Barrier Coverage

Suppose sensors are deployed randomly in a long thin strip, and suppose each sensor can detect objects within a fixed distance. We say that the sensors achieve barrier coverage if there is no path across the strip that a small object can follow that avoids detection by the sensors. We give fairly precise results on the probability that barrier coverage is achieved as a function of the range of the sensors, the height and length of the strip, and the number of sensors deployed. In particular, we show that the most likely obstruction — a rectangular region crossing the strip which is devoid of sensors — does not in general dominate the probability of failure of barrier coverage.