Naval Surface Warfare Center (NSWC) - Panama City Division

An air-delivered submersible vehicle system has a monocoque-construction shell made from a fiber-reinforced plastic material selected from the group consisting of thermoplastics and thermoset plastics. The shell is equipped with a wing kit so that it can be deployed from an aircraft and fly through the air to a destination at a surface of a body of water. The shell is further equipped as a submersible vehicle so that it can be propelled through the water once it has reached its water destination.

A combination pressure relief valve system and undersea vehicle vents pressurized gas from lithium batteries to ambient. An undersea vehicle having an interior has a pair of hollow pylons each having a passageway fluidly communicating with the interior. A pressure relief valve is mounted on each pylon, and each pressure relief valve has a body portion having an inner bore fluidly communicating with a passageway. An elongate valve plug in the body portion is interposed between each passageway and ambient and the valve plug has a lateral bore and a circumferentially disposed O-ring. A nose portion is secured to the body portion, and the nose portion has a pair of laterally aligned bores aligned with the lateral bore of the elongate valve plug. A wire extends through the laterally aligned bores and lateral bore. The O-ring and wire retain the valve plug interposed between a passageway and ambient.

A method and apparatus for eliminating aspect dependence of images generated by a radiative scanner such as a radar, sonar, or the like. Echoes from the scanner are received back and detected at a known and preselected number of aspects. The echo received at each aspect is multiplied by the transform of the point spread function of each of the other preselected aspects. In this manner, the frequency domain version of each echo is multiplied by the frequency domain point spread function of all of the preselected aspects, and the ultimate processed echo will be aspect independent.

A portable, diver-operated cryogenic freezing unit cleans surfaces underwater. A housing has a first chamber that contains cryogenic liquid, such as liquid nitrogen, and a second chamber is disposed adjacent to an end portion that fits about contaminating matter on a surface underwater. A valve vents cryogenic liquid from the first chamber to expand as gas in the second chamber. The vented cryogenic liquid and gas freeze a slug of water and the contaminating matter on the surface within the end portion. The housing is bent, twisted or otherwise displaced to break or pry-away and remove the frozen slug of water and contaminating matter from the surface to thereby clean it. A method of cleaning a surface underwater using the cryogenic freezing unit is described.

Vehicle attitude is estimated relative to a ground surface over which the vehicle is traveling. An actual image of the ground surface over which the vehicle is traveling is compared with stored or predicted model images of the ground surface. The model images have corresponding known vehicle attitudes associated therewith. For one of the model images that most closely matches the actual image, the known vehicle attitude associated therewith is an estimate of an actual vehicle attitude relative to the ground surface over which the vehicle is traveling.

A method of focusing fully-coherent circular synthetic aperture sonar (CSAS) imagery is provided. A k-space representation of the CSAS image is generated using the two dimensional Fast-Fourier Transform (FFT). Sub-aperture images are generated by windowing the k-space representation and applying the two dimensional inverse FFT to the windowed spectrum. All adjacent complex sub-aperture images are correlated, the correlation peaks are detected and the relative shifts in X and Y as a function of look-angle are recorded. The relative shifts between adjacent sub-apertures are integrated and the means are subtracted to find the absolute shift as a function of look-angle. A motion-solution is calculated by exploiting the relationship between apparent scene shift and actual vehicle sway. The motion estimation is used to generate a phase-correction matrix that is multiplied by the k-space representation of the fully-coherent image.

Methods and systems detect changes occurring over time between synthetic aperture sonar (SAS) images. A processor performs coarse navigational alignment, fine-scale co-registration and local co-registration between current image data and historical image data. Local co-registration includes obtaining correlation peaks for large neighborhood non-overlapping patches. Relative patch translations are estimated and parameterized into error vectors. Interpolation functions formed from the vectors re-map the current image onto the same grid as the historical image and the complex correlation coefficient between images is calculated. The resulting interferogram is decomposed into surge and sway functions used to define the argument of a phase function, which is multiplied by the current image to remove the effects of surge and sway on the interferogram. Based on the aforementioned computations, a canonical correlation analysis is performed to detect scene changes between the historical and new SAS images.

A method and system for selecting a threshold for use in detecting anomalous objects, or targets, in images with a tractable false alarm rate. A method includes steps of identifying a number of peak values from a plurality of values; calculating an average peak value from the identified peak values derived in the previous step; and calculating the threshold according to the average peak value; the number of identified peak values; and a predetermined number of false alarms. In this manner, object classifications are accurate; the number of false alarms is reduced; and redundant classifications are minimized for each image.

A method and system are provided for automatically retrieving information associated with vehicles that must sequentially pass an entrance to a secure site. Prior to the entrance to the secure site, a plurality of vehicles can be aligned in a queue having a front end located at the secure site's entrance. When a vehicle enters the queue, identifying indicia on the vehicle's license tag is automatically transmitted to one or more remotely-located databases in order to retrieve information associated with the license tag. When the vehicle reaches the front of the queue, the information so-retrieved is automatically made available in a human recognizable format to security personnel at the secure site's entrance.

An autonomous craft controller system for automated control of operation of a landing craft air-cushioned vehicle includes a command processor, a bow thruster controller, a prop pitch controller, and a rudder controller. The command processor receives and processes multiple inputs relating to vehicle heading, location and velocity and, in response thereto, produces multiple outputs relating to vehicle acceleration and vehicle heading, velocity and position error. The bow thruster controller receives and processes as inputs some of the multiple outputs from the command processor and, in response thereto, produces a bow thruster command output. The prop pitch controller receives and processes as inputs some of the multiple outputs from the command processor and, in response thereto, produces port and starboard prop pitch command outputs. The rudder controller receives and processes as inputs some of the outputs from the command processor and outputs from the prop pitch controller and, in response thereto, produces a rudder command output.