Message interface¶
pyais supports all message types. But it can currently not decode message specific payloads. This should be done by the user.
This applies to messages of type 6, 8, 25, and 26. These messages have in common, that they contain unspecified binary payload.
Message type 6: data field with up to 920 bits of binary payload
Message type 8: data field with up to 952 bits of binary payload
Message type 26: data field with up to 128 bits of binary payload
Message type 27: data fiield with up to 1004 bits of binary payload
The decoding of the binary payload is message dependent and varies between different systems. If you want to decode the binary payload of message type 6, you firstly would have to look at the dac (Designated Area Code) and the fid (Functional ID). Dependening of their values, you would know, how to interpret the payload.
There are a lot of different application-specific messages, which are more or less standardized.
Therefore pyais does not even try to decode the payload. Instead, you can access the raw payload
# Parse of message of type 8
msg = NMEAMessage(b"!AIVDM,1,1,,A,85Mwp`1Kf3aCnsNvBWLi=wQuNhA5t43N`5nCuI=p<IBfVqnMgPGs,0*47").decode()
payload = msg.data
The data is stored as raw bytes to make it easy to post process such binary payload. The lib also includes some handy helper functions to transform bytes to bits and vice versa:
from pyais.utils import bits2bytes, bytes2bits
bits2bytes('00100110') #=> b'&'
bytes2bits(b'&').to01() #=> '00100110'
NMEA messages¶
The NMEASentence is the first level of abstraction during parsing/decoding.
Every instance of NMEASentence has a fixed set of attributes:
msg = NMEASentence(b"!AIVDM,1,1,,A,15Mj23P000G?q7fK>g:o7@1:0L3S,0*1B")
msg.raw # => Raw decoded message as :byte:
msg.delimiter # => Start delimiter. Normally $ or ?
msg.data_fields # => NMEA payload. Interpretation varies depending on the NMEA sentence type
msg.talker_id # => two letter talker ID
msg.type # => three-letter type code.
msg.checksum # => NMEA sentence checksum. 8-bit XOR of all characters
msg.is_valid # => Check if checksum valid
msg.wrapper_msg # => Optional encapsulating message
This class is not meant to be instantiated directly. Instead, an inheriting class should subclass from it. Such a child class then defines the sentence specific logic.
pyais currently supports two NMEA sentence types:
GatehouseSentence: wrapper messages that hold additional meta data.
AISSentence: AIS messages
Gatehouse wrappers¶
Some AIS messages have so-called Gatehouse wrappers. These encapsulating messages contain extra information, such as time and checksums. Some readers also process these. See some more documentation [here](https://www.iala-aism.org/wiki/iwrap/index.php/GH_AIS_Message_Format).
As an example, see the following, which is followed by a regular !AIVDM message
`
$PGHP,1,2020,12,31,23,59,58,239,0,0,0,1,2C*5B
`
Such messages are parsed by pyais only when using any of the classes from pyais.stream. e.g. FileReaderStream or TCPStream.
Such additional information can then be accessed by the .wrapper_msg of every NMEASentence. This attribute is None by default.
Communication State¶
The ITU documentation provides details regarding the Time-division multiple access (TDMA) synchronization.
Such details include information used by the slot allocation algorithm (either SOTDMA or ITDMA) including their synchronization state.
This information can be found in the last 19 data-bits of some messages.
The following messages have the SOTDMA communication state:
Type 1
Type 2
Type 4
Type 9
Type 11
Type 18
The following messages have the ITDMA communication state:
Type 3
Type 18
These messages have in common that they have the .radio attribute. This attribute holds the raw value of the last 19 data-bits.
Further details can be retrieved by using one of the following methods:
.is_sotdma(): Returns True when using the SOTDMA algorithm
.is_itdma(): Returns True when using the ITDMA algorithm
get_communication_state(): information used by the slot allocation algorithm as a dictionary
Example:
msg = '!AIVDM,1,1,,A,B69Gk3h071tpI02lT2ek?wg61P06,0*1F'
decoded = decode(msg)
print("The raw radio value is:", decoded.radio)
print("Communication state is SOTMDA:", decoded.is_sotdma)
print("Communication state is ITDMA:", decoded.is_itdma)
pretty_json = functools.partial(json.dumps, indent=4)
print("Communication state:", pretty_json(decoded.get_communication_state()))
All other messages do not contain any details about the communication state. Therefore, the methods mentioned above are not available for these messages.
