AIS Factsheet -

Different AIS Messages:

Spire AIS data sample files contain records representing different types of AIS messages.

Message Types 1, 2, 3, 18, 19, 27 are position messages and contain values in the position related fields.

Message Types 5 & 24 are static voyage messages and contain values in the static details and voyage related fields.

To identify the Name, IMO number or type of ships related to the AIS Position reports, the MMSI number must be used to join together the 2 different sets of AIS data.

IE if position reports are recorded against MMSI 636018333 in AIS message type 1 then the IMO and name of that vessel is discovered by looking for AIS message type 5 reported using the same MMSI number as shown below.

Table showing the distribution of values in key fields from different AIS messages

AIS Data Sample File Column Descriptions:

ColumnData TypeDescriptions
created_atdateISO 8601 formatted timestamp in UTC of the time the vessel record was created
timestampstringISO 8601 formatted timestamp in UTC of the time the AIS message was transmitted
mmsiintegerThe  Maritime Mobile Service Identity of the vessel transmitting the AIS message

Possible values:

000000000 – 999999999

msg_typeintegerAIS message type

Common values:

1, 2, 3, 5, 18, 19, 24, 27

AIS message types are explained in more details here

latitudefloatVessel latitude in degrees

(North = positive, South = negative)

range -90 to +90

longitudefloatVessel longitude in degrees

(East = positive, West = negative)

range = -180 to +180

speednumberVessel speed over ground represented in knots

Possible values:

0 – 102.2 knots, 102.3 (not available)

coursenumberVessel course over ground in degrees

Possible values:

0 – 359.9 degrees, 360.0 (not available)

headingnumberVessel true heading in degrees

Possible values:

0 – 359 degrees, 511 (not available)

rot integerVessel rate of turn

Possible values:

-127 – 127; -128 (not available)

imointegerIMO number of the ship

Unique International Maritime Organization number for the vessel that stays with the ship for it’s life

valid values 7 digit number

namestringVessel name
call_signstringVessel call sign
flagstringVessel flag

Possible values:

000000000 – 999999999

draughtfloatVessel draught represented in 1/10 meters

Possible values:

0.1 – 255, 0 (not available; default)

ship_and_cargo_typeintegerVessel ship and cargo type code

Some common values:

30 (fishing vessel), 52 (tug boat), 70 (cargo/fishing ship)

more information on determining the ship type is detailed here

lengthnumberVessel length extracted from ship dimensions to_bow and to_stern in meters
widthnumberVessel width extracted from ship dimensions to_portside and to_starboard in meters
etastringVessel estimated time of arrival as entered by the captain, represented in ISO 8601 format

Possible values:

Month: 1 – 12, 0 (not available; default); Day: 1 – 31, 0 (not available; default); Hour: 0 – 23, 24 (not available; default); Minute: 0 – 59, 60 (not available; default)

destinationstringVessel destination as entered by the vessel captain
statusintegerVessel navigation status

Some common values:

0 (under way using engine), 1 (at anchor), 3 (restricted maneuverability), 7 (engaged in fishing), 15

maneuverintegerVessel maneuver code

Valid values:

0 (not available; default), 1 (not engaged in special maneuver), 2 (engaged in special maneuver)

accuracyintegerVessel GPS geo location accuracy in meters

Possible values:

1 (high, <=10 meters); 0 (low, >10 meters, default)

to_bowintegerDistance from AIS transponder to the bow side edge in meters (Hull dimension A)
to_sternintegerDistance from AIS transponder to the stern side edge in meters (Hull dimension B)
to_portsideintegerDistance from AIS transponder to the port side edge in meters (Hull dimension C)
to_starboardintegerDistance from AIS transponder to the starbord side edge in meters (Hull dimension D)
collection_typestringHow the message was captured

Possible values:

satellite or terrestrial or dynamic

Spire Documentation

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Spire Sales Engineering Team
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