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 |