ITU-R M.1371-6 (02/2026)

CONTENTS
Recommendation ITU-R M.1371-6
INTELLECTUAL PROPERTY RIGHTS
Annex 1 Operational characteristics of an automatic identification system using time division multiple access techniques in the VHF maritime mobile frequency band
A1-1 General
A1-2 Automatic identification system equipment
A1-2.1 Automatic identification system VHF data link non-controlling stations
A1-2.1.1 Automatic identification system shipborne station
A1-2.1.2 Automatic identification system Aids to navigation station
A1-2.1.3 Automatic identification system aircraft station in maritime mobile service
A1-2.1.4 Automatic identification system repeater station
A1-2.1.5 Automatic identification system locating devices
A1-2.1.6 AMRD Group B
A1-2.2 Automatic identification system VHF data link controlling stations
A1-2.2.1 Base station
A1-3 Identification
A1-4 Reporting schedule for transmitting information
A1-5 Frequency band
Annex 2 Technical characteristics of an automatic identification system using time division multiple access techniques in the maritime mobile band
A2-1 Structure of the automatic identification system
A2-1.1 Automatic identification system layer module
A2-1.2 Responsibilities of automatic identification system layers for preparing automatic identification system data for transmission
A2-1.2.1 Transport layer
A2-1.2.2 Network layer
A2-1.2.3 Link layer
A2-1.2.4 Physical layer
A2-2 Physical layer
A2-2.1 Parameters
A2-2.1.1 General
A2-2.1.2 Constants
A2-2.1.3 Transmission media
A2-2.1.4 Multi-channel operation
A2-2.2 Transceiver characteristics
A2-2.3 Modulation scheme
A2-2.3.1 Gaussian minimum shift keying
A2-2.3.2 Frequency modulation
A2-2.3.3 Frequency stability
A2-2.4 Data transmission bit rate
A2-2.5 Training sequence
A2-2.6 Data encoding
A2-2.7 Forward error correction
A2-2.8 Interleaving
A2-2.9 Bit scrambling
A2-2.10 Data link sensing
A2-2.11 Transmitter transient response
A2-2.11.1 Switching time
A2-2.12 Transmitter power
A2-2.13 Shutdown procedure
A2-2.14 Safety precautions
A2-3 Link layer
A2-3.1 Sub-layer 1: medium access control
A2-3.1.1 Time division multiple access synchronization
A2-3.1.2 Time division
A2-3.1.3 Slot phase and frame synchronization
A2-3.1.4 Slot identification
A2-3.1.5 Slot access
A2-3.1.6 Slot state
A2-3.2 Sub layer 2: data link service
A2-3.2.1 Data link activation and release
A2-3.2.2 Data transfer
A2-3.2.3 Error detection and control
A2-3.3 Sub layer 3 – link management entity
A2-3.3.1 Access to the data link
A2-3.3.2 Modes of operation
A2-3.3.3 Initialization
A2-3.3.4 Channel access schemes
A2-3.3.5 Autonomous and continuous operation
A2-3.3.6 Assigned operation
A2-3.3.7 Message structure
A2-4 Network layer
A2-4.1 Multi-channel operation
A2-4.1.1 Operating frequency channels
A2-4.1.2 Normal default mode of multi-channel operation
A2-4.1.3 Regional operating areas
A2-4.1.4 Geographical area power control
A2-4.1.5 Resumption of operation after power on
A2-4.1.6 Priority of channel management commands and clearing of stored regional operating settings
A2-4.2 Distribution of transmission packets
A2-4.2.1 The user directory
A2-4.2.2 Routing of transmission packets
A2-4.2.3 Management of priority assignments for messages
A2-4.3 Changing reporting interval
A2-4.3.1 Autonomously changed Rr (continuous and autonomous mode)
A2-4.3.2 Assigned Rr
A2-4.4 Data link congestion resolution
A2-4.4.1 Intentional slot reuse by the own station
A2-4.4.2 Use of assignment for congestion resolution
A2-4.5 Base station operation
A2-4.6 Repeater application
A2-4.6.1 Repeat indicator
A2-4.6.2 Repeater operation
A2-4.7 Handling of errors related to packet sequencing and groups of packets
A2-5 Transport layer
A2-5.1 Definition of transmission packet
A2-5.2 Conversion of data into transmission packets
A2-5.2.1 Conversion to transmission packets
A2-5.3 Transmission packets
A2-5.3.1 Addressed Messages 6 and 12
A2-5.3.2 Broadcast messages
A2-5.3.3 Conversion to presentation interface messages
A2-5.4 Presentation interface protocol
Annex 3 Long-range applications
A3-1 General
A3-2 Long-range applications by broadcast
A3-2.1 Packet bit structure for the automatic identification system satellite uplink
A3-2.2 Automatic identification system satellite message
A3-2.3 Transmission method for automatic identification system satellite message
A3-2.3.1 Transmission interval
A3-2.3.2 Access scheme
A3-2.3.3 Automatic identification system shore station qualifier
