*2.9.1. Prospective of concept of operations*

combustion engines or other available energy sources is found in Jane's Underwater Technol‐ ogy Information. Important UUV power system performance metrics consist of energy and power, specific energy and power, usable state of charge, voltage response under load, calendar life and charge acceptance specifically, power and energy density and physical volume are critical to UUV system design. **Figure 3** [24] shows the specific power and energy

Based on current technology development of battery systems, high-performance battery is the most favorable choice for the autonomous vehicles based on performance, availability and cost-effectiveness. With battery applications, to facilitate the addition of battery packs to the vehicle, the hull shape should be redesigned to be longer or wider. Such hull reshaping reduces the overall vehicle drag coefficient and increases energy to UUV's propulsion power. As UUV energy systems are characterized by specific energy or power density per unit volume or weight, adding additional energy to the system increases the vehicle length [23]. When the battery packs are added, the midsection (*D*) must be longer (*L*) in order to house additional battery packs. This changes the aspect ratio, and increases the vehicle drag coefficient. Increased vehicle drag requires more propulsion power, which is a portion of added energy. The sensitivity to added battery packs is compensated for by changing the axial drag coeffi‐

Based on the Ragone Chart characteristics [23], the preferred long-term approach to using hydrogen is the fuel cell. Fuel cells use a process that is essentially the reverse of electrolysis to combine hydrogen and oxygen in the presence of a catalyst to generate electricity. Fuel cells are much more efficient than ICEs often topping 70% [24, 25]. The main problem with fuel cells is the cost, and the other primary issue with fuel cells is durability. Both of these renewable fuels have lower heating values (Btu/gallon) than their counterpart gasoline and diesel fuel, resulting in higher fuel consumption when measured on a volume basis. Diesel engine offer

cients as and other conditions, including hotel loads, are unchanged.

properties of major UUV energy sources.

136 Autonomous Vehicle

**Figure 3.** Energy source characteristics, Ragone Chart [24].

The main concept of MCM operations using UUV systems is to reduce incoming threats for the naval fleet with the employment of a robust, highly autonomous vehicle unit which is capable of operation engagement and execution of neutralization procedures. Neutralization procedures include either moving the mine out of the original place, precise delivery of the charged device to a desired location or the acquirement of projectiles to blast previously localized, in volume, drift, floating and bottom mines in deep and shallow water zones [15, 16].

The main body of the new MCM UUV has fully trained AI expert systems with MCM data bases to implement mission movement, in addition to vehicle and contingency operational management. The MCM UUV system has expandable small UUV sensor/neutralizers with a formed charge, and it is able to acquire projectile reaching and explode designated mines. Before it begins actual disposal activities, the control module of UUV unit requests a confir‐ mation of mine identification to the mother ship via acoustic and RF communication links [8].

In the envisioned concept of operations, a UUV unit uses its high capacity communication links to get prior mine target information from the MCM operation center at the mother ship which is located more than 50 miles standoff distance [6] at high sea as shown in **Figure 4**. The vehicle then initiates an adaptive engagement plan autonomously along its trajectory with the available information from the navigation sensors. While compensating for winds, waves and currents along the disposal range, it will try to navigate accurately to the designated mine target. All the way to the designated mine position, the launched disposal device maintains the targets in the field of the imaging sonar. After neutralizing the designated mine, the UUV unit performs a neutralization damage assessment, and reports that the mission has been accomplished [18].

**Figure 4.** Concept of MCM UUV system operations.
