Review of Autonomous Undersea Vehicle (AUV) Developments 
"weathervanes" into the current but remains aimed toward the target object. If the standoff 
distance is selected to be equal to the distance between the imaging camera (at the front of the 
vehicle) and the Doppler sonar (which is aft of the camera and is used to determine the position 
of the vehicle), the camera stays over the target. This is a completely autonomous routine that 
is range insensitive and requires only one supervisory command to send the vehicle to a target. 
As the AUSS system became operational and more dependable, a number of other innovative 
supervisory control system advances were invented to simplify the supervision of the undersea 
vehicle operations. Among these was target marking, wherein the location of a target object in 
the vehicle's onboard navigation coordinate system is automatically calculated when a cursor is 
placed over its image. Target marking was applied to Side Looking Sonar (SLS), Forward 
Looking Sonar (FLS), and Cooled Charged Coupled Device (CCCD) imaging portions of the 
AUSS mission. 
The synergy of hover at a radius and target marking made a significant contribution to the 
efficiency with which the system could view objects (targets) on the bottom. Each step in the 
target marking/hover at a radius sequence brings the AUSS closer to the objective target using 
successively shorter range, higher resolution sensing. An SLS target mark is used to determine 
a position for the vehicle to go to, hover at, and obtain an updated target mark with the FLS. 
FLS target mark is used to determine a position for the vehicle to go to, hover at, and obtain the 
first CCCD image. Finally, the cursor is moved about on the CCCD screen to mark positions for 
the vehicle to go to and obtain CD image coverage of the target area. 
Sixty-five hours of bottom time were logged during eight dives between 5 April and 24 June 
1992. These eight dives produced some compelling results. During the showcase, SLS search 
rates were as high as 1.5 sq-nmi/hr. Contact evaluations (the process by which targets are 
found and imaged with CCD) typically took between 10 and 15 minutes. This process includes 
the time between the operator's identification of a potential target on SLS and the time when the 
vehicle was once again searching with SLS. The AUSS demonstrated fully operational dives 
between 2500 and 12,000 feet, depth-independent supervisory controlled search tactics, and 
excellent compression-enhanced acoustic link performance to 12,000 feet. 
During a single dive at 4000 feet, consistent SLS search was conducted at speeds between 4.5 
and 5 knots with a swath of 2000 feet. The area searched during the dive was 7.5 sq-nmi, and 
the time to conduct SLS search and contact evaluations was 8.5 hours. This demonstrated an 
SLS search rate better than 1.5 sq-nmi/hr and an overall search rate (including contact 
evaluations) of 0.9 sq-nmi/hr. 
In another 4000-foot dive, over 2.5 sq-nmi were searched, including several lengthy contact 
evaluations and three photomosaics (series of overlapped CCD images taken while the vehicle 
performed a small search pattern over a target area). The contact evaluations included a 55- 
foot yacht and a Korean War vintage Skyraider night fighter aircraft that were both discovered 
and position pinpointed during the dive. An autonomous 5-nmi transit was also performed 
during the 14 hours the AUSS vehicle was submerged. 
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