shaded rows are described in IEC 61162-1.
The AIS Base Station shall output, autonomously and periodically, the ADS sentence on the
PI indicating the Base Station status. This shall be output once per minute or when there is a
change in the status.
5 Functional definition of the radio interface of the AIS Base Station
The physical layer of the AIS Base Station shall be designed in accordance with the following
minimum requirements.
5.1 General requirements of the physical layer
The following general requirements apply to all receivers and transmitter:
• a Base Station shall use simplex channels or duplex channels in either full-duplex or half-
duplex mode;
• a Base Station shall be capable of 25 kHz and, optionally, 12,5 kHz emission/reception in
accordance with ITU-R M.1084-4, Annex 3 (as referenced by Recommendation ITU-R
M.1371);
• a Base Station shall be capable of transmitting using at least two different power settings,
as provided for by ITU-R M.1371 and IALA technical clarifications to ITU-R M.1371. The
Base Station shall have the capability to set its power level as stipulated by an input com-
mand.
5.2 Required parameter settings for the physical layer of the AIS Base Station
Table 2, Table 3 and Table 4 are derived from Recommendation ITU-R M.1371 and give the
parameters required for an AIS Base Station.
– 14 – 62320-1 © IEC:2007(E)
NOTE For the meaning of the symbols and additional information refer to the appropriate clause of Recommenda-
tion ITU-R M.1371.
The constants of the physical layer of the AIS Base Station shall comply with the values given
in Table 3 and Table 4.
Table 2 – Required parameter settings for an AIS Base Station
Symbol Parameter name Low setting High setting
PH.RFR Regional frequencies 156,025 MHz 162,025 MHz
PH.CHS Channel spacing 12,5 kHz Optional 25 kHz
PH.AIS1 AIS 1 (default channel 1) 161,975 MHz 161,975 MHz
PH.AIS2 AIS 2 (default channel 2) 162,025 MHz 162,025 MHz
PH.CHB Channel bandwidth 12,5 kHz 25 kHz
Narrow Optional Wide
PH.BR Bit rate 9 600 bps 9 600 bps
PH.TS Training sequence Always start with a zero 24 bits 24 bits
(0101010…)
PH.TST Transmitter settling time (Transmit power within 20 %
≤ 1,0 ms ≤ 1,0 ms
of final value, frequency stable to within ± 1,0 kHz of
final value)
Table 3 – Required settings of physical layer constants
Symbol Parameter name Value
PH.DE Data encoding NRZI
PH.FEC Forward error correction Not used
PH.IL Interleaving Not used
PH.BS Bit scrambling Not used
PH.MOD Modulation Bandwidth adapted; GMSK (see Table 4)
Table 4 – Bandwidth related parameters of the physical layer of the AIS Base Station
Symbol Parameter name PH.CHB/narrow PH.CHB/wide
PH.TXBT Transmit BT-product 0,3 0,4
PH.RXBT Receive BT-product 0,3 0,5
PH.MI Modulation index 0,25 0,50
5.3 Minimum requirements for the TDMA transmitter of the AIS Base Station
The minimum technical characteristics as specified in Table 5 shall apply to the TDMA trans-
mitters.
62320-1 © IEC:2007(E) – 15 –
Table 5 – Minimum required TDMA transmitter characteristics
Transmitter parameters 25 kHz channels 12,5 kHz channels
Carrier power error
± 1,5 dB ± 1,5 dB
Carrier frequency error ± 500 Hz ± 500 Hz
Slotted modulation mask
–25 dBc at ± 10 kHz 0 dBc at ± 2,5 kHz
–70 dBc at ± 25 kHz –60 dBc at ± 12,5 kHz
Transmitter test sequence and modulation accuracy ‘0’ bit start for test sig- ‘0’ bit start for test signals
nals 1 and 2 1 and 2
1 760 + 352 Hz/ –176 Hz 535 + 108 Hz/ – 54 Hz for
for test signal 1 test signal 1
2 400 ± 240 Hz for test 1 200 ± 120 Hz for test
signal 2 signal 2
Transmitter output power versus time Power within mask Not applicable
shown in Figure 11 and
timings given in Table 12
Intermodulation attenuation Not applicable
≥ 40 dB
5.4 Minimum requirements for the TDMA receivers of the AIS Base Station
The minimum technical characteristics as specified in Table 6 shall apply to the TDMA receiv-
ers.
Table 6 – Minimum TDMA receiver characteristics
Receiver parameters 25 kHz channels 12,5 kHz channels
Sensitivity 20 % PER at –107 dBm 20 % PER at –98 dBm
Co-channel rejection 20 % PER at –10 dB 20 % PER at –18 dB
Adjacent channel selectivity 20 % PER at 70 dB 20 % PER at 50 dB
Spurious response rejection 20 % PER at 70 dB Not applicable
Intermodulation response rejection 20 % PER at 74 dB Not applicable
Blocking 20 % PER at 86 dB Not applicable
5.5 Shutdown procedure for an AIS Base Station
An automatic transmitter hardware shutdown procedure and indication shall be provided in
case a transmitter continues its transmission at the end of its transmission period. This fea-
ture shall be independent of the Base Station software control. The AIS Base Station shall
shut down the TDMA transmitter in less than 2 s.
