IALA

VTS-generated/Synthetic targets

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