As foreign submarines become increasingly quieter, there is an ever-present need to improve the performance of passive surveillance systems to increase the probability of detection and ability to resolve critical signature differences useful for classification. Passive acoustic surveillance system such as sonobuoys typically employ arrays of hydrophones, configured to discriminate against background ocean noise. Generally speaking, the larger the array, the better noise performance it will have due to more directionality. The problem for sonobuoy based airborne Anti Submarine Warfare (ASW) have a strict volume and weight constraint; presently the US depends strictly on A-size form factor (4 7/8 x 36 ) sonobuoys for a variety of reasons. Therefore, development of small sensor technology is particularly important as the US Navy seeks to remain at the forefront of the international ASW technology race. The issue of space within an A-size buoy presents the opportunity to develop a new, miniaturized acoustic sensor. SeaLandAire proposes to work in conjunction with Undersea Sensor Systems, Inc. (USSI), attacking the development challenges from a sonobuoy systems-engineering perspective. This teaming approach and systems perspective are important non-technical factors to ensure this SBIR funded effort can successfully transition to fleet use.
Benefit: SLAs basic strategy for technical growth