AIS Dispatcher

The time window can be configured between 0 and 300 seconds. 0 seconds means no downsampling. Downsampling reduces the outgoing traffic several times. Downsampling affects AIS messages 1,2,3,4,5,18,19,24 only!

Example of use

The following example illustrates how AIS Dispatcher can forward NMEA messages from a single AIS receiver to AISHub.Net, other destination and local ShipPlotter running on the same machine.

RAW AIS DATA SAMPLE

We receive a lot of questions by software developers who need some raw AIS data to test their applications.
Here you can download a sample with raw AIS data from AISHub. The file contains ~85K messages (3 minute live AISHub feed).
 AIS Sample Download

AIS Dispatcher - Windows

Installation

Download AISDispatcher ZIP file and unzip it in a separate folder.

Start up

After the first start, the program runs with default configuration. You can place a shortcut to aisDispatcher.exe on your desktop or into the "Startup" folder for an automatic startup.

Configuration

The configuration dialog is displayed by pressing “Configuration” button on the main window. The “Configuration” dialog contains four configuration panels – "Input", "Output", "Google Earth"and "Miscellaneous".

"INPUT" Configuration

INPUT MODE

You can choose one of the following types of data input:

TCP	AISDispatcher creates TCP connection to the remote data source
UDP	AISDispatcher listens on the specified port
Serial	AISDispatcher receives data from a local serial port (or USB serial device)

TCP input (only if TCP input mode is selected)

• Remote IP – IP address (or domain name) of the remote data source (example: IP 192.168.1.102)
• Remote port – TCP port of the remote data source (example: port 4001)

UDP input (only if UDP input mode is selected)

• Local port – port on the local Windows machine, where AISDispatcher listens for incoming UDP packets (example: udp port 5000)

Serial input (only if Serial input mode is selected)

• COM port – serial port name (example: COM1)
• Baud rate – baud rate selection (example: 38400).

Serial input uses 8,N,1 serial settings, according to NMEA specification.

"OUTPUT" CONFIGURATION

UDP Output

Downsampling interval	time window of downsampling algorithm. For more details see: AIS Dispatcher – Description
Destinations	up to 12 destination IP addresses/ports. AISDispatcher forwards AIS data to all configured and enabled destinations. In our example, there are two destinations.
Filters	filtering by polygon and message types may be used for each destination

"GOOGLE EARTH" CONFIGURATION

Delete old vessels

Expriation time – AIS Dispatcher keeps list of all received vessels since the startup. Each minute, the application purges the list and removes the vessels with last packet timestamp older than the defined “expiration time”.

HTTP Server configuration

Host / Port – AIS Dispatcher listens for network connections from Google Earth clients on the specified host / port. When host is “0.0.0.0″ (by default), the application listens on all network interfaces.
Enable HTTP server – enable/disable the HTTP server
Allow localhost only - disables connection to all external interfaces. AIS Dispatcher listens for connections only from Google Earth clients started on the user’s PC.

KML / KMZ export

Enable – enable/disable the regular export of KML/KMZ file into the local hard drive. AISDispatcher saves the file in its installation directory, “kml_export” folder. The file is named “aisDispatcherSnapshot.kml” or “aisDispatcherSnapshot.kmz”.
Export interval – time interval between sequential KML/KMZ exports

Miscellaneous

Use ZIP compression - when ZIP compression is enabled, AISDispatcher generates KMZ instead of KML file format. In this case, the application consumes more CPU time, but reduces the network traffic several times. KMZ format also consumes more CPU time by the Google Earth client.
Show vessel names - displays all vessels names.

Delete old vessels

Expriation time – AIS Dispatcher keeps list of all received vessels since the startup. Each minute, the application purges the list and removes the vessels with last packet timestamp older than the defined “expiration time”.

HTTP Server configuration

Host / Port – AIS Dispatcher listens for network connections from Google Earth clients on the specified host / port. When host is “0.0.0.0″ (by default), the application listens on all network interfaces.
Enable HTTP server – enable/disable the HTTP server
Allow localhost only - disables connection to all external interfaces. AIS Dispatcher listens for connections only from Google Earth clients started on the user’s PC.