Message classes¶
There are 27 different types of AIS messages. Each message has different attributes and is encoded/decoded differently depending of the AIS standard. But, there are some things that all messages do have in common:
- When decoding:
if the message payload has fewer bits than would be needed to decode every field, the remaining fields are set to None
- When encoding:
you should use MessageType1.create(mmsi=123, …) for every message, as it sets default values for missing attributes.
MessageType1.create(…) always needs at least the mmsi keyword
if you create the instance directly e.g. MessageType1(mmsi=1, …), you need to provide every possible attribute, otherwise a TypeError is raised
- MessageType1
AIS Vessel position report using SOTDMA (Self-Organizing Time Division Multiple Access) Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_types_1_2_and_3_position_report_class_a
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 1
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- status
type: <class ‘int’>
bit-width: 4
default: 0
- turn
type: <class ‘float’>
bit-width: 8
default: TurnRate.NO_TI_DEFAULT
- speed
type: <class ‘float’>
bit-width: 10
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- course
type: <class ‘float’>
bit-width: 12
default: 0
- heading
type: <class ‘int’>
bit-width: 9
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- maneuver
type: <class ‘int’>
bit-width: 2
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 3
default: b’’
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 19
default: 0
- MessageType2
AIS Vessel position report using SOTDMA (Self-Organizing Time Division Multiple Access) Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_types_1_2_and_3_position_report_class_a
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 1
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- status
type: <class ‘int’>
bit-width: 4
default: 0
- turn
type: <class ‘float’>
bit-width: 8
default: TurnRate.NO_TI_DEFAULT
- speed
type: <class ‘float’>
bit-width: 10
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- course
type: <class ‘float’>
bit-width: 12
default: 0
- heading
type: <class ‘int’>
bit-width: 9
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- maneuver
type: <class ‘int’>
bit-width: 2
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 3
default: b’’
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 19
default: 0
- MessageType3
AIS Vessel position report using ITDMA (Incremental Time Division Multiple Access) Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_types_1_2_and_3_position_report_class_a
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 1
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- status
type: <class ‘int’>
bit-width: 4
default: 0
- turn
type: <class ‘float’>
bit-width: 8
default: TurnRate.NO_TI_DEFAULT
- speed
type: <class ‘float’>
bit-width: 10
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- course
type: <class ‘float’>
bit-width: 12
default: 0
- heading
type: <class ‘int’>
bit-width: 9
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- maneuver
type: <class ‘int’>
bit-width: 2
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 3
default: b’’
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 19
default: 0
- MessageType4
AIS Vessel position report using SOTDMA (Self-Organizing Time Division Multiple Access) Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_4_base_station_report
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 4
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- year
type: <class ‘int’>
bit-width: 14
default: 1970
- month
type: <class ‘int’>
bit-width: 4
default: 1
- day
type: <class ‘int’>
bit-width: 5
default: 1
- hour
type: <class ‘int’>
bit-width: 5
default: 0
- minute
type: <class ‘int’>
bit-width: 6
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- epfd
type: <class ‘int’>
bit-width: 4
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 10
default: b’’
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 19
default: 0
- MessageType5
Static and Voyage Related Data Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_5_static_and_voyage_related_data
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 5
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- ais_version
type: <class ‘int’>
bit-width: 2
default: 0
- imo
type: <class ‘int’>
bit-width: 30
default: 0
- callsign
type: <class ‘str’>
bit-width: 42
default:
- shipname
type: <class ‘str’>
bit-width: 120
default:
- ship_type
type: <class ‘int’>
bit-width: 8
default: 0
- to_bow
type: <class ‘int’>
bit-width: 9
default: 0
