The Earth's surface has more water than land, and the monitoring of naval ships and armadas is an important function in global warfare. Ocean surveillance systems have commercial applications as well, and both will be discussed in this chapter. We begin by examining military applications.
This hypothetical problem, inspired in part by Tom Clancy's Red Storm Rising, is the constant observation of the North Atlantic Ocean, although another area could equally well be considered. The general requirements are that vessels as small as destroyer escorts would be detectable, and the vessels should be observed in a manner that is timely with respect to their speed and maneuverability. Only surface vessels will be considered; submarines are a very different matter. Continuity, detectability, and coverage are the issues.
Several possible approaches to this include a geosynchronous satellite that can sit in position and monitor the entire area in a single frame, the same satellite that covers the area in several frames, and a lower satellite that passes over the area periodically. The airplane is not an option (as it was briefly in the MX problem).
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