GB/T 47708-2026Performance and test requirements for application specific message (ASM) shipborne equipment (English PDF)

5.7.1 General Requirements

5.7.1.1 talkerID The device should use the talkerID when outputting VDL received data, and only when the device outputs ASM message 0 via PI, and it should conform to... According to the provisions of Table 1.

5.7.1.2 PI Function The device should have a PI (Portable Component) to perform the following functions.

a) Receive messages from other shipboard equipment and transmit them to other ASM stations using this equipment;

b) Output all received broadcast or addressing ASM data sent to this station;

c) Send equipment internal status and configuration information to other shipboard equipment or systems;

d) Accept configuration instructions from other shipboard equipment or systems.

5.7.2 PI Binary Message Datagram

5.7.2.1 Message Header Parameters When communicating via PI, the device should use the binary message datagram format specified in IEC 61162-450.2024.(Compliant) The binary message datagram specified in IEC 61162-450.2024 should begin with a message header, followed by the PI binary message structure. The message header is used for synchronization and data integrity verification as specified in IEC 61162-450.2024. The message header parameters should conform to the specifications in Table 2.

5.7.2.2 Message Header Format Binary message datagrams should use "UdPtD" as a token. The first 6 bytes of a UDP multicast datagram should contain a token, followed by... Followed by one empty character, which conforms to the requirements of Table 3.

5.7.2.3 Binary Message Format The format of the PI binary message shall conform to the specifications in Table

4.The identifier of the PI binary message shall conform to the specifications in Appendix A.

5.7.3 Alarm Information Interface It should comply with the relevant provisions of GB/T 46415-2025.

5.7.4 Equipment Status Table 5 defines the binary message structure used by the device to report its status to other devices on board. The status identifier should conform to Table 6. Regulation.

5.7.5 Equipment Configuration

5.7.5.1 Equipment Configuration Parameters Device configuration inputs or reports should use the "Device Configuration Value" PI binary message structure. After receiving the "Device Configuration Information Request" PI binary message structure, the device should output the corresponding "Device Configuration Value" PI binary message. The structure should be as a response. The binary message structure used for device configuration should conform to the specifications in Table

7.The configuration identifier should conform to the specifications in Table 8.

5.7.5.2 ASM Configuration Parameters In response to an inquiry request, ASM configuration parameters should be stored in the format specified in IMOSN.1/Circ.289. ASM configuration parameters should meet the following requirements.

a) Identifiers that conform to the requirements in Table 8;

b) Sub-identifier, namely the International Application Identifier (IAI) of ASM;

c) Length, conforming to the specifications in Table 9;

d) The data conforms to the requirements of Table 9.

5.7.6 ASM Transmission PI

5.7.6.1 General Rules The device should be able to assemble the received complete MITDMA data packet group and use ASM to receive PI binary message structures via PI output data. Information from incomplete data packet groups should be discarded; that is, partially received information should not be used for ASM reception of PI binary data. The message structure is output via PI. Furthermore, the device can optionally output all received messages applicable to this device via PI binary message structure. The station's ASMVDL radio message functionality.

5.7.6.2 Input Message Interface to ASMVDL The interface data format should conform to the relevant requirements of 5.7.2.Table 10 specifies the data input to the device for transmission to ASM VDL. The PI binary message structure to be used. The specific binary message structure should conform to the provisions of Appendix A.

5.7.6.3 Output the received ASMVDL message interface The interface should conform to IEC 61162-450.2024.Table 11 specifies the statement format, and Table 12 specifies the statements applied to the slave device output. The binary message structure of ASMVDL data. Statements should be transmitted using the IEC 61162-450.2024 message header UdPtD (see...). 5.7.2). The specific binary message structure should conform to the provisions of Appendix A.

5.8 Alarm Management Alarm management shall comply with the provisions of

6.10 in GB/T 46415-2025.

5.9 Physical Layer

5.9.1 General Requirements The physical layer should include the following functions.

a) Define the modulation and demodulation methods for TDMA signal transmission on VDL;

b) Specify the radio frequency technical characteristics of TDMA transmitters and TDMA receivers.

5.9.2 Transmitter

5.9.2.1 Emission Characteristics The technical characteristics of the equipment transmitter should conform to the specifications in Table 13.

5.9.2.2 Transmitter Power and Time Characteristics The transmitter power and timing characteristics of the equipment should meet the requirements of Table 15 and Figure

2.The blue line in Figure 2 represents the transmitter power during ramp-up and ramp-down. Example of the ramp-down process. For multi-slot transmission, the ramp-down and protection phases (from TE through TG to T0) occur in the last transmit time slot. Finally, the synchronization sequence and payload period (TBTE) run through all launch slots.