- to_stern
type: <class ‘int’>
bit-width: 9
default: 0
- to_port
type: <class ‘int’>
bit-width: 6
default: 0
- to_starboard
type: <class ‘int’>
bit-width: 6
default: 0
- epfd
type: <class ‘int’>
bit-width: 4
default: 0
- month
type: <class ‘int’>
bit-width: 4
default: 0
- day
type: <class ‘int’>
bit-width: 5
default: 0
- hour
type: <class ‘int’>
bit-width: 5
default: 0
- minute
type: <class ‘int’>
bit-width: 6
default: 0
- draught
type: <class ‘float’>
bit-width: 8
default: 0
- destination
type: <class ‘str’>
bit-width: 120
default:
- dte
type: <class ‘bool’>
bit-width: 1
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 1
default: b’’
- MessageType6
Binary Addresses Message Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_4_base_station_report
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 6
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- seqno
type: <class ‘int’>
bit-width: 2
default: 0
- dest_mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- retransmit
type: <class ‘bool’>
bit-width: 1
default: False
- spare_1
type: <class ‘bytes’>
bit-width: 1
default: b’’
- dac
type: <class ‘int’>
bit-width: 10
default: 0
- fid
type: <class ‘int’>
bit-width: 6
default: 0
- data
type: <class ‘bytes’>
bit-width: 920
default: b’’
- MessageType7
Binary Acknowledge Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_7_binary_acknowledge
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 7
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- mmsi1
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq1
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- mmsi2
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq2
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- mmsi3
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq3
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- mmsi4
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq4
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- MessageType8
Binary Acknowledge Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_8_binary_broadcast_message
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 8
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- dac
type: <class ‘int’>
bit-width: 10
default: 0
- fid
type: <class ‘int’>
bit-width: 6
default: 0
- data
type: <class ‘bytes’>
bit-width: 952
default: b’’
- MessageType9
Standard SAR Aircraft Position Report Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_9_standard_sar_aircraft_position_report
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 9
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- alt
type: <class ‘int’>
bit-width: 12
default: 0
- speed
type: <class ‘float’>
bit-width: 10
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- course
type: <class ‘float’>
bit-width: 12
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- reserved_1
type: <class ‘int’>
bit-width: 8
default: 0
- dte
type: <class ‘bool’>
bit-width: 1
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 3
default: b’’
- assigned
type: <class ‘bool’>
bit-width: 1
default: 0
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 20
default: 0
- MessageType10
UTC/Date Inquiry Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_10_utc_date_inquiry
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 10
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- dest_mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_2
type: <class ‘bytes’>
bit-width: 2
default: b’’
- MessageType11
UTC/Date Response Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_11_utc_date_response
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 4
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- year
type: <class ‘int’>
bit-width: 14
default: 1970
- month
type: <class ‘int’>
bit-width: 4
default: 1
- day
type: <class ‘int’>
bit-width: 5
default: 1
- hour
type: <class ‘int’>
bit-width: 5
default: 0
- minute
type: <class ‘int’>
bit-width: 6
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- epfd
type: <class ‘int’>
bit-width: 4
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 10
default: b’’
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 19
default: 0
- MessageType12
Addressed Safety-Related Message Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_12_addressed_safety_related_message
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 12
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- seqno
type: <class ‘int’>
bit-width: 2
default: 0
- dest_mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- retransmit
type: <class ‘bool’>
bit-width: 1
default: False
- spare_1
type: <class ‘bytes’>
bit-width: 1
default: b’’
