AIS CapCalc

AIS basestations are primarily used ashore for traffic monitoring and management purposes, e.g. by Vessel Traffic Services (VTS). Due to the EU Directive 2002/59/EC of 27 June 2002 establishing a Community vessel traffic monitoring and information system, all member states bordering the sea are required to set up AIS basestations for collecting maritime traffic information. Similar systems are presently being built up in other parts of the world. In this context it is of interest, how many mobile and stationary AIS systems can be received by a single shore-based ‘physical AIS base station’. AIS CapCalc will provide the answer for user-defined traffic scenarios.


AIS CapCalc(J) shown below is made available on this web site for educational and scientific purposes and under exclusion of any form of warranty, what so ever. The author reserves the full copyright. Any form of commercial use requires a license by the author. AIS CapCalc reflects the AIS technical design by the end of 2005. If you accept these conditions, you may use AIS CapCalc now. Please make sure that Javascript is enabled in your browser. Please enter the number of vessels of your traffic scenario in the right column of the table. After a mouse click on ‘Compute’ the total bit rate (sum of both radio channels) will be displayed. The load of both radio channels relative to the maximum will be displayed in the field below. Please note that both figures are averages. Higher peak loads could occur. An ample spare capacity should be available, so that 18,400 bps or 100 % are never exceeded.

A more detailed calculation scheme including the most significant of the remaining message types, e.g. Class-B AIS, ATON AIS, SAR AIS, experimental Binary Messages is available from the author in form of an Excel spread sheet (AIS CapCalc E). Please ask the author for the conditions.


Ship at anchor or moored and not moving faster than 3 knots
Ship at anchor or moored and moving faster than 3 knots
Ship 0-14 knots
Ship 0-14 knots and changing course
Ship 14-23 knots
Ship 14-23 knots and changing course
Ship >23 knots
Ship >23 knots and changing course
Radio channel load [bps]:
Radio channel load [%]:

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Ingo Harre, Bremen, Germany, Content last modified on 2009/04/25