An integrated marine radar system

Fault records on a particular marine navigational radar are analysed to determine the probability of successful performance over a given interval. This indicates that certain units are much less prone to failure than others. The duplication of equipment to give greater reliability is examined, and it is shown that from the reliability point of view it is more efficient to duplicate only the least reliable units, and to provide facilities so that any combination of the available duplicates may be switched into use in the complete system. A comparison is drawn between two installations using the same units, one consisting of two complete but independent radar sets, the other providing higher reliability by the use of fewer units with switching facilities. Several switching arrangements are in seagoing use, and examples of these are given, showing that in addition to increased reliability they provide operational facilities not available on a single equipment. Some of the problems overcome in the design are discussed, particularly the interaction of human engineering and switch mechanisms in a multiple switching operation, and the influence of these factors on the final design. S.S. Canberra carries the most complex equipment of this type to date, and the paper concludes with an illustrated description of the installation.