6 Requirements for AIS Base Station
6.1 General
This clause describes the requirements for a Base Station operating as a dependent or inde-
pendent station.
The Base Station may be operated as an independent station that contains all of the function-
ality or as a dependent station that relies on external functionality. It is the responsibility of
the competent authority to ensure proper operation.
When operated as a dependent Base Station, the unit operates under full control of the PSS.
– 16 – 62320-1 © IEC:2007(E)
When operated as an independent Base Station, the unit may be delegated certain autono-
mous functionality under the supervisory control of the PSS.
6.2 Dependent Base Station requirements
This clause describes the functional requirements of an AIS Base Station operating as a de-
pendent unit with regard to internal processing of AIS VDL messages and Presentation Inter-
face sentences.
6.2.1 General rules
When operating as a dependent Base Station, the unit shall comply with the following general
rules:
• each dependent AIS Base Station shall, as a default, be identified by its own individual
MMSI on the VDL interface and the unique identifier on the PI interface. The AIS Base
Station MMSI and unique identifier shall be configurable by means of a SID sentence via
the PI;
• the dependent AIS Base Station shall be capable of transmitting messages with a different
MMSI provided by the PSS by means of a standard VDM input sentence;
• the dependent AIS Base Station shall be able to receive all VDL messages;
• every received VDL message shall be passed to the PI as a VDM sentence without further
data content processing;
• every received PI VDM sentence shall be transmitted on the VDL channel and beginning
in the slot indicated by the linked TSA sentence without further data content processing;
• every message transmitted on the VDL shall be passed to the PI as a VDO sentence
linked with a VSI sentence;
• messages to be transmitted on the VDL are passed using the sentence linking method
(see Annex A);
• the dependent AIS Base Station does not transmit Message 4 without PSS control;
• all transmissions are done via TSA+VDM PI input sentences;
• the dependent AIS Base Station shall not be semaphore qualified and shall not operate
autonomously;
• when the UTC sync source is unavailable, the AIS Base Station shall use UTC indirect or
synchronised to another Base Station;
• upon request via the sentence VER, the dependent AIS Base Station shall provide its
hardware and software version information.
6.2.2 General processing diagram
The AIS Base Station shall internally process data in accordance with Figure 3.
62320-1 © IEC:2007(E) – 17 –
Base Station PI
RX
process output
Message
VDL
Base Station PI
processing and
message
input
configuration
maintenance
TX
process
IEC 152/07
Figure 3 – General processing diagram
6.2.3 AIS Base Station response to PI input
The AIS Base Station shall respond to input sentences from the PI in accordance with
Table 1, “output dependent” when operating as a dependent Base Station.
6.2.4 AIS Base Station response to VDL input
The AIS Base Station shall respond to input messages from the VDL in accordance with Table 7.
Table 7 – Base Station response to input messages from the VDL
VDL input Resulting PI output Resulting VDL output Resulting VDL reporting
rate
Any message (regardless of VDM, VSI Nil Nil
MMSI)
All messages in a frame (re-FSR Nil Nil
gardless of MMSI)
6.3 Independent Base Station requirements
This clause describes the functional requirements of an AIS Base Station operating as an in-
dependent unit with regard to internal processing of AIS VDL messages and Presentation In-
terface sentences.
NOTE Requirements for Base Stations operating as an independent unit are in addition to the requirements for
Base Stations operating as a dependent unit.
6.3.1 General rules
When operating as an independent Base Station, the unit shall comply with the following gen-
eral rules:
• with regard to the access schemes to the VDL, refer to 6.3.4 AIS Base Station interaction
on the VDL;
– 18 – 62320-1 © IEC:2007(E)
• the independent AIS Base Station shall, as a default, use a surveyed position. When using
a surveyed position, the “position accuracy” flag in VDL Message 4 shall be set upon con-
figuration, and the “RAIM” flag shall be set to 0;
• when the UTC sync source is unavailable, the independent AIS Base Station shall use
UTC indirect or the semaphore rules;
• the independent AIS Base Station shall revert to semaphore behaviour upon detection of
semaphore condition on the VDL.
NOTE In order to behave as a semaphore, the independent AIS Base Station must be transmitting Message 4.
The required increase of the reporting rate is autonomous. This behaviour is not influenced by FATDMA or RAT-
DMA.
6.3.2 General processing diagram
The AIS Base Station shall internally process data in accordance with Figure 4.
RX Base Station
PI output
process
Message
VDL
Base Station
processing and
message
PI input
configuration
maintenance
TX
process
IEC 153/07
Figure 4 – General processing diagram
6.3.3 AIS Base Station response to PI input
The AIS Base Station shall respond to input sentences from the PI in accordance with
Table 1 , “output independent” when operating as an independent Base Station.
6.3.3.1 Requirements for configuration of FATDMA access scheme
(Link Management Message)
Use of FATDMA is reserved for Base Stations operating as either dependent or independent.
6.3.3.1.1 Slot reuse
A Base Station’s transmission slots are protected by reservation of slots (Message 4 and 20)
and the 120 nautical mile rule. Slots allocated or reserved by other Base Stations should not
be used for RATDMA unless the other Base Station is located over 120 nautical miles from
the Base Station.
62320-1 © IEC:2007(E) – 19 –
6.3.3.1.2 Configuration of Data Link Management Messages
The Data Link Management Message (Message 20) is a continuously scheduled and transmit-
ted message. The Data Link Management Message applies only to the frequency channel on
which it is transmitted.
