Optimal Survivor Search with Multiple States

The optimal survivor search problem is to maximize the probability of finding a moving target alive. The target may be a person missing at sea or lost in a wilderness area. In a multistate target problem, the target is moving and changing states stochastically. Each state may imply different motion and detectability assumptions. We find necessary and sufficient conditions for optimal detection plans for multistate targets. Using these conditions, we extend the algoritnms of Brown and Stone for finding optimal detection search plans for moving targets to multistate target problems, and show that the optimal survivor search problem may be solved as a special case of the multistate target problem.