AIS Library in Erlang. Free software decoder library for the maritime AIS data format written in the Erlang programming language. This library can now decode the main part of the AIS sentence and the message types containing the "Common Navigation Block" as it is termed in the protocol decoding notes. This is sufficient to pick up location and direction of travel information from vessels. It can now also decode base station reports and work on the aid to navigation report is underway.
The information used to create this library is based heavily on the notes at http://catb.org/gpsd/AIVDM.html
There is now some sample data in the logs directory. The first batch was captured with a receiver located at South Queensferry.
AIS sentences extracted from this data, in combination with the online decoder at http://www.maritec.co.za/aisvdmvdodecoding.php is being used to construct the regression tests.
It is necessary to have a recent version of Erlang, the rebar3 build tool and (optionally) a make utiility installed in order to build the software.
The software can be built (on a Linux platform) as follows:
# make
This will also run the unit tests, generate module documentation and run the dialyzer static analysis tool.
The easiest way to play around with the library is from the Erlang interactive shell. To start the shell and set up the paths to the compiled files, run
# rebar3 shell
From the Erlang shell, it is possible to parse the supplied log file, e.g.
1> A = aisle:parse_file("logs/ais_squeensferry_advansea_rx_100_20161120.log").
This will return a list of decoded records (the message types that are not understood are skipped). The contents of these records can then be displayed in an easier to read form:
2> aisle:display(A).
Single sentences can be decoded and displayed in a similar manner:
3> B = aisle:decode("!AIVDM,1,1,,B,177KQJ5000G?tO`K>RA1wUbN0TKH,0*5C").
...
4> aisle:display(B).
...