The Data Link Management Message shall be used by Base Station(s) to pre-announce the
fixed allocation schedule (FATDMA) for one or more Base Station(s) and it shall be repeated
as often as required.
The AIS Base Station shall use the ECB sentence to schedule the autonomously and continu-
ously transmission of Data Link Management Messages, which refresh the FATDMA reserva-
tions.
6.3.4 AIS Base Station interaction on the VDL
The interaction of the AIS Base Station on the VDL is presented in Table 8.
Table 8 – Base Station response to input messages from the VDL
...
IEC 62320-1
Edition 1.1 2009-05
INTERNATIONAL
STANDARD
Maritime navigation and radiocommunication equipment and systems –
Automatic identification system (AIS) –
Part 1: AIS Base Stations – Minimum operational and performance requirements,
methods of testing and required test results
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IEC 62320-1
Edition 1.1 2009-05
INTERNATIONAL
STANDARD
Maritime navigation and radiocommunication equipment and systems –
Automatic identification system (AIS) –
Part 1: AIS Base Stations – Minimum operational and performance
requirements, methods of testing and required test results
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
CS
ICS 47.020.70 ISBN 978-2-88910-671-4
– 2 – 62320-1 © IEC:2007+A1:2008(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Symbols and abbreviations.8
4 Functional layout of an AIS Base Station .8
4.1 General .8
4.2 Functional block diagram of an AIS Base Station.9
4.3 General VDL requirements .10
4.4 Functional diagram for operation of a Base Station .11
4.5 Base Station input/output sentence formatters.11
5 Functional definition of the radio interface of the AIS Base Station .13
5.1 General requirements of the physical layer.13
5.2 Required parameter settings for the physical layer of the AIS Base Station .13
5.3 Minimum requirements for the TDMA transmitter of the AIS Base Station.14
5.4 Minimum requirements for the TDMA receivers of the AIS Base Station .15
5.5 Shutdown procedure for an AIS Base Station .15
6 Requirements for AIS Base Station.15
6.1 General .15
6.2 Dependent Base Station requirements.16
6.3 Independent Base Station requirements .17
6.4 BIIT conditions .22
6.5 Further requirements for optional features.23
7 Functional definition of the presentation interface of the AIS Base Station.24
7.1 Physical requirements for the presentation interface .24
7.2 Presentation interface data exchange.24
8 Tests of AIS Base Stations – method of measurement and required results.24
8.1 Test conditions.24
9 Physical radio tests .28
9.1 Transceiver protection test .28
9.2 TDMA transmitter .28
9.3 TDMA receivers.36
9.4 Conducted spurious emissions at the antenna.45
10 Functional tests for Base Station .45
10.1 Pre-set-up .46
10.2 Normal operation.47
10.3 Intentional slot reuse (link congestion) .74
10.4 Comment Block Encapsulation .75
Annex A (normative) Additional AIS Base Station sentences .77
of an AIS Base Station .9
Figure 1 – Functional block diagram
Figure 2 – Functional block diagram dependent and independent operation.11
Figure 3 – General processing diagram .17
Figure 4 – General processing diagram .18
62320-1 © IEC:2007+A1:2008(E) – 3 –
Figure 5 – Flow diagram for AIS Base Station response to VDM input.21
Figure 6 – Format for repeating four-packet cluster.25
Figure 7 – Measurement arrangement .29
Figure 8 – Measurement arrangement .30
Figure 9 – Modulation spectrum for slotted transmission 25 kHz .30
Figure 10 – Modulation spectrum for slotted transmission at optional 12,5 kHz .31
Figure 11 – Measurement arrangement for modulation accuracy.32
Figure 12 – Power versus time mask .34
Figure 13 – Measurement arrangement.35
Figure 14 – Measurement arrangement.36
Figure 15 – Measurement arrangement.37
Figure 16 – Measurement arrangement.38
Figure 17 – Measurement arrangement.39
Figure 18 – PER/BER or SINAD measuring equipment .41
Figure 19 – Measurement arrangement for inter-modulation .43
Figure 20 – Measurement arrangement for blocking or de-sensitisation .44
Table 1 – Base Station input/output sentence formatters .12
Table 2 – Required parameter settings for an AIS Base Station .14
Table 3 – Required settings of physical layer constants .14
Table 4 – Bandwidth related parameters of the physical layer of the AIS Base Station.14
Table 5 – Minimum required TDMA transmitter characteristics .15
Table 6 – Minimum TDMA receiver characteristics .15
Table 7 – Base Station response to input messages from the VDL.17
Table 8 – Base Station response to input messages from the VDL.19
Table 9 – BIIT alarm conditions monitored by an AIS Base Station .23
Table 10 – Content of first two packets .26
Table 11 – Fixed PRS data derived from ITU-T O.153 .26
Table 12 – Maximum values of absolute measurement uncertainties.27
Table 13 – Definition of timings for Figure 12.34
Table 14 – Frequencies for inter-modulation tests.43
– 4 – 62320-1 © IEC:2007+A1:2008(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
MARITIME NAVIGATION AND RADIOCOMMUNICATION
EQUIPMENT AND SYSTEMS –
AUTOMATIC IDENTIFICATION SYSTEM (AIS) –
Part 1: AIS Base Stations –
Minimum operational and performance requirements,
methods of testing and required test results
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote interna-
tional co-operation on all questions concerning standardization in the electrical and electronic fields. To this
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Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject
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ganization for Standardization (ISO) in accordance with conditions determined by agreement between the two
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equip-
ment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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penses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publica-
tions.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
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 62320-1 has been prepared by IEC Technical Committee 80: Mari-
time navigation and radiocommunication equipment and systems.
