Neist Point

Technics of the Light's

In Salutem Omnium
For the Safety of All
Neist Point - Isle of Skye
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© Composted by:
Bob Schrage
updated: 03-11-2017

Automatic Identificaion System (AIS)


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Use of AIS as an Aid to Navigation (AtoN)

> Northern Lighthouse Board (NLB) also provide AIS as an Aid to Navigation (AtoN), and are gradually extending the number of units deployed on buoys and lights as a component of the IMO e-Navigation initiative. NLB have access to a national network of AIS base stations which allows the organisation to monitor and assess vesselping around our coast, which is used as a tool to inform the review of AtoN provision and help identify the emergency marking requirements of wrecks and new hazards. NLB also are developing, in partnervessel with the other GLAs, the use of Virtual Aids to Navigation via AIS. Virtual AIS AtoN are used to mark new dangers/wrecks or in circumstances where a physical AtoN cannot be established. The AtoN does not physically exist and therefore will only be visible on display systems. It is important to bear in mind that the AIS information available to mariners will be dependent on their display system and not all transmitted information may be displayed.

Displays & Symbology

The IMO mandatory carriage requirement for the Class A1 AIS display is the Minimum Keyboard Display which displays the data in alphanumeric form. Of those vessels that are AIS equipped the displays available can range from no display on some Class B units, through the mandatory Class A MKD, to full ECDIS and Radar overlay. In the absence of ECDIS or Radar overlay users will not be able to fully utilise AIS AtoN functionality. There is also a variance of information that will be displayed by different manufacturers on ECDIS or Radar equipment. The symbology that may be displayed on nautical charts, display systems and MKD is summarised below.

Nautical Charts

On nautical charts AIS AtoN are indicated by a magenta circle surrounding the existing AtoN symbol and an adjacent legend stating AIS. The font will be straight for fixed AtoN and italic for floating AtoN.

Display Systems

Where AIS is provided as an overlay on ECDIS, Radar or other display systems AIS AtoN are indicated by a Diamond shape with crossed lines at the reported position of the AtoN. Where the AtoN is on station the diamond will be Blue and where the AtoN Off Station flag has been activated the diamond will be Red. In the case of a Virtual AIS AtoN there will be a V below the crossed lines.

Minimum Keyboard Display

The mandatory Minimum Keyboard Display (MKD) is only required to display data in alphanumeric form. Some MKD are units supplemented by a small graphical display. Exact presentation will vary but the layout opposite would be typical of MKD displays.

Message Types

AIS stations provided by the GLAs will transmit Message 21 and may also transmit Messages 8, 12 & 14.

Message 21 – Aids to Navigation report. This message will provide details of the Name, MMSI, Type and Position of the AtoN. In addition there will be an indication if the AtoN is off station, and of the status of the light, racon or other equipment.

Message 8 – Binary Broadcast Message. This message can be used to transmit the internationally agreed Met/Hydro message. Depending on the station, the message may contain details of Wind Speed & Direction, Wave Height, Direction & Period, Tidal height, and Visibility.

Messages 12 & 14 – Addressed & Broadcast Safety Related Messages. These messages can be used to supplement Message 8 for Met/Hydro messaging by providing a texting service and to provide additional information on the status of AtoNs in an area.

This page is under construction



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