Search for a rendezvous with lost target at sea

This paper addresses the search problem for lost floating targets on sea surface. Given the expected search region, we analyze spiral search patterns for finding the target. Specifically, we consider two search patterns: outward spiral and inward spiral. The outward spiral pattern is a greedy strategy which initializes from the mean of the search region and expands outwards to cover the entire region. In contrast, the inward spiral pattern first encapsulates the search area and then moves inwards towards the mean. We hypothesize that the inward spiral patterns give guaranteed search outcomes for the lost targets whereas the outward spiral patterns minimize the search time but not necessarily guarantee a successful outcome. We present a theoretical analysis to parametrize the search problem and we validate it using our simulator for realistic sea trials. We experimentally test the effects of varying the initial location of the lost target and the communication radius between the target and the searching agent. Our simulated results confirm our hypothesis and analytical findings.