A3-2.3.4 Transmitting the AIS Message 27
Annex 4 Application specific messages
A4-1 General
A4-1.1 Binary messages
A4-1.2 Definition of application identifiers
A4-1.3 Definition of function messages
A4-2 Binary data structure
A4-2.1 Application identifier
A4-2.1.1 Test application identifier
A4-2.1.2 International application identifier
A4-3 Guidelines for creating functional messages
A4-3.1 International functional messages
A4-3.2 Regional functional messages
A4-4 Guidelines for drafting functional messages
A4-5 Definitions of system related international function messages
A4-5.1 International function message 0: Text using 6-bit ASCII
A4-5.2 International function message 2: Interrogation for a specific functional message
A4-5.3 International function message 3: Capability interrogation
A4-5.4 International function message 4: Capability reply
A4-5.5 International function message 5: Application acknowledgement to an addressed binary message
Annex 5 Sequencing of transmission packets
Annex 6 Class B automatic identification system using carrier sense time division multiple access technology
A6-1 Definition
A6-2 General requirements
A6-2.1 General
A6-2.1.1 Capabilities of the Class B “CS” automatic identification system
A6-2.1.2 Modes of operation
A6-3 Performance requirements
A6-3.1 Composition
A6-3.2 Operating frequency channels
A6-3.3 Internal global navigation satellite system receiver for position reporting
A6-3.4 Identification
A6-3.5 Automatic identification system Information
A6-3.5.1 Information content
A6-3.5.2 Information reporting intervals
A6-3.5.3 Transmitter shutdown procedure
A6-3.5.4 Static data input
A6-4 Technical requirements
A6-4.1 General
A6-4.2 Physical layer
A6-4.2.1 Transceiver characteristics
A6-4.2.2 Transmitter requirements
A6-4.2.3 Receiver parameters
A6-4.3 Link layer
A6-4.3.1 Link sub-layer 1: medium access control
A6-4.3.2 Link sub-layer 2: data link service
A6-4.3.3 Link sub-layer 3 – link management entity
A6-4.4 Network layer
A6-4.4.1 Dual channel operation
A6-4.4.2 Channel management
A6-4.4.3 Distribution of transmission packets
A6-4.4.4 Data link congestion resolution
A6-4.5 Transport layer
A6-4.5.1 Transmission packets
A6-4.5.2 Sequencing of data packets
Annex 7 Automatic identification system messages
A7-1 Message types
A7-2 Message summary
A7-3 Message descriptions
A7-3.1 Messages 1, 2, 3: Position reports
A7-3.2 Message 4: Base station report
A7-3.3 Message 5: Ship static and voyage related data
A7-3.3.1 The data terminal equipment indicator
A7-3.3.2 Type of ship
A7-3.3.3 Reference point for reported position and overall dimensions of ship
A7-3.4 Message 6: Addressed binary message
A7-3.5 Message 7: Binary acknowledge
A7-3.6 Message 8: Binary broadcast message
A7-3.7 Message 9: Standard aircraft station in the maritime mobile service position report
A7-3.8 Message 10: Coordinated universal time and date inquiry
A7-3.9 Message 11: Coordinated universal time/date response
A7-3.10 Message 12: Addressed safety related message
A7-3.11 Message 13: Safety related acknowledge
A7-3.12 Message 14: Safety related broadcast message
A7-3.13 Message 15: Interrogation
A7-3.14 Message 16: Assigned mode command
A7-3.15 Message 17: Global navigation-satellite system broadcast binary message
A7-3.16 Message 18: Standard Class B equipment position report
A7-3.17 Message 19: Extended Class B equipment position report
A7-3.18 Message 20: Data link management message
A7-3.19 Message 21: Aids-to-navigation report
A7-3.19.1 Dimension/reference for position of AtoNs
A7-3.20 Message 22: Channel management
A7-3.21 Message 23: Group assignment command
A7-3.22 Message 24: Static data report
A7-3.23 Message 25: Single slot binary message
A7-3.24 Message 26: Multiple slot binary message with communications state
A7-3.25 Message 27: Automatic identification system satellite message
A7-3.26 Message 28: Aid-to-Navigation Report (Single-slot message)
Annex 8 Requirements for stations using burst transmissions
A8-1 Requirements for stations using burst transmissions
A8-2 Transceiver characteristics
A8-3 Transmitter requirements
A8-4 Synchronization accuracy
A8-5 Channel access scheme
A8-6 Supplemental ID information

This Recommendation provides the technical characteristics of an automatic identification system (AIS) using time division multiple access in the very high frequency (VHF) maritime mobile band.