Abstract :
While there are some 250 000 civil aircraft in the world, only about 500 of them are in transoceanic service and therefore prime candidates for the systems described in this special issue. The rest mainly depend on short-range systems treated elsewhere. However, there are 25 000 ocean-going merchant ships. The article discusses some nontechnical factors that influence the choice of systems for these markets, including the institutional, the "CNI" factor, the marketplace, cost, redundancy, and vulnerability.
