Defining surf zone crawler search strategies for minefield reconnaissance

Abstract

The Concept Assessment and Development (CA&D) Team in the ONR's VSW/SZ MCM Advanced Technology Development Program is developing simulation analysis tools to support concept development and system design tradeoffs. The CA&D Team has made considerable progress defining search and area coverage tactics for surf zone (SZ) crawlers performing search, classify, and map (SCM) reconnaissance functions. This paper summarizes the state of current knowledge on crawler utilization and search tactics, based on a number of simulation studies evaluating single and multiple crawlers performing random and pattern (or complete) search strategies. The paper offers recommendations on parametric definition of these strategies, and discusses real-world situations in which random search strategies outperform pattern search strategies. In the studies described, the random search strategy is defined by leg length and course change, as well as by the search area boundary interaction algorithm and the obstacle avoidance method. Pattern searches are defined by the type of search (e.g., lawnmower or spiral), the cycle/sub-cycle definition (waypoints or number, length, and orientation of legs), and the obstacle avoidance method. Pattern search strategies guarantee complete area coverage under ideal conditions, but they are non-adaptive. The pattern search obstacle avoidance objective is to expeditiously resume the search pattern with minimum coverage holidays. Since the studies focused primarily on search strategy definition, the results are presented mainly in terms of time to cover a given area to a threshold level (or percentage), and the probability of complete coverage. The presentation also discusses some additional study results concerning detection/classification sensor requirements and minefield counter-countermeasure vulnerability.