- text
type: <class ‘str’>
bit-width: 936
default:
- MessageType13
Identical to type 7
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 7
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- mmsi1
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq1
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- mmsi2
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq2
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- mmsi3
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq3
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- mmsi4
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- mmsiseq4
type: (<class ‘int’>, <class ‘str’>)
bit-width: 2
default: 0
- MessageType14
Safety-Related Broadcast Message Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_14_safety_related_broadcast_message
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 14
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- text
type: <class ‘str’>
bit-width: 968
default:
- MessageType15
Interrogation Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_15_interrogation
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 15
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- mmsi1
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- type1_1
type: <class ‘int’>
bit-width: 6
default: 0
- offset1_1
type: <class ‘int’>
bit-width: 12
default: 0
- spare_2
type: <class ‘bytes’>
bit-width: 2
default: b’’
- type1_2
type: <class ‘int’>
bit-width: 6
default: 0
- offset1_2
type: <class ‘int’>
bit-width: 12
default: 0
- spare_3
type: <class ‘bytes’>
bit-width: 2
default: b’’
- mmsi2
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- type2_1
type: <class ‘int’>
bit-width: 6
default: 0
- offset2_1
type: <class ‘int’>
bit-width: 12
default: 0
- spare_4
type: <class ‘bytes’>
bit-width: 2
default: b’’
- MessageType16
Assignment Mode Command Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_16_assignment_mode_command
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 16
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- mmsi1
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- offset1
type: <class ‘int’>
bit-width: 12
default: 0
- increment1
type: <class ‘int’>
bit-width: 10
default: 0
- mmsi2
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: 0
- offset2
type: <class ‘int’>
bit-width: 12
default: 0
- increment2
type: <class ‘int’>
bit-width: 10
default: 0
- MessageType17
DGNSS Broadcast Binary Message Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_17_dgnss_broadcast_binary_message
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 17
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- lon
type: <class ‘float’>
bit-width: 18
default: 0
- lat
type: <class ‘float’>
bit-width: 17
default: 0
- spare_2
type: <class ‘bytes’>
bit-width: 5
default: b’’
- data
type: <class ‘bytes’>
bit-width: 736
default: b’’
- MessageType18
Standard Class B CS Position Report Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_18_standard_class_b_cs_position_report
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 18
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- reserved_1
type: <class ‘int’>
bit-width: 8
default: 0
- speed
type: <class ‘float’>
bit-width: 10
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- course
type: <class ‘float’>
bit-width: 12
default: 0
- heading
type: <class ‘int’>
bit-width: 9
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- reserved_2
type: <class ‘int’>
bit-width: 2
default: 0
- cs
type: <class ‘bool’>
bit-width: 1
default: 0
- display
type: <class ‘bool’>
bit-width: 1
default: 0
- dsc
type: <class ‘bool’>
bit-width: 1
default: 0
- band
type: <class ‘bool’>
bit-width: 1
default: 0
- msg22
type: <class ‘bool’>
bit-width: 1
default: 0
- assigned
type: <class ‘bool’>
bit-width: 1
default: 0
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- radio
Further decoded by .get_communication_state()
type: <class ‘int’>
bit-width: 20
default: 0
- MessageType19
Extended Class B CS Position Report Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_19_extended_class_b_cs_position_report
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 19
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- reserved_1
type: <class ‘int’>
bit-width: 8
default: 0
- speed
type: <class ‘float’>
bit-width: 10
default: 0
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- course
type: <class ‘float’>
bit-width: 12
default: 0
- heading
type: <class ‘int’>
bit-width: 9
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- reserved_2
type: <class ‘int’>
bit-width: 4
default: 0
- shipname
type: <class ‘str’>
bit-width: 120
