Where to Dip? Search Pattern for an Antisubmarine Helicopter Using a Dipping Sensor

Abstract

Antisubmarine warfare (ASW) had been an important topic for military operations research (MOR) modelers and analysts during World War II and the Cold War. It became, however, somewhat out of vogue with the collapse of the Soviet Union and the subsequent reduction of the threat of submarine-related conflicts. In recent years, threats of such engagement have increased, in particular in the South China Sea. The re-emerging interest in this type of warfare, combined with new technologies and resulting tactics, pose a renewed challenge for MOR researchers. e study effective ways to operate a helicopter, equipped with dipping sonar (a dipper) in ASW missions. In particular, we examine the dipping pattern and frequency. A high rate of dipping is desirable as search effectiveness degrades in time as the search area expands. However, dipping too frequently results in overlap with previous dips, which may be wasteful. For a cookie-cutter sensor and a known constant submarine velocity, we prove that disjoint dips are optimal and generate the corresponding optimal dipping pattern. We analyze the effect of factors, such as helicopter speed, submarine speed, sensor detection radius, and travel time to the point of detection, on the optimal dipping pattern. We show that temporal parameters (submarine velocity and helicopter arrival time to the datum) are most critical. We also show that the no-overlap result is not always true; when the submarine's velocity is only known with probability, the optimal dipping frequency may include overlaps.