Monitoring

NLB policy is to monitor all its active land and sea based Aids to Navigation at its Monitor Centre in Edinburgh. The correct functioning of all active Aids to Navigation i.e. all those that transmit as part of their function, whether it be light, sound or radio signal, will be monitored from Edinburgh giving improved system reliability and availability. The estate has 360 such Aids to Navigation of which more than 203 are at present monitored including buoys using GSM and AIS. Land based lights are monitored using a PSTN, UHF low and high power radio, GSM and satellite with AIS also to be used in future. See below for brief description of AIS.

The monitored data is transmitted around the corporate computer network using the web and it can be viewed anywhere a connection is available. Hot standby servers set up at Oban base will be used as a backup Monitor Centre in event of total failure in Edinburgh. This data can also be viewed remotely.

Satellite Monitoring

The use of long range UHF links is constantly reviewed and because of this further emphasis has been placed on the use of satellite networks for remote sites where GSM is unavailable. The technology required to operate AtoNs has led to a reduction in the amount of data transmitted. Therefore the data transmission cost by satellite is restricted whereas dedicated UHF links to a local base station require more equipment and generally more attention.

Satellite and full web based monitoring was introduced to NLB via commercial activity in the North Sea where NLB now operates, monitors and maintains lights on de-commissioned oil rigs. NLB has now installed the same equipment at Sule Skerry and Canna.

AIS Monitoring

NLB uses the international AIS (Automatic Identification System) to monitor both fixed and floating AtoNs. AIS principal function is navigation and collision avoidance for IMO SOLAS vessels using short messages in the Maritime Mobile VHF Band to exchange pertinent information. However messages are exchanged ship to shore as well as ship to ship and this lets NLB monitor that buoys are on position and the on board systems are operating correctly, RACON, Light, Battery and solar panels. Remote fixed lights within range of the shore side network of AIS Base Stations can be monitored in the same way.

The benefits of AIS on floating aids to navigation are twofold. Mariners are provided with a more reliable reference point from positioning equipment that is independent of his own shipboard navigation systems and the AtoN authority is provided with a means of monitoring the buoy in terms of its position, movement and the performance of the equipment on the buoy.

DGPS

DGPS site plant information is covered on NLB monitor system but as the DGPS equipment is a fully integrated system and allows comprehensive remote control, the DGPS system is independently monitored using PSTN lines with a PC based display at NLB fully integrated via the internet with the other GLAs' control centres.

The Future

All buoys and minor lights will be monitored. AIS is being developed to provide meteorological data directly to ships. This can include wave height, wind data temperature and visibility. As the power demand required for the instrumentation drops it could be possible to have more of this information available from all locations. Most lighthouse locations do not have broadband links as they are generally old copper circuits to a single location. This bandwidth limitation and power requirements currently restricts the ability to display webcam images.

In the Beginning

The monitoring of lighthouses is not a new concept; amongst the early methods was Northern Lighthouse Board (NLB) using a signal tower at Arbroath to communicate with the keepers at the Bell Rock Lighthouse. When the smaller unmanned lights were installed at the end of the nineteenth century, an Attendant or Observer was appointed by the Board to confirm correct operation. This situation persisted until the "electronic" age when NLB's first attempt at monitoring and remote control was undertaken by the Radio Department at Inchcolm fog signal in the Firth of Forth. The lightkeepers at Inchkeith operated the fog signal and a VHF radio link allowed them to turn on and off the fog signal and generators. Their operation was monitored using a microphone and an open VHF channel back to Inchkeith. Diesel generators were used to charge the fog signal and monitor system batteries - this system operated from the late 1960s until 1974.

For more on the history of Monitoring through the Automation period....More