KML / KMZ export

Enable – enable/disable the regular export of KML/KMZ file into the local hard drive. AISDispatcher saves the file in its installation directory, “kml_export” folder. The file is named “aisDispatcherSnapshot.kml” or “aisDispatcherSnapshot.kmz”.
Export interval – time interval between sequential KML/KMZ exports

Miscellaneous

Use ZIP compression - when ZIP compression is enabled, AISDispatcher generates KMZ instead of KML file format. In this case, the application consumes more CPU time, but reduces the network traffic several times. KMZ format also consumes more CPU time by the Google Earth client.
Show vessel names - displays all vessels names.

"MISCELLANEOUS" CONFIGURATION

Auto connect on startup	automatically creates connection after the start of the application
Minimize to system tray on close	when pressing ALt+F4 or “X” button, the application is minimized to the system tray. It can be closed by clicking on the system tray with the right mouse button and selecting “Exit”.
Start application minimized	after startup, the application is minimized to the system tray
Show system tray hint	displays hint with the current status when mouse cursor hovers over the icon in the system tray
Dispatch VDM/VDO messages only	filters only VDM/VDO messages from AIS sources. If the filter is off, the AISDispatcher will forward all other NMEA messages (like GPS devices for example).
Don’t dispatch channel C	filters AIS channel C (secure AIS)

MAIN WINDOW

AIS Dispatcher’s main window contains connection controls and detailed statistics of the input data feed.

Input section

Mode	current input mode (TCP,UDP or serial) and connection parameters
Status	current connection status
“Start”/”Stop” buttons	connection control

Input statistics

Message counters and byte counters of the incoming data feed. For more information about the meaning of the fields, check the AIS specification.

Input statistics (by AIS message type 1..24)

There are 24 different types of AIS messages. This panel displays separate message counter for each message type. Additional details about each message type are displayed by hovering with the mouse over the counter.

Input statistics (by AIS message type 1..24)

Displays last received AIS messages

"Clear" button

Clears all counter

"Configuration" button

Displays configuration window described in the previous chapter

Output statistics

In/Out ratio - ratio between input and output data counters. This parameter shows the efficiency of the downsampling algorithm.
Bandwidth (kB/s) – average output bandwidth in Kilobytes per Second
Distinct vessels – current number of vessels kept in AIS Dispatcher memory buffer.

SYNOPSIS
 1. TCP client input:
 aisdispatcher -t -h -p -H ,,... [-x ] [-y ] [-D ] [-v]
 2. UDP input:
 aisdispatcher -u -h -p -H ,,... [-D ] [-v]
 3. Serial input:
 aisdispatcher -r -d -s -H ,,... [-D ] [-v]
 4. input:
 aisdispatcher -i -H ,,... [-D ] [-v]

AIS Dispatcher supports the native KML / KMZ format of Google Earth and listens for incomming connections from Google Earth clients.

The configuration of HTTP server parameters is described in AIS Dispatcher – Windows section.

The easiest way to view the AIS Dispatcher data via Google Earth is to open the file “AISDispatcher.kml” in the application folder. The file automatically redirects Google Earth to http://127.0.0.1:7080 and sets the refresh interval to 60 seconds.

 <?xml version="1.0" encoding="UTF-8"?>
 <kml xmlns="http://earth.google.com/kml/2.0">
 <Document>
 <visibility>1</visibility>
 <NetworkLink>
 <name>AIS Dispatcher</name>
 <flyToView>0</flyToView>
 <Url><href>http://127.0.0.1:7080</href>
 <refreshMode>onInterval</refreshMode>
 <refreshInterval>60</refreshInterval>
 <viewRefreshMode>never</viewRefreshMode>
 </Url>
 <refreshVisibility>1</refreshVisibility>
 </NetworkLink>
 </Document>
 </kml>

The connection can be established without AISDispatcher.kml file by selecting  “Add” / “Network link” menu in Google Earth application and entering the name of the connection and the URL (for example http://www.example.com:7080). The refresh interval has to be configured from the “Refresh” panel in the same dialog window.