README.md

NMEA-AIS-Generator

The nmea-ais-generator is a simple Automatic Identification System (AIS) messages generator. This script can be useful for testing applications or systems that require some AIS raw data.

Features

• The NMEA data generated by the script (NMEA 0183 format) is sent to clients via UDP packets.
• Individual clients' data (IP address & UDP port) is loaded from the data/clients.json file. Max number of clients is 10.
• By default, the initial AIS tracks data is loaded from data/tracks.json file.
• Both clients and tracks data is validated during loading.
• The AIVDM NMEA 0183 type sentences are supported. AIVDM- sentence received data from other vessels.
• Script generates following AIS messages:
  • Message type 1 - Position Report Class A;
  • Message type 5 - Static and Voyage Related Data.
• Scripts options:
  • the initial AIS data can be loaded from specified JSON file;
  • the generated NMEA output data can also be displayed on the CLI terminal;
  • the updated AIS data can be saved to a new JSON file on terminating of the script.

Terminal output example:

# AIS type 1 message
!AIVDM,1,1,,A,13q5W0PP1fQEpJVO9V>pIVgp0D7k,0*66
# AIS type 5 message
!AIVDM,2,1,1,A,53q5W0`00001=;O??20d4l62222222222222220T0000040HtNQi0CTjp888,0*0C
!AIVDM,2,2,1,A,88888888880,2*25

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Getting Started

Use the following instructions to run the script on your local machine.

Requirements

Python third party packages:

• pyproj
• pydantic
• aenum

Before running the script, the following files should be properly updated (files are placed in the data folder):

• clients.json - the IP address (hostname) and port pair to which the UDP packet should be sent;
• tracks.json - object data that will be converted to NMEA format and then sent

Example files can be found in the root directory of the project.

Installation with venv

The script can be build and run locally with virtualenv tool. Run following commands in order to create virtual environment and install the required packages.

$ virtualenv venv
$ source venv/bin/activate
(venv) $ pip install -r requirements.txt

Running the script

Script usage:

(venv) $ python main.py -h
usage: main.py [-h] [-f FILENAME] [-s SAVE] [-o]

The NMEA AIS data generating script

optional arguments:
  -h, --help            show this help message and exit
  -f FILENAME, --filename FILENAME
                        JSON filename with initial AIS tracks data (default: data/tracks.json)
  -s SAVE, --save SAVE  JSON filename to which the updated AIS data should be saved when the script exits
  -o, --output          Display NMEA AIS data on the terminal screen

You can start the script using one of the following commands:

# Run script with default options - data loaded from "tracks.json" file
(venv) $ python main.py
# Run script and display generated NMEA AIS output data on the CLI terminal
(venv) $ python main.py -o
# Run script and save updated AIS data to 'updated-tracks.json' file
(venv) $ python main.py -s updated-tracks.json
# Run script and load initial data from 'updated-tracks.json' file
(venv) $ python main.py -f updated-tracks.json

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References

• AIVDM/AIVDO protocol decoding
• AIS Standard
• Sample AIVDM messages