This consolidated version of IEC 62320-1 consists of the first edition (2007) [documents
80/460/FDIS and 80/468/RVD] and its amendment 1 (2008) [documents 80/522/CDV and
80/543/RVC].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 1.1.
A vertical line in the margin shows where the base publication has been modified by amend-
ment 1.
62320-1 © IEC:2007+A1:2008(E) – 5 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 62320 series, under the general title: Maritime navigation and radio-
communication equipment and systems – Automatic Identification System (AIS) can be found
on the IEC website.
The committee has decided that the contents of the base publication and its amendments 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.
– 6 – 62320-1 © IEC:2007+A1:2008(E)
INTRODUCTION
Chapter V of the International Convention for the Safety of Life at Sea 1974 (SOLAS) requires
mandatory carriage of Automatic Identification System (AIS) equipment on all vessels con-
structed on or after 01 July 2002. Carriage for other types and sizes of SOLAS Convention
vessels was required to be completed not later than 31 December 2004.
SOLAS Chapter V, Regulation 19, clause 2.4.5 states that AIS shall:
1 provide automatically to appropriate equipped shore stations, other ships and aircraft in-
formation, including ship's identity, type, position, course, speed, navigational status and
other safety-related information;
2 receive automatically such information from similarly fitted ships;
3 monitor and track ships; and
4 exchange data with shore-based facilities.
In addition, the IMO performance standards for AIS state that:
– The AIS should improve the safety of navigation by assisting in the efficient navigation of
ships, protection of the environment, and operation of Vessel Traffic Services (VTS), by
satisfying the following functional requirements:
1 in a ship-to-ship mode for collision avoidance;
2 as a means for littoral States to obtain information about a ship and its cargo; and
3 as a VTS tool, i.e. ship-to-shore (traffic management).
– The AIS should be capable of providing to ships and to competent authorities, information
from the ship, automatically and with the required accuracy and frequency, to facilitate ac-
curate tracking. Transmission of the data should be with the minimum involvement of
ship's personnel and with a high level of availability.
The provision of Shore Based AIS will be necessary to attain the full benefit of the SOLAS
Convention requirements.
This part of IEC 62320 provides the minimum operational and performance requirements,
methods of test and the required test results for AIS Base Stations. The testing is divided into
three sections, the transceiver tests, the logical tests and the Presentation Interface tests.
These are captured in Clauses 8, 9 and 10 respectively. The method used for testing is that
the EUT should meet all the tests requirements of Clause 8 before proceeding to Clause 9.
Likewise, the unit should meet all of the test requirements before proceeding to Clause 10.
Clause 10 has also been prioritised so that the tests are progressive
Clauses 5 to 7 provide functional requirement information and Clause 8 provides the general
test environment for the EUT.
62320-1 © IEC:2007+A1:2008(E) – 7 –
MARITIME NAVIGATION AND RADIOCOMMUNICATION
EQUIPMENT AND SYSTEMS –
AUTOMATIC IDENTIFICATION SYSTEM (AIS) –
Part 1: AIS Base Stations –
Minimum operational and performance requirements,
methods of testing and required test results
1 Scope
This part of IEC 62320 specifies the minimum operational and performance requirements,
methods of testing and required test results for AIS Base Stations, compatible with the per-
formance standards adopted by IMO Res. MSC.74 (69), Annex 3, Universal AIS. It incorpo-
rates the technical characteristics of non-shipborne, fixed station AIS equipment, included in
recommendation ITU-R M.1371 and IALA Recommendation A-124. Where applicable, it also
takes into account the ITU Radio Regulations. This standard takes into account other associ-
ated IEC international standards and existing national standards, as applicable.
This standard is applicable for AIS Base Stations. It does not include specifications for the
display of AIS data on shore.