5.9.3 Receiver The technical characteristics of the equipment receiver should conform to the provisions of Table 16.

5.10 Link Layer

5.10.1 General Requirements The equipment should meet the following requirements.

a) The equipment operates only in autonomous mode, as specified in Annex 3,

4.5.4 of ITU-R M.2092-1.2022;

b) On both ASM channels, the device may use a maximum of 50 time slots per frame for transmission (duty cycle of 2.2%, excluding those used for retransmission). Available time slots for transmitting addressing data (100 time slots in total across 2 channels).

c) The silence period after each MITDMA transmission or a single non-MITDMA transmission;

d) The data packet group transmitted by the device may contain a maximum of 15 MITDMA transmissions;

Note. Acknowledgments for addressing MITDMA are not part of the data packet group.

e) The transmission of MITDMA data packets is completed on the same ASM channel (channel cannot be switched);

f) The device must support receiving at least 10 ongoing MITDMA data packets. If the maximum number of packets to receive is exceeded, priority will be given to processing ongoing packets. In progress MITDMA data packet group;

g) The equipment may transmit in no more than 3 time slots at a time;

h) If a VDL message is broadcast or addressed to this station, use ASM to receive the PI binary message structure and transmit it to the PI;

i) The device transmits messages according to the PI binary message structure of the ASM transmission and ASM geomulticast input to its PI. When the "Format" field of the input statement is empty (the default setting, indicating that the device decides the FEC encoding), no increase in transmission... Given the required number of time slots, the equipment should use FEC.

5.10.2 Access Solution The equipment access scheme shall comply with the relevant provisions of Annex 3, Section

4.5.7 of ITU-R M.2092-1.2022.

5.10.3 Device Interaction on VDL

5.10.3.1 Types and Use of VDL Messages The VDL interaction message types of the device should conform to the specifications in Table 17.

5.10.4 MITDMA Transmission and Retransmission

5.10.4.1 MITDMA Transmission 5.10.4.1.1 MITDMA Access Principle If the transmitted data length requires more than 3 time slots, the data should be divided into data blocks of 3 time slots each, and... MITDMA technology concatenates data packets to form a packet stream. A maximum of 15 MITDMA transmissions can be concatenated. If the data originates from PI... If the data exceeds this limit, a negative response should be returned via PI. 5.10.4.1.2 Initial Launch and Early Time Slot Reservations (Tx1, Tx2) The first transmission (Tx1) of the MITDMA data packet group is always a single time slot and should meet the following requirements.

a) Determine the candidate time slots for Tx1 and apply the RATDMA algorithm until the transmission conditions are met.

b) Before Tx1 is launched, identify up to three candidate time slots for subsequent launches, randomly select a time slot from the candidate list, and calculate the offset. The offset is recorded in the MITDMA communication status, as follows: 1) Time slot increment 1 is reserved; 2) Time slot increment 2 is reserved for Tx3; 3) Time slot increment 3 is used to reserve Tx4.

c) Before sending Tx2, determine the candidate time slot for the next transmission (e.g., Tx5) and select it randomly, then update the communication status. 1) Time slot increment 1 is used to reserve Tx3; 2) Time slot increment 2 is reserved for Tx4; 3) Time slot increment 3 is used to reserve Tx5. 5.10.4.1.3 Later time slot reservation (Txn-2, Txn-1, Txn) For broadcast messages, starting from Txn-2, the unused timeslot increment should be set to 0. Addressing messages should meet the following requirements.

a) In the Txn-2 phase, determine the candidate time slots for the response message, randomly select the response time slot, calculate the offset, and record its communication status. The content is as follows: 1) A time slot increment of 1 is reserved for Txn-1; 2) Time slot increment 2 is used to reserve Txn; 3) The slot increment 3 is used to reserve ACK slots.

b) The ACK time slot offset should be recalculated in the Txn-1 phase, and the communication status should be updated as follows: 1) Time slot increment 1 reserves Txn; 2) Time slot increment 2 reserves ACK time slot; 3) Set the time slot increment 3 to 0.

c) The ACK offset should be recalculated during the Txn phase, and the communication status should be updated as follows: 1) Time slot increment 1 reserves an ACK time slot; 2) Set time slot increments 2 and 3 to 0. 5.10.4.1.4 Confirmation The receiving station returns an acknowledgment message containing an ACK/NAK mask field in the ACK time slot, indicating whether the MITDMA packet group has been sent. Successful transmission. If there are any data blocks that failed to transmit, the transmitting device should retransmit the corresponding data blocks (always from single-slot RATDMA data blocks). (Retransmission started)

5.10.4.2 Message Retransmission 5.10.4.2.1 Broadcast Message Retransmission Reservation broadcast messages can be transmitted multiple times; retransmissions should be initiated within 3 minutes of the initial transmission. When retransmitting, the retransmission flag is set to [value missing].

