Communications

Satellite systems


Malcolm Latarche
Malcolm Latarche
ShipInsight

10 July 2019

Satellite systems

Satellite systems comprise two main components, the antenna which is installed above the bridge and the electronics and displays below. With most L-Band systems, the cost of the system and antenna will fall to the ship operator and the equipment will be owned outright. When opting for VSAT systems, there is a choice with many shipowners preferring to lease the equipment rather than purchase it themselves. Aside from the lower capital outlay, a lease contract will ensure that advances in technology do not render expensive equipment obsolete as the lessor will usually provide upgrades as necessary.

The under deck components of a satellite system are normally nothing more than an imposing box of electronics to which multiple components can be attached. If the system has been installed solely for GMDSS purposes, the only connected devices will be the GMDSS station and any remote displays.

Where the satellite system has been installed for reasons other than GMDSS, the attached devices can be many and various. In many ships the satellite communication unit will be connected to a local area network (LAN) to which will also be connected several PCs, communication devices such as telephones, faxes and possible wireless hubs allowing use of mobile phones, PDAs and tablets. Updating of electronic navigation charts is already common on many ships and as the rollout of mandatory ECDIS accelerates it will become even more so.

Another use that is growing is the monitoring of engines and other equipment on board. Sensors on engines recording temperature, pressure and multiple other parameters using a proprietary control unit can have the data they recorded compiled and sent via the satellite to the machinery supplier for constant diagnostics and to satisfy computer-based maintenance programmes.

Remote monitoring and reporting need not be confined to machinery, it is possible to link an output from a ship’s VDR to the communication system and so supply the shore office with information for incident investigation or even real-time monitoring in emergencies.

Such centres are to be found more and more often in the head offices of major ship operators and in the largest are also duplicated in different locations around the globe.

On certain research and seismic vessels, the data from instruments can also be compiled and despatched automatically. Despite satellite equipment having now been installed on ships for around four decades, it has to be said that the opportunities and benefits that it offers are only just beginning to be explored. However, with the world fleet growing rapidly in numbers and data usage expanding even faster, the limits of even the increased bandwidth allowed by expansion of VSAT into the Ku and Ka bands could be reached in the not too distant future. Some industry observers believe that within less than a decade, satellite usage will have increased by a factor of five even without new uses for data transmission becoming available.