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 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 61162-1, Maritime navigation and radiocommunication equipment and systems – Digital
interfaces – Part 1: Single talker and multiple listeners
ITU-R 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 M.1371, Technical characteristics for an automatic identification system using time di-
vision multiple access in the VHF maritime mobile band
ITU-T O.153, Basic parameters for the measurement of error performance at bit rates below
the primary rate
IALA Recommendation A-124 on Automatic Identification System (AIS). Shore Station and
networking aspects relating to the AIS Service
IALA technical clarifications to ITU Recommendation ITU-R M.1371-1
RTCM SC104 – RTCM Recommended Standards for Differential GNSS (Global Navigation
Satellite Systems) Service
– 8 – 62320-1 © IEC:2007+A1:2008(E)
3 Symbols and abbreviations
AIS Automatic Identification System
BER Bit Error Rate
BIIT Built-In Integrity Tests
BT Bandwidth Time product
CPU Central Processing Unit
DGNSS Differential Global Navigation Satellite System
EPFS Electronic position fixing system
EUT Equipment under test
FATDMA Fixed Access Time Division Multiple Access
GNSS Global Navigation Satellite System
IALA International Association of Marine Aids to Navigation and Lighthouse Authorities
IHO International Hydrographic Office
IMO International Maritime Organization
ITU International Telecommunications Union
kn Knots
MAC Medium Access Control
MKD Minimum Keyboard and Display
MMSI Maritime Mobile Service Identity
NM Nautical Mile
NRZI Non-Return to Zero Inverted
PER Packet Error Rate
P Carrier Power
c
PI Presentation Interface
PPS Pulse Per Second
PSS Physical Shore Station
RAIM Receiver Autonomous Integrity Monitoring
RATDMA Random Access Time Division Multiple Access
Rx Receive
TDMA Time Division Multiple Access
Tx Transmit
UTC Universal Time Co-ordinated
VDL VHF Data Link
VSWR Voltage Standing Wave Ratio
VTS Vessel Traffic Services
NOTE Abbreviations related to IEC 61162-1 are not included in the above list. For their meaning refer to that
standard and Annex A.
4 Functional layout of an AIS Base Station
4.1 General
The Base Station may be designed for dependent only operation or independent operation.
Both are under some control of the Physical Shore Station (PSS) as defined in the IALA Rec-
ommendation A-124.
62320-1 © IEC:2007+A1:2008(E) – 9 –
– A dependent Base Station accesses the VHF data link (VDL) using only the combination of
linked TSA+VDM sentences (see Table 1), as provided by the PSS.
– An independent Base Station accesses the VDL using either the combination of linked
TSA+VDM sentences as provided by the PSS or by using internal control. When operated
as an independent Base Station the unit may be delegated certain autonomous functional-
ity under the supervisory control of the PSS.
The PSS, or external controlling entity, is responsible for Base Station configuration, trans-
mission scheduling, and processing of received information. Presentation Interface (PI) text
sentences are used to configure the Base Station, schedule message transmissions, and out-
put information.
When TSA and VDM sentences are used, the PSS is responsible for ensuring the integrity of
the VDL.
The tests in this standard are for all Base Stations. Additional tests for independent Base Sta-
tions are indicated by a note located at the beginning of each appropriate test section.
4.2 Functional block diagram of an AIS Base Station
Figure 1 shows the principal components of the AIS Base Station.
AIS Base Station
AIS TX
I/O
Controller
Options
Internal
Ext UTC
synchronisation
sync
source
DGNSS
AIS RX
RTCM SC104
BIIT
AIS RX
Power supply
IEC 150/07
Figure 1 – Functional block diagram of an AIS Base Station
As a minimum, the following functional elements are required for the AIS Base Station:
• two multi-channel receivers;
• one multi-channel TDMA transmitter;
NOTE Since the minimum configuration of the AIS Base Station has only one transmitter, the AIS Base Sta-
tion cannot transmit on both AIS Channels (AIS A and AIS B) simultaneously.
• a controlling unit;
• an internal synchronisation source, which may also be used as a position sensor for inde-
pendent Base Stations. If used as a position source, the internal GNSS receiver shall
meet the appropriate requirements of IEC 61108-1;
• a Built-In-Integrity-Test unit (BIIT), which shall provide alarms;
Presentation interface
– 10 – 62320-1 © IEC:2007+A1:2008(E)
• a power supply;
• a Presentation Interface (PI), which allows the AIS Base Station to exchange sentences
with the PSS;
• optional features, for example: DGNSS (RTCM SC104); external synchronisation; DSC
functionality.
4.3 General VDL requirements
The AIS Base Station interacts with the VDL by receiving and transmitting VDL messages.
4.3.1 Sources of VDL messages for transmission
In order to transmit VDL messages, the Base Station may derive the messages to be transmit-
ted from three sources:
a) generate and transmit VDL messages autonomously as per the configuration received via
sentences;
b) generate and transmit VDL messages automatically based on data input received via the
PI, using different sentences from that of the VDM;
c) transmit predefined VDL messages input via the PI. The VDM sentence shall be used to
input the content of the VDL messages via the PI to the AIS Base Station. The VDL mes-
sage shall then be transmitted by the Base Station on the VDL.
When operating the Base Station independently, these three VDL message sources shall be
supported in parallel.
When operating the Base Station dependently, only VDM messages received via the PI shall
be transmitted as noted in item c) above.
4.3.2 Use of access schemes
4.3.2.1 Dependent operation
When operating as a dependent Base Station the FATDMA access scheme shall be used. The
Base Station shall use the slot(s) provided by the combination of linked TSA+VDM sentences.
The TSA sentence provides the channel and start slot information. The actual number of slots
used is based on the number of bits conveyed by the VDM sentence(s).
Dependent operation shall not use the RATDMA access scheme
4.3.2.2 Independent operation
The default access scheme for a Base Station shall be FATDMA.
The AIS Base Station may also use RATDMA access schemes if implemented. The AIS Base
Station may use the FATDMA and RATDMA access schemes concurrently. The use of pre-
reserved FATDMA slots shall take priority over RATDMA access.
When using the FATDMA access scheme, the absolute slot numbers for transmission shall be
determined by one of the following methods:
• the PI combination of linked TSA+VDM sentences shall provide the absolute slot number
in which the AIS Base Station transmits;
• the AIS Base Station shall autonomously select an appropriate pre-reserved FATDMA slot
as determined by its configuration.
