No abstract

The Department of the Navy 2021 Unmanned Campaign Framework has identified a need for increased capability in long-term autonomous maritime systems. In the context of this research, long-term autonomy is defined as the capabilities of self-governance, situational awareness, and operation independent of human interaction over a prolonged period. DARPA’s Anti-Submarine Warfare Continuous Trail Unmanned Vessel (ACTUV) program, now the U.S. Navy’s Sea Hunter program, among others, showcases the Navy’s commitment to develop and explore unmanned autonomous maritime systems. One of the challenges for development of these unmanned systems lies in the ship design process.  Traditional ship design methods assume crewed operations when sizing the systems, generating layouts, and considering operational requirements.  Existing unmanned maritime systems are often retrofitted to be unmanned rather than being uniquely designed for their purpose. Even in cases where autonomous systems are designed from scratch, these systems are fundamentally limited by technologies developed for traditional vessels. This can result in suboptimal solutions and missed opportunities. In particular, a lack of focus on reliability and endurance in both technology development and early in the design process results in significant impacts to unmanned systems. Reliability is often measured using mean time between failures. Given that maintenance is traditionally carried out frequently, reliability is not often a limiter for mission success, as the crew can handle non-critical failures. This assumption becomes invalid in the sphere of autonomous ship design, where theater maintenance is not feasible. For example, in a test voyage from SanDiego to PearlHarbor, Sea Hunter relied on crew on a support vessel to resolve several mechanical issues which arose in its journey. This suggests a possible technology gap in the reliability of subsystems key to autonomous maritime systems. Entwined with reliability is endurance. Endurance refers to how long the vessel can stay out at sea, a critical factor for many autonomous missions. Additional aspects of traditional ship design will need to be altered, including but not limited to the following: human support systems, human interfaces, and general structural design.The authors propose a set of modifications to the traditional ship design process to support the design of autonomous ships starting from concept design through full contract design.  Design disciplines specifically tailored to unmanned system design will be incorporated into the design process.  A technology impact forecasting (TIF) study will be conducted to determine key areas of research needed to support future unmanned systems.  This approach results in system performance metrics needed to meet requirements and quantifies the deficits or surpluses by comparison to a baseline vehicle and mission. The baseline mission for this analysis will be a security anti-submarine warfare activity similar to the ACTUV program, with an initial endurance goal of 90days. The TIF analysis of this baseline mission will quantify gaps in performance metrics and will offer a guideline for where further research and investment are required to enable the vision of long-term autonomous maritime systems.