default:
- ship_type
type: <class ‘int’>
bit-width: 8
default: 0
- to_bow
type: <class ‘int’>
bit-width: 9
default: 0
- to_stern
type: <class ‘int’>
bit-width: 9
default: 0
- to_port
type: <class ‘int’>
bit-width: 6
default: 0
- to_starboard
type: <class ‘int’>
bit-width: 6
default: 0
- epfd
type: <class ‘int’>
bit-width: 4
default: 0
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- dte
type: <class ‘bool’>
bit-width: 1
default: 0
- assigned
type: <class ‘bool’>
bit-width: 1
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 4
default: b’’
- MessageType20
Data Link Management Message Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_20_data_link_management_message
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 20
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- offset1
type: <class ‘int’>
bit-width: 12
default: 0
- number1
type: <class ‘int’>
bit-width: 4
default: 0
- timeout1
type: <class ‘int’>
bit-width: 3
default: 0
- increment1
type: <class ‘int’>
bit-width: 11
default: 0
- offset2
type: <class ‘int’>
bit-width: 12
default: 0
- number2
type: <class ‘int’>
bit-width: 4
default: 0
- timeout2
type: <class ‘int’>
bit-width: 3
default: 0
- increment2
type: <class ‘int’>
bit-width: 11
default: 0
- offset3
type: <class ‘int’>
bit-width: 12
default: 0
- number3
type: <class ‘int’>
bit-width: 4
default: 0
- timeout3
type: <class ‘int’>
bit-width: 3
default: 0
- increment3
type: <class ‘int’>
bit-width: 11
default: 0
- offset4
type: <class ‘int’>
bit-width: 12
default: 0
- number4
type: <class ‘int’>
bit-width: 4
default: 0
- timeout4
type: <class ‘int’>
bit-width: 3
default: 0
- increment4
type: <class ‘int’>
bit-width: 11
default: 0
- MessageType21
Aid-to-Navigation Report Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_21_aid_to_navigation_report
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 21
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- aid_type
type: <class ‘int’>
bit-width: 5
default: 0
- name
type: <class ‘str’>
bit-width: 120
default:
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- lon
type: <class ‘float’>
bit-width: 28
default: 0
- lat
type: <class ‘float’>
bit-width: 27
default: 0
- to_bow
type: <class ‘int’>
bit-width: 9
default: 0
- to_stern
type: <class ‘int’>
bit-width: 9
default: 0
- to_port
type: <class ‘int’>
bit-width: 6
default: 0
- to_starboard
type: <class ‘int’>
bit-width: 6
default: 0
- epfd
type: <class ‘int’>
bit-width: 4
default: 0
- second
type: <class ‘int’>
bit-width: 6
default: 0
- off_position
type: <class ‘bool’>
bit-width: 1
default: 0
- reserved_1
type: <class ‘int’>
bit-width: 8
default: 0
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- virtual_aid
type: <class ‘bool’>
bit-width: 1
default: 0
- assigned
type: <class ‘bool’>
bit-width: 1
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 1
default: b’’
- name_ext
type: <class ‘str’>
bit-width: 88
default:
- MessageType23
Group Assignment Command Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_23_group_assignment_command
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 23
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- spare_1
type: <class ‘bytes’>
bit-width: 2
default: b’’
- ne_lon
type: <class ‘float’>
bit-width: 18
default: 0
- ne_lat
type: <class ‘float’>
bit-width: 17
default: 0
- sw_lon
type: <class ‘float’>
bit-width: 18
default: 0
- sw_lat
type: <class ‘float’>
bit-width: 17
default: 0
- station_type
type: <class ‘int’>
bit-width: 4
default: 0
- ship_type
type: <class ‘int’>
bit-width: 8
default: 0
- spare_2
type: <class ‘bytes’>
bit-width: 22
default: b’’
- txrx
type: <class ‘int’>
bit-width: 2
default: 0
- interval
type: <class ‘int’>
bit-width: 4
default: 0
- quiet
type: <class ‘int’>
bit-width: 4
default: 0
- spare_3
type: <class ‘bytes’>
bit-width: 6
default: b’’
- MessageType27
Long Range AIS Broadcast message Src: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_27_long_range_ais_broadcast_message
- Attributes:
- msg_type
type: <class ‘int’>
bit-width: 6
default: 27
- repeat
type: <class ‘int’>
bit-width: 2
default: 0
- mmsi
type: (<class ‘int’>, <class ‘str’>)
bit-width: 30
default: None
- accuracy
type: <class ‘bool’>
bit-width: 1
default: 0
- raim
type: <class ‘bool’>
bit-width: 1
default: 0
- status
type: <class ‘int’>
bit-width: 4
default: 0
- lon
type: <class ‘float’>
bit-width: 18
default: 0
- lat
type: <class ‘float’>
bit-width: 17
default: 0
- speed
type: <class ‘float’>
bit-width: 6
default: 0
- course
type: <class ‘float’>
bit-width: 9
default: 0
- gnss
type: <class ‘bool’>
bit-width: 1
default: 0
- spare_1
type: <class ‘bytes’>
bit-width: 1
default: b’’