Review of Autonomous Undersea Vehicle (AUV) Developments 
reusable UUVs; launch and recovery equipment, including a winch and drogues; and shipboard 
control, processing, and monitoring equipment. Each UUV is slightly shorter than an Mk 48 
torpedo and is launched and recovered via a standard SSN 688-Class torpedo tube. The UUVs 
contain highly accurate sonar systems that can pinpoint and classify minelike objects. Batteries 
provide the power needed to propel the vehicle during its sortie and operate the on-board 
electronic systems. Vehicle status, position, and sonar data are continuously relayed back to 
the host SSN via a fiber-optic cable, thereby allowing continuous monitoring of the vehicle 
during sortie operations and real-time analysis of data to the SSN from potentially mined waters. 
The UUV is loaded backward into the SSN 688 torpedo tube. Once ship conditions are correct, 
the UUV backs out of the tube under its own power. Outside the SSN (but still coupled to it via 
a steel cable and drogue assembly), it is towed to its mission area. The UUV then releases 
from the drogue; fiber-optic cable begins to pay out from both the drogue and vehicle; and the 
UUV independently transits and conducts its mission. Should the fiber-optic cable break, the 
UUV is programmed to autonomously return to a pre-set rendezvous point for recovery by the 
SSN. When the mission is finished, the UUV will rendezvous and mate with the drogue. A 
winch located in the SSN torpedo room will then pull the complete combination back into the 
torpedo tube. A trained Navy cadre will be responsible for the operation and maintenance of the 
NMRS when deployed. Cadre members are responsible to prepare and conduct UUV sorties; 
monitor vehicle status during transit and operation; replenish the UUVs post-sortie; and compile 
analysis of mission data. 
The NMRS Prototype (figure 4) commenced its at-sea test 
period in March 1998 at the Dabob Bay Test Range in 
Keyport, Washington. A detailed series of tests assessing 
vehicle and drogue_ stability, hydrodynamic control, 
navigation, and sensor performance was performed. In 
June 1998, the Navy successfully demonstrated its NMRS 
during the JCM ACTD held under NATO auspices off 
Stephenville, Newfoundland. NMRS was part of a large- 
scale amphibious warfare exercise designed to showcase 
emerging shallow-water mine warfare technologies. Figure 4. NMRS Prototype 
During the ACTD demonstration, the NMRS conducted five mine reconnaissance and survey 
sorties both in deep-water areas, with depths greater than 200 feet, and in shallow water (less 
than 200 feet) with varying bottom types. Since NMRS is designed to operate from a submarine 
torpedo tube, new procedures were developed to support surface launch and recovery from the 
research vessel. Navy Cadre members constructed all sortie plans using available information 
provided about the area and anticipated threat. Ultimately, all tasks were successfully 
completed, and the NMRS logged more than ten hours of operational search time. Suspected 
minelike objects were reported using standard mine warfare messages after detailed 
reconstruction and review of sonar data from the sorties. 
20 
