Interception Strategy Based on Intermittent Information

A penetrator, p , attempts to cross a linear barrier patrolled by a searcher, S . S receives intermittent reports of P 's position, P 1 , P 2 , …, but P knows only that S is somewhere on the barrier. After receiving report P 1 , a time τ can elapse before the next report P 2 may reveal that S may be unable to intercept P even if he received continuous information thereafter. S attempts to select a position S ( P 1 ) that maximizes τ, while P attempts to choose a course α that minimizes τ. If the searcher is faster than the penetrator (speed ratio λ > 1), values of α and S ( P 1 ) that produce maximin τ are deduced. However, maximin τ P is obliged to use a mixed strategy in order to obtain the maximin. If the barrier is finite, contours of constant maximin τ are segments of conic sections. If λ S should modify the maximin τ strategy when P is close to the barrier. An indication is given of the frequency with which reports are needed as P approaches the barrier.