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VTS-generated/Synthetic targets

Introduction/Additional information: 

This message should be used to transmit VTS or other types of synthetic targets.
This message can be variable in length, based on the amount of targets. The maximum number
of Targets transmitted in one message should not exceed four (4).

A VTS-generated or synthetic target should only be used when the position of the target
is known.

Permitted as from: 
01/06/2010
Registrant: 
IMO Circ. 289
Physical link: 
AIS
Message number (0=VDES-VDE): 
8
DAC or VPFI: 
1
FI / Message ID: 
17
State: 
in force
State link: 
Pseudo-AIS targets
Number of slots (max): 
3
Last modified: 
29/01/2021 - 23:18
Details: 
Table 6.1
VTS-generated/Synthetic targets
 
Parameter No. of bits Description
Message ID 6 Identifier for Message 8; always 8.
Repeat Indicator 2 Used by the repeater to indicate how many times a message has been repeated.
0 - 3
0 = default
3 = do not repeat anymore
Source ID 30 Name of source station.
Spare 2 Not used. Set to zero.
IAI 16 DAC = 001; FI =17
Target 1 120 Refer to Table 6.2
Target 2 120 Optional; refer to Table 6.2
Target 3 120 Optional; refer to Table 6.2
Target 4 120 Optional; refer to Table 6.2
Total max 536 Occupies 2 - 3 slots
 
 
 
Table 6.2
Structure of the target
 
Parameter No. of bits Description
Type of Target
Identifier
 		 2 Identifier Type:
0 = The target identifier is the MMSI number
1 = The target identifier is the IMO number.
2 = The target identifier is the call sign
3 = Other (default)
Target Identifier
 		 42
 		 The Target Identifier depends on Type of Target Identifier (see above). When call sign or vessel name is used, it should be inserted using 6-bits ASCII characters. When MMSI or IMO number is used, the least significant bit should equal bit zero of the Target Identifier.
If the target identity is unknown, Type of Target Identifier should be set to "3" and Target Identifier to "@@@@@@@".
Spare 4 Spare. Set to zero.
Latitude 24 Latitude in 1/1,000 min, ±90 degrees as per 2's complement (North = positive, South = negative).
91 degrees = not available = default
Longitude 25 Longitude in 1/1,000 min, ±180 degrees as per 2's complement (East = positive, West = negative).
181 = not available = default
Course-over-ground (COG) 9 COG in degrees, in 1 degree steps.
0 - 359
360 = not available = default
Time Stamp 6 UTC time when the report was generated.
0 - 59 seconds
60 = not available = default
Speed-over-ground (SOG) 8 SOG in knots, in 1 knot steps.
0 - 254
255 = not available = default
Total 120