The proposed development on the Loop Head peninsula is for the construction of a high mast supported by stay-wires. It includes ancillary facilities and a caretaker's house.
The mast would be used as a radio transmitter and would form part of the radio navigation system known as Loran C, used primarily for marine navigation.
It was developed primarily for the United States Department of Defence but has been widely availed of by civilian users in the areas covered by its signals.
If constructed it will form part of the system serving the north Atlantic and north-western Europe. The system was formerly funded by the US Coast Guard as an aid to US naval operations in Europe, but this funding was withdrawn from 1992 because of a move by the US to a satellite system.
It appeared, according to yesterday's judgment, that the view was taken in a number of European countries, including Ireland, that the Loran system should continue to operate in order to avoid a total dependence on satellite systems.
The court was not concerned with the question of whether the Loran system was, or might be, obsolescent, which was suggested by the two farmers challenging the development. That suggestion was rejected by the commissioners.
It was acknowledged by all the parties to the dispute that, when An Bord Pleanala made its decision on the development, the Government's policy was to support the maintenance of the Loran C system, not simply because of its intrinsic merits but also because the view was taken that Ireland was bound to adopt that position in the light of the Oslo Agreement concerning the establishment and operation of the system. It was not disputed that such a system was an important aid to safety.