A quantum photonic imaging device used in an underwater vehicle for stealthy detection of underwater objects includes a photon generating module that generates an entangled pair of photons that includes a signal photon and an ancilla photon, wherein the ancilla photon is retained within the device; a transmitter that transmits the signal photon towards a region of space for detecting an underwater object; a receiver that detects an incoming photon to the device; and a correlation module that distinguishes the signal photon that is reflected back to the receiver due to a presence of the object from environmental noise photons, wherein the distinguishing includes determining an entanglement correlation of the detected photon with the ancilla photon, and wherein a presence of the entanglement correlation between the detected photon and the ancilla photon indicates that the detected photon is the signal photon reflected back from the object.

An apparatus for close visual inspection of subsea pipelines comprises a housing with a chamber that has an open side. The open side is adapted to be placed in sealing engagement against the pipeline. The chamber is flooded with clear water to improve the visual view. It is also described an apparatus for identification of a plume exiting from a leak The apparatus comprises a housing defining a chamber with a water permeable side that is adapted to face downward during use, and thereby being exposed to the exiting substance. A gas pressurizing device for creates a gas/water interface within the housing. An imaging device arranged above the water surface is adapted to image the water surface and detect id the water surface is being disturbed by the plume.

An apparatus for close visual inspection of subsea pipelines comprises a housing with a chamber that has an open side. The open side is adapted to be placed in sealing engagement against the pipeline. The chamber is flooded with clear water to improve the visual view. It is also described an apparatus for identification of a plume exiting from a leak The apparatus comprises a housing defining a chamber with a water permeable side that is adapted to face downward during use, and thereby being exposed to the exiting substance. A gas pressurizing device for creates a gas/water interface within the housing. An imaging device arranged above the water surface is adapted to image the water surface and detect id the water surface is being disturbed by the plume.

A sensor suspension system for use in an underwater environment comprises a sensor (e.g., vector sensor) and a framework comprising a plurality of support structures, and a plurality of compliant devices that suspend the sensor within an inner volume of the framework. The plurality of compliant devices facilitate a symmetrical sensing response of the sensor in three degrees of freedom when deployed in the underwater environment. The framework is moveable from a collapsed position to an expanded position. A plurality of sensor suspension systems can be tethered together into a sensor array by a deployment control system operable to release a buoyant device, tethered to the sensor suspension systems, that vertically positions the plurality of sensor suspension systems into the sensor array. The buoyant device can cause each framework to expand via pulling force through the tethers upon release of the buoyant device.

A sensor suspension system for use in an underwater environment comprises a sensor (e.g., vector sensor) and a framework comprising a plurality of support structures, and a plurality of compliant devices that suspend the sensor within an inner volume of the framework. The plurality of compliant devices facilitate a symmetrical sensing response of the sensor in three degrees of freedom when deployed in the underwater environment. The framework is moveable from a collapsed position to an expanded position. A plurality of sensor suspension systems can be tethered together into a sensor array by a deployment control system operable to release a buoyant device, tethered to the sensor suspension systems, that vertically positions the plurality of sensor suspension systems into the sensor array. The buoyant device can cause each framework to expand via pulling force through the tethers upon release of the buoyant device.

An underwater work system of the present disclosure acquires a relative position of an underwater vehicle relative to a surface ship at the start of searching work, the relative position being measured based on a sound wave transmitted from a wave transmitter. The underwater work system calculates a position of the underwater vehicle based on the acquired relative position. When a measurement error region whose center corresponds to the calculated position of the underwater vehicle and an expected laid region of a pipeline extending in a predetermined direction overlap each other, the underwater work system moves the underwater vehicle to such a position that the measurement error region and the expected laid region do not overlap each other, and then, makes the underwater vehicle perform crossing detection in which the underwater vehicle detects the presence or absence of the pipeline while crossing the expected laid region.

A system for inspecting flexible pipelines comprises a data analyzer, a data collector and an ultrasonic transducer. Further, the ultrasonic transducer is adapted to propagate shear wave into the annulus of the flexible pipeline. The data collector further comprises a data store and a communicator. Further, the system is capable of differentiating flooding and non-flooding condition of the annulus of the flexible pipeline which is subjected to high pressure. Using the system, an indicator of a flooded or non-flooded condition within the flexible pipeline may be calculated using transmitted and detected reflective waves or the lack of detected reflective waves.

A system for inspecting flexible pipelines comprises a data analyzer, a data collector and an ultrasonic transducer. Further, the ultrasonic transducer is adapted to propagate shear wave into the annulus of the flexible pipeline. The data collector further comprises a data store and a communicator. Further, the system is capable of differentiating flooding and non-flooding condition of the annulus of the flexible pipeline which is subjected to high pressure. Using the system, an indicator of a flooded or non-flooded condition within the flexible pipeline may be calculated using transmitted and detected reflective waves or the lack of detected reflective waves.

A working method using an AUV includes a step of working on a work object with a work device included in the AUV while causing the AUV to sail along the work object, a step of dropping and sinking a transponder to the bottom of water, a step of causing the AUV to sail toward a return destination, and a step of resuming work on the work object by causing the AUV to sail from a return destination to the vicinity of a work suspended position, at which work on the work object is suspended, based on information obtained by acoustic positioning using the transponder that is sunk to the bottom of water.

A working method using an AUV includes a step of working on a work object with a work device included in the AUV while causing the AUV to sail along the work object, a step of dropping and sinking a transponder to the bottom of water, a step of causing the AUV to sail toward a return destination, and a step of resuming work on the work object by causing the AUV to sail from a return destination to the vicinity of a work suspended position, at which work on the work object is suspended, based on information obtained by acoustic positioning using the transponder that is sunk to the bottom of water.