1.The session ID is consistent with the initial transmitted message. After receiving a retransmitted message, the receiving device should determine its identity based on the block identifier and the previously received session ID. Compare consistent messages; if there are previously unreceived or failed verification blocks, they should be combined. If the MITDMA transmit data link... Once all data blocks are complete, they should be output via PI. After data is output from PI, the device should ignore subsequent retransmissions with the same session ID. The scheduled retransmission of broadcast messages should be completed within 20 minutes after the start of the first data block transmission. 5.10.4.2.2 Addressing Message Retransmission 5.10.4.2.2.1 Retransmit data blocks after confirmation Once the transmitting device receives the acknowledgment message, if there are data blocks that need to be retransmitted, the device should initiate a new MITDMA data packet group. The initial transmission used RATDMA for access, and subsequent transmissions used MITDMA to reserve retransmission and ACK time slots. Data was transmitted during retransmission. The block should also meet the following conditions.

a) Set the retransmission flag to 1;

b) The session ID is consistent with the initial transmitted message;

c) The data block identifier is consistent with the data block number in the MITDMA chain of the initial launch;

d) The transport block counter only counts the number of retransmitted data blocks. The ACK time slot reservation mechanism is the same as the initial transmission. In the ACK message, the bit mapped to the retransmission data block identifier should indicate whether the data is... The transmission is successful; all other bits are set to

0.During retransmission, the 0th data block of the message should be transmitted first, regardless of whether that data block has already been transmitted. Successful transmission. If the 0th data block has been successfully transmitted during the transmission process, the LSB in the ACK should be set to

5.11 Network Layer

5.11.1 General Requirements The network layer is used in the following situations.

a) Establish and maintain a channel connection;

b) Message priority assignment management;

c) Allocation of transmit packets between channels;

d) Resolving data link congestion.

5.11.2 Solutions to Data Link Congestion The ASM channel load should be tested individually within the past 1-minute window (2250 time slots). The silence time is after completing a single non-MITDMA ASM channel transmission or a complete MITDMA transmission including retransmissions, ASM The station should wait a specific time before scheduling other launches. The selection interval used to find candidate transmission slots is after the quiet period. start.

5.11.3 Time Slot Selection When ASM and AIS are Co-located The time slot selection process is shown in Figure 4. The selection of time slots should meet the following rules.

1.Both ASM channels are idle, and AIS1 and AIS2 are also idle. This rule can prevent the loss of received data.

2.Both ASM channels are idle, and one AIS channel is available while the other AIS channel is idle.

3.Both ASM channels are idle, and both AIS channels are available.

4.The ASM channel used for transmission is idle, and the data expected to be received on the other ASM channel is not closely related to this device. It is closed, and both AIS channels are available. Available AIS time slots should comply with the relevant provisions of ITU-R M.1371-5 and should be determined only from the eight furthest stations that meet the SI range. The station was selected, and then randomly chosen from the 8 furthest candidate stations. For messages exceeding one time slot, when selecting a candidate time slot, the candidate time slot should be the first time slot of a consecutive time slot block, and this time slot... All time slots in the block should meet the above selection criteria. If a station cannot find a sufficient number of candidate time slots, the station should not transmit. The shot should be fired and then re-passed.

6.1.1 Normal Test Conditions

6.1.1.1 Temperature and Humidity The temperature and humidity ranges are as follows:

a) Temperature. 15°C~35°C;

b) Relative humidity. 20%~75%.

6.1.1.2 Power Supply The normal supply voltage for testing should not exceed ±3% of the nominal voltage specified by the manufacturer.

6.1.2 Extreme Test Conditions Testing under extreme conditions should combine high temperature (55°C) with the upper limit of the supply voltage, and low temperature (-15°C) with the lower limit of the supply voltage. The electrical voltage is applied simultaneously. During type testing of battery-powered devices, the device's power supply can be replaced by a test power supply capable of generating normal or extreme test results. Voltage.

6.2 Standard Testing Environment

6.2.1 Test Channel and Simulated Target The EUT should be tested in a standard test environment that simulates and records VDL messages. The standard test environment should be capable of running ASM. Simultaneous receive and transmit functionality on AIS 1 and ASM

2.The standard test environment should include simulated targets running on the AIS channel. The objectives should consist of the following categories.

a) Category A shipboard equipment;

b) Category B "CS" shipboard equipment;

c) Category B "SO" shipboard equipment;

d) AIS base station;

e) AIS navigation aid stations;

f) Airborne equipment;

g) Positioning device;

h) ASM shipboard equipment;

i) ASM base station. The signal level at the RF input port of the EUT should be at least -100dBm. The standard test environment should continuously monitor the data emitted by the EUT on the VDL and the data output on the PI. The test environment should have The ability to input data to the EUT via PI.