For some time, there have been alarming reports about the likely consequences of some sort of electronic “meltdown” affecting transmissions from navigational satellites – indeed all devices depending on electronic timing devices. Pilot organisations have expressed concern about the possibility of criminals, hackers or even terrorists jamming these signals, using devices which can easily be obtained in some parts of the world.

It has been suggested that these jammers, which are employed by car thieves to disrupt homing devices fitted to expensive cars, have already become widely available in the criminal underworld. A recent police operation in The Netherlands against car thieves, for instance, captured a number of jammers which the criminals had obtained. These jammers are small and portable; even a jammer the size of a cigarette packet could have a range of 30 nautical miles. Signals from satellites, which have a good record of reliability are weak and thus vulnerable.

Members of the General Lighthouse Authorities in the UK and Ireland have for some time been advocating eLoran as a solution to this possible interruption, or indeed any other problems which might affect satellite signals. They have carried out tests afloat which have demonstrated that aboard a modern ship, numerous ship systems will be rendered immediately unavailable in the event of signals being jammed. They have also conducted trials with eLoran in some demanding navigational circumstances and the GLA has suggested that high degrees of navigational accuracy can be obtained by this system, which does not depend upon satellite signals.

The GLA has now installed an eLoran navigation system in the Port of Dover approaches, which gives coverage over the Dover Strait Traffic Separation Scheme and which will provide positional information as a backup to the GPS and other satellite systems in use. Mariners are invited to assess and provide feedback on the system.

The argument for many years, during a period which saw the United States discontinue its Loran system, has been that the availability of duplicate GPS equipment fitted to ships would always ensure that one system would be available to provide positional information regardless of the visibility. Navigators, it was further argued, had become accustomed to GPS, which they believed to be reliable and would be unenthusiastic about alternative systems. There were also cost implications for governments in the provision of transmitting stations, which tended to persuade them to look negatively at such a provision.

Nevertheless, members of the International Association of Lighthouse Authorities (IALA) have persisted in their belief that there was room for a second look at the issue. Moreover, the tests undertaken by the Corporation of Trinity House and its GLA partners have served to emphasise the vulnerability of modern ship systems to the interruption of satellite signals. The opportunity to actually trial the Dover Straits systems, in one of the busiest sea lanes in the world, will hopefully provide some useful feedback that will perhaps encourage further development in eLoran as a backup to any interruption to GPS, should the worst happen.

Author: The Watchkeeper                                   Source: BIMCO