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Underwater Sensor System Autonomous Burial and Operation


OBJECTIVE: Develop innovative approaches to autonomously install, bury, power and communicate from a bottom mounted underwater sensor systems DESCRIPTION: Underwater surveillance in shallow water requires rapidly deployable systems which feature autonomous sensor installation with enhanced survivability against commercial fishing. In addition to rapid deployment, the need exists to bury sensors to enhance survivability against fishing gear that snags/breaks the bottom mounted sensors. Past solutions to deployment of shallow water systems have not been able to solve the need to limit the amount of time a deploying platform is engaged in the deployment process. Current underwater burial systems are not autonomous; they depend on sled-type vehicles towed from a mother ship (See reference 1.). Also, rapid deployment concepts from autonomous platforms have focused on non-burial techniques (see, for example, reference 2.). To date burial solutions require extensive additional time for deploying platforms (mother ship) to complete the installation. An approach is needed to achieve rapid deployment and sensor burial with minimal mother ship involvement. (A desirable by-product of this effort is reduced fuel use by the mother ship.) In general, most autonomous underwater vehicles are either designed for general purpose missions or for special applications, such as hull inspection, not related to the specific task of sensor burial. Preliminary studies show that an operationally suitable package within a pre-determined form shape and deployed from an installing platform in a"fire and forget"mode could resolve many of the current issues. Reference 3 provides information about these studies for illustrative purposes. Offerors are not required to base their approach on these studies. Conceptually, a desirable system would self configure into an autonomous plow vehicle as it descends through the water column when dropped from the installation vessel. Upon landing, the plow would then bury a sensor system in a predetermined configuration (preliminary studies validate the feasibility of a small plow to bury sensors which significantly increases system life in high density fishing areas). After successful completion of the installation, the plow would self bury by water jetting or another method and become the power, processing and reporting node for the system. Requirements of the burial vehicle are that it must be autonomous and carry its own power as well as the payload. This payload includes the sensor system to be deployed as well as the power, electronics and communications system as part of the operational node after deployment. Critical elements of the vehicle include burying a sensor system up to 1 Km long with multiple sensors at depths in the 4 6 inches range (or more) depending on soil type, deploy on bottoms with up to 5 degree slopes and bottom currents up to 1 Kt, have the ability to negotiate obstacles (e.g., rocks/cables), navigate and operate over various soil conditions and bottom types, be able to make one 90 degree turn during the installation in addition to maneuvering if needed for obstacle avoidance. The government envisions the sensor system cable diameter to be up to 75mm and to contain up to one hundred 2.5 cm diameter passive acoustic sensors spaced along its length. The deploying vehicle must be packaged to minimize space in transit. PHASE I: Develop a concept for an autonomous vehicle that will install and bury an underwater sensor system to protect against threats and hazards due to fishing activity. Perform analytical analyses on critical elements of the installation and burial system to characterize the physical limits to the system as input to the design. Provide convincing support for the feasibility of the proposed conceptual design, integration techniques, and installation method. PHASE II: Develop a prototype burial system and demonstrate its ability to install the sensor system while preserving the acoustic, electrical and mechanical functionality needed for the overall system application. Full functionality is not required, only demonstration of the burial aspect; other system functions can be shown to be accommodated by engineering drawings. Propulsion of the device can be conducted by surrogate means as long as the engineering drawings accommodate space for the power generation and fit within the total system weight / volume constraints. Full"blooming"of the system from stored to deployed state can be demonstrated by design drawings; the at sea demonstration does not need to feature starting from the stored (compact) state. Detailed design drawings are required. PHASE III: Transition the technology to undersea surveillance systems to be situated in littoral environments where bottom fishing activity is present. Possible environments are in overseas locations to be specified. This deployment and burial concept can be applied to all sensor systems that could fit within the packaging parameters of the vehicle, providing a long term shallow water surveillance capability currently not available. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The oil and gas, commercial telecommunications industries and scientific communities that operate in the littorals all have similar issues with survivability of distributed infrastructure components. Large companies often rely on smaller niche robotic developers to solve their deployment and burial challenges, so extension of the cable burying technology developed under this STTR has ready dual-use applications. REFERENCES: 1. Messina, Frank D."Advances in Undersea Cable Burying Technology for the 21st Century." 2. ISE International Submarine Engineering. Theseus. 3. [Public release information being prepared on SPAWAR Systems Command Pacific Autonomous Burial Vehicle Engineering Study and patents pending]
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