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):

DAC or VPFI:

FI / Message ID:

State:

in force

State link:

Pseudo-AIS targets [1]

Number of slots (max):

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