Both methods shall be available and operate concurrently.
62320-1 © IEC:2007+A1:2008(E) – 11 –
4.4 Functional diagram for operation of a Base Station
Figure 2 shows the principal components of an AIS Base Station. The diagram identifies the
elements of the AIS Base Station and the PI with the PSS.
Physical
External message
Shore
processing and generation
TSA+VDM
Station
Presentation Interface I/O
DGNSS
ALR PI-input
ABK
(RTCM)
TXT and Table 1
queries
Autonomous message
Base Base Station configuration
processing and generation
and management
Station
VDO
TFR
VSI
UTC
sync VDL
mesage
source
Time (slot)
VDL SYNC
TIME
queue
reference
information UTC
control
process
indirect and
VDM
semaphore
FSR
VSI
Slot timing reference
Rx process Tx process
VDL
message
IEC 151/07
Figure 2 – Functional block diagram dependent and independent operation
The PI of an AIS Base Station consists of at least one input/output port. A specific choice for
the physical input/output port is not specified. The purpose of the PI is to:
• exchange VDL messages with the PSS;
• configure the Base Station;
• enable real time control of the Base Station;
• provide an output for BIIT alarms and status.
The information exchange of the PI is supported by a combination of IEC 61162-1 sentences
and Base Station sentences (see Annex A).
4.5 Base Station input/output sentence formatters
The following table lists sentence formatters used with a Base Station. It includes existing
sentence formatters (grey rows) and sentence formatters developed for use with Base Sta-
tions (white rows). Clause A.1 contains the details for each of the sentence formats developed
for AIS Base Stations.
A sentence linking method is described in Annex A.2. Use of this method improves the integ-
rity of data relationships between sentences, and improves the reliability and clarity of com-
munications with the Base Station.
– 12 – 62320-1 © IEC:2007+A1:2008(E)
Table 1 presents presents both input and output sentence formatters for dependent and inde-
pendent operation. For Base Stations that support both independent and dependent opera-
tion, both sets of sentences are applicable. For Base Stations that only support dependent
operation, the sentences for dependent operation are applicable and all other sentences are
ignored.
Table 1 – Base Station input/output sentence formatters
Sentence Input Input Output Output
Description
formatter independent dependent independent dependent
Addressed and binary broadcast
ABK X
acknowledgement
Addressed binary and safety re-
ABM X
lated message
AIS regional channel assignment
ACA X Q
message
Preparation and initiation of an
AIS Base Station addressed
ACM X
channel message (VDL Message
22)
ACK X X Acknowledge alarm
AIS Device Status (output interval
ADS X X configured by BCE and upon
status change)
Preparation and initiation of an
AIS Base Station broadcast of a
AGA X Q
group assignment message
(Message 23)
ALR X X Set alarm state
AIS interrogation request (VDL
AIR X
Message 15)
Preparation and initiation of an
ASN X AIS Base Station broadcast of
assignment VDL Message 16
BBM X Broadcast binary message
General Base Station
BCE X X Q Q
configuration extended
General Base Station
BCF X X Q Q
configuration
CAB X X Q Q
Control AIS Base Station
Not supported by this IEC
CBM
standard
Data Link Management slot
allocations for Base Station (VDL
DLM X Q
Message 20 – FATDMA
reservations)
Configure broadcast rates for
ECB X Q
Base Station messages with
epoch planning support
Frame summary of AIS reception,
defined by SPO. The manufacturer
FSR X X
shall declare the parameters that
are supported
Installation of a station’s
SID X X
identification
Select AIS device’s reception
SPO X X Q Q
processing and output
62320-1 © IEC:2007+A1:2008(E) – 13 –
TFR Transmit feed-back report – Base
Station report on status of
X X
requested transmission. Automatic
status response of TSA+VDM
Transmit Slot Assignment – used
to identify AIS time slot used to
TSA X X
transmit the content of a VDM
sentence. TSA shall preceed the
VDM sentence
TSP X Transmit Slot Prohibit
Transmit Slot Prohibit status
TSR X
Report. Automatic status response
of TSP
VDM X X X X VHF Data-link message
VHF Data-link Own-vessel mes-
VDO X X
sage
Version information about equip-
VER Q Q ment. Provided in response to
ABQ
VDL Signal Information, defined
by SPO. The manufacturer shall
declare the parameters that are
VSI X X
supported and the corresponding
accuracy. The VSI shall follow its
associated VDM/VDO
NOTE 1 “X” indicates input to, or output from, the AIS Base Station. “Q” indicates that the sentence may be ex-
ternally requested using the IEC 61162-1 “$xxABQ,xxx” query sentence (see Annex A) method(s) in order for the
identified sentence to be output.
NOTE 2 Sentence formatters shown in shaded rows are described in IEC 61162-1.
The AIS Base Station shall output, autonomously and periodically, the ADS sentence on the
PI indicating the Base Station status. This shall be output once per minute or when there is a
change in the status.
5 Functional definition of the radio interface of the AIS Base Station
The physical layer of the AIS Base Station shall be designed in accordance with the following
minimum requirements.
