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PortVision CE0 blog discusses benefits and limitations<br />

of Automatic Identification Systems (AIS)<br />

By Dean Rosenberg,<br />

CEO, Portvision<br />

As many of the readers of this<br />

blog already know, Automatic<br />

Identification System (AIS) is<br />

a VHF protocol that has been<br />

mandated on large vessels by<br />

IMO for collision avoidance<br />

and to enhance navigation since<br />

2005. Every vessel over 300 gross<br />

tons (or over 65 feet in the USA)<br />

carries an AIS transponder that<br />

receives broadcasts from nearby<br />

vessels, and also transmits identifying<br />

information about the<br />

vessel carrying the transponder.<br />

Information including a ship’s location,<br />

speed, and identifying information<br />

is transmitted multiple<br />

times per minute when a vessel is<br />

underway, and every few minutes<br />

when docked. You can view all<br />

details associated with the AIS<br />

specification at the USCG Navigation<br />

Center website.<br />

Once AIS became a global<br />

standard, the industry realized<br />

that in addition to leveraging<br />

the safety benefits of AIS in the<br />

wheelhouse, organizations could<br />

also drive significant value in<br />

their shore-side operations by<br />

using AIS to increase visibility<br />

and transparency to vessel movements<br />

around the world. Port-<br />

Vision launched its web-based<br />

service in 2007, and has since expanded<br />

to provide global coverage<br />

with a network of AIS receivers<br />

around the world.<br />

The challenge with a shorebased<br />

AIS service is that an individual<br />

AIS receiver is limited<br />

Photo: Institute of Aeronautical Technology<br />

to about a 50 mile radius. Ship<br />

tracking through shore-based<br />

(also known as “terrestrial”) AIS<br />

requires that each vessel be within<br />

50 miles of an AIS receiver in<br />

order to be tracked in the system.<br />

Terrestrial AIS provide significant<br />

value to users, including<br />

providing near-real-time vessel<br />

tracking when vessels are near<br />

shore. However, once a ship is<br />

in open water, terrestrial AIS<br />

becomes less effective. Initially,<br />

PortVision took steps to increase<br />

14

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