Physical link:
AIS
msg_ID:
9
Extended description:
Position report for airborne stations involved in SAR operations, only
Priority:
1
Access scheme:
SOTDMA
RATDMA
ITDMA
Communication state:
SOTDMA
ITDMA
Transmitted by:
Mobile station
This message should be used as a standard position report for aircraft involved in SAR operations. Stations other than aircraft involved in SAR operations should not transmit this message. The default reporting interval for this message should be 10 s.
TABLE 59[1]
Parameter | Number of bits | Description |
Message ID | 6 | Identifier for Message 9; always 9 |
Repeat indicator | 2 | Used by the repeater to indicate how many times a message has been repeated. See § 4.6.1, Annex 2; 0-3; 0 = default; 3 = do not repeat any more |
User ID | 30 | MMSI number |
Altitude (GNSS) | 12 | Altitude (derived from GNSS or barometric (see altitude sensor parameter below)) (m) (0-4 094 m) 4 095 = not available, 4 094 = 4 094 m or higher |
SOG | 10 | Speed over ground in knot steps (0-1 022 knots) 1 023 = not available, 1 022 = 1 022 knots or higher |
Position accuracy | 1 | 1 = high (£10 m) 0 = low (>10 m) 0 = default The PA flag should be determined in accordance with Table 50 |
Longitude | 28 | Longitude in 1/10 000 min (±180°, East = positive (as per 2’s complement), West = negative (as per 2’s complement); 181 = (6791AC0h) = not available = default) |
Latitude | 27 | Latitude in 1/10 000 min (±90°, North = positive (as per 2’s complement), South = negative (as per 2’s complement); 91 = (3412140h) = not available = default) |
COG | 12 | Course over ground in 1/10 = (0-3 599). 3 600 (E10h) = not available = default; 3 601-4 095 should not be used |
Time stamp | 6 | UTC second when the report was generated by the EPFS (0-59 or 60 if time stamp is not available, which should also be the default value or 61 if positioning system is in manual input mode or 62 if electronic position fixing system operates in estimated (dead reckoning) mode or 63 if the positioning system is inoperative) |
Altitude sensor | 1 | 0 = GNSS 1 = barometric source |
Spare | 7 | Not used. Should be set to zero. Reserved for future use |
DTE | 1 | Data terminal ready (0 = available 1 = not available = default) (see § 3.3.1) |
Spare | 3 | Not used. Should be set to zero. Reserved for future use |
Assigned mode flag | 1 | 0 = Station operating in autonomous and continuous mode = default 1 = Station operating in assigned mode |
RAIM-flag | 1 | RAIM flag of electronic position fixing device; 0 = RAIM not in use = default; 1 = RAIM in use see Table 50 |
Communication state selector flag | 1 | 0 = SOTDMA communication state follows 1 = ITDMA communication state follows |
Communication state | 19 | SOTDMA communication state (see § 3.3.7.2.1, Annex 2), if communication state selector flag is set to 0, or ITDMA communication state (see § 3.3.7.3.2, Annex 2), if communication state selector flag is set to 1 |
Number of bits | 168 |
[1] 1 Nautical mile = 1 852 metres.
1 knot = 1 852 m/h.
1 knot = 1 852 m/h.