5.1 General requirements of the physical layer
The following general requirements apply to all receivers and transmitter:
• a Base Station shall use simplex channels or duplex channels in either full-duplex or half-
duplex mode;
• a Base Station shall be capable of 25 kHz and, optionally, 12,5 kHz emission/reception in
accordance with ITU-R M.1084-4, Annex 3 (as referenced by Recommendation ITU-R
M.1371);
• a Base Station shall be capable of transmitting using at least two different power settings,
as provided for by ITU-R M.1371 and IALA technical clarifications to ITU-R M.1371. The
Base Station shall have the capability to set its power level as stipulated by an input com-
mand.
5.2 Required parameter settings for the physical layer of the AIS Base Station
Table 2, Table 3 and Table 4 are derived from Recommendation ITU-R M.1371 and give the
parameters required for an AIS Base Station.
– 14 – 62320-1 © IEC:2007+A1:2008(E)
NOTE For the meaning of the symbols and additional information refer to the appropriate clause of Recommenda-
tion ITU-R M.1371.
The constants of the physical layer of the AIS Base Station shall comply with the values given
in Table 3 and Table 4.
Table 2 – Required parameter settings for an AIS Base Station
Symbol Parameter name Low setting High setting
PH.RFR Regional frequencies 156,025 MHz 162,025 MHz
PH.CHS Channel spacing 12,5 kHz Optional 25 kHz
PH.AIS1 AIS 1 (default channel 1) 161,975 MHz 161,975 MHz
PH.AIS2 AIS 2 (default channel 2) 162,025 MHz 162,025 MHz
PH.CHB Channel bandwidth 12,5 kHz 25 kHz
Narrow Optional Wide
PH.BR Bit rate 9 600 bps 9 600 bps
PH.TS Training sequence Always start with a zero 24 bits 24 bits
(0101010…)
PH.TST Transmitter settling time (Transmit power within 20 %
≤ 1,0 ms ≤ 1,0 ms
of final value, frequency stable to within ± 1,0 kHz of
final value)
Table 3 – Required settings of physical layer constants
Symbol Parameter name Value
PH.DE Data encoding NRZI
PH.FEC Forward error correction Not used
PH.IL Interleaving Not used
PH.BS Bit scrambling Not used
PH.MOD Modulation Bandwidth adapted; GMSK (see Table 4)
Table 4 – Bandwidth related parameters of the physical layer of the AIS Base Station
Symbol Parameter name PH.CHB/narrow PH.CHB/wide
PH.TXBT Transmit BT-product 0,3 0,4
PH.RXBT Receive BT-product 0,3 0,5
PH.MI Modulation index 0,25 0,50
5.3 Minimum requirements for the TDMA transmitter of the AIS Base Station
The minimum technical characteristics as specified in Table 5 shall apply to the TDMA trans-
mitters.
62320-1 © IEC:2007+A1:2008(E) – 15 –
Table 5 – Minimum required TDMA transmitter characteristics
Transmitter parameters 25 kHz channels 12,5 kHz channels
Carrier power error
± 1,5 dB ± 1,5 dB
Carrier frequency error ± 500 Hz ± 500 Hz
Spectrum mask for slotted transmissions
–25 dBc at ± 10 kHz 0 dBc at ± 2,5 kHz
–70 dBc at ± 25 kHz –60 dBc at ± 12,5 kHz
Transmitter test sequence and modulation accuracy ‘0’ bit start for test signals 1 ‘0’ bit start for test sig-
and 2 nals 1 and 2
1 760 Hz + 352 Hz/ –176 Hz 535 Hz + 108 Hz/ –54 Hz
for test signal 1 for test signal 1
2 400 Hz ± 240 Hz for test 1 200 Hz ± 120 Hz for
signal 2 test signal 2
Transmitter output power versus time Power within mask shown in Not applicable
Figure 11 and timings given
in Table 12
Intermodulation attenuation Not applicable
≥ 40 dB
5.4 Minimum requirements for the TDMA receivers of the AIS Base Station
The minimum technical characteristics as specified in Table 6 shall apply to the TDMA receiv-
ers.
Table 6 – Minimum TDMA receiver characteristics
Receiver parameters 25 kHz channels 12,5 kHz channels
Sensitivity 20 % PER at –107 dBm 20 % PER at –98 dBm
Co-channel rejection 20 % PER at –10 dB 20 % PER at –18 dB
Adjacent channel selectivity 20 % PER at 70 dB 20 % PER at 50 dB
Spurious response rejection 20 % PER at 70 dB Not applicable
Intermodulation response rejection 20 % PER at 74 dB Not applicable
Blocking 20 % PER at 86 dB Not applicable
5.5 Shutdown procedure for an AIS Base Station
An automatic transmitter hardware shutdown procedure and indication shall be provided in
case a transmitter continues its transmission at the end of its transmission period. This fea-
ture shall be independent of the Base Station software control. The AIS Base Station shall
shut down the TDMA transmitter in less than 2 s.
6 Requirements for AIS Base Station
6.1 General
This clause describes the requirements for a Base Station operating as a dependent or inde-
pendent station.
The Base Station may be operated as an independent station that contains all of the function-
ality or as a dependent station that relies on external functionality. It is the responsibility of
the competent authority to ensure proper operation.
– 16 – 62320-1 © IEC:2007+A1:2008(E)
When operated as a dependent Base Station, the unit operates under full control of the PSS.
