A Priori Planning of ASW Operations: Providing a Robust Mission Advice

New underwater sensors, such as the Low-Frequency Active-Passive Sonar (LFAPS) and the Helicopter Long-Range Sonar (HELRAS), have larger detection ranges than existing sonar systems. Effective and efficient deployment of these sensors in Anti-Submarine Warfare (ASW) operations requires decision support. TNO has performed research on both ‘a priori’ and ‘in situ’ planning of such operations, where ‘a priori’ is about planning at the tactical level, both long (months) and shortly (weeks, days) before a mission, and ‘in situ’ is about sensor performance and sensor settings during a mission. A priori planning is used for planning specific missions. This means that the area of operations and the expected threat are roughly known. Still, several uncertainties remain, such as the actual environmental conditions (which hugely affect the detection ranges) and enemy behaviour. These uncertainties may influence the operational effectiveness, e.g. the timely detection of enemy submarines. Hence, they must be taken into account when providing decision support for planning the ASW operation. The resulting algorithms of the a priori research have been incorporated in a demonstrator called APPAD (A Priori Planning Aid Demonstrator). Much attention was paid to the robustness of the advice on the best way to deploy the participating platforms. A robust tactic should perform reasonably well even if the uncertain parameters (such as the detection ranges) change during the actual mission. A robust mission advice provides the ASW commander with a set of alternative tactics that enable a robust performance. This allows the ASW commander to select the best solution, based on his experience and his knowledge of the actual tactical situation.