When operated as an independent Base Station, the unit may be delegated certain autono-
mous functionality under the supervisory control of the PSS.
6.2 Dependent Base Station requirements
This clause describes the functional requirements of an AIS Base Station operating as a de-
pendent unit with regard to internal processing of AIS VDL messages and Presentation Inter-
face sentences.
6.2.1 General rules
When operating as a dependent Base Station, the unit shall comply with the following general
rules:
• each dependent AIS Base Station shall, as a default, be identified by its own individual
MMSI on the VDL interface and the unique identifier on the PI interface. The AIS Base
Station MMSI and unique identifier shall be configurable by means of a SID sentence via
the PI;
• the dependent AIS Base Station shall be capable of transmitting messages with a different
MMSI provided by the PSS by means of a standard VDM input sentence;
• the dependent AIS Base Station shall be able to receive all VDL messages;
• every received VDL message shall be passed to the PI as a VDM sentence without further
data content processing;
• every received PI VDM sentence shall be transmitted on the VDL channel and beginning
in the slot indicated by the linked TSA sentence without further data content processing;
• every message transmitted on the VDL shall be passed to the PI as a VDO sentence
linked with a VSI sentence;
• messages to be transmitted on the VDL are passed using the sentence linking method
(see Annex A);
• the dependent AIS Base Station does not transmit Message 4 without PSS control;
• all transmissions are done via TSA+VDM PI input sentences;
• the dependent AIS Base Station shall not be semaphore qualified and shall not operate
autonomously;
• when the UTC sync source is unavailable, the AIS Base Station shall use UTC indirect or
shall be synchronised to another Base Station;
• upon request via the sentence VER, the dependent AIS Base Station shall provide its
hardware and software version information.
62320-1 © IEC:2007+A1:2008(E) – 17 –
6.2.2 General processing diagram
The AIS Base Station shall internally process data in accordance with Figure 3.
Base Station PI
RX
process output
Message
VDL
Base Station PI
processing and
message
input
configuration
maintenance
TX
process
IEC 152/07
Figure 3 – General processing diagram
6.2.3 AIS Base Station response to PI input
The AIS Base Station shall respond to input sentences from the PI in accordance with
Table 1, “output dependent” when operating as a dependent Base Station.
6.2.4 AIS Base Station response to VDL input
The AIS Base Station shall respond to input messages from the VDL in accordance with Table 7.
Table 7 – Base Station response to input messages from the VDL
VDL input Resulting PI output Resulting VDL output Resulting VDL reporting
rate
Any message (regardless of VDM, VSI Nil Nil
MMSI)
All messages in a frame (re-FSR Nil Nil
gardless of MMSI)
6.3 Independent Base Station requirements
This clause describes the functional requirements of an AIS Base Station operating as an in-
dependent unit with regard to internal processing of AIS VDL messages and Presentation In-
terface sentences.
NOTE Requirements for Base Stations operating as an independent unit are in addition to the requirements for
Base Stations operating as a dependent unit.
– 18 – 62320-1 © IEC:2007+A1:2008(E)
6.3.1 General rules
When operating as an independent Base Station, the unit shall comply with the following gen-
eral rules:
• with regard to the access schemes to the VDL, refer to 6.3.4 AIS Base Station interaction
on the VDL;
• the independent AIS Base Station shall, as a default, use a surveyed position. When using
a surveyed position, the “position accuracy” flag in VDL Message 4 shall be set upon con-
figuration, and the “RAIM” flag shall be set to 0;
• when the UTC sync source is unavailable, the independent AIS Base Station shall use
UTC indirect or the semaphore rules as defined by ITU-R M.1371;
• the independent AIS Base Station shall revert to semaphore behaviour upon detection of
semaphore condition on the VDL;
• all VDL messages shall be as short as possible.
NOTE In order to behave as a semaphore, the independent AIS Base Station must be transmitting Message 4.
The required increase of the reporting rate is autonomous. This behaviour is not influenced by FATDMA or RAT-
DMA.
6.3.2 General processing diagram
The AIS Base Station shall internally process data in accordance with Figure 4.
Base Station
RX
process PI output
Message
VDL
Base Station
processing and
message
PI input
configuration
maintenance
TX
process
IEC 153/07
Figure 4 – General processing diagram
6.3.3 AIS Base Station response to PI input
The AIS Base Station shall respond to input sentences from the PI in accordance with
Table 1 , “output independent” when operating as an independent Base Station.
6.3.3.1 Requirements for configuration of FATDMA access scheme
(Link Management Message)
Use of FATDMA is reserved for Base Stations operating as either dependent or independent.
62320-1 © IEC:2007+A1:2008(E) – 19 –
6.3.3.1.1 Slot reuse
A Base Station’s transmission slots are protected by reservation of slots (Message 4 and 20)
and the 120 nautical mile rule. Slots allocated or reserved by other Base Stations should not
be used for RATDMA unless the other Base Station is located over 120 nautical miles from
the Base Station.
6.3.3.1.2 Configuration of Data Link Management Messages
The Data Link Management Message (Message 20) is a continuously scheduled and transmit-
ted message. The Data Link Management Message applies only to the frequency channel on
which it is transmitted.
The Data Link Management Message shall be used by Base Station(s) to pre-announce the
fixed allocation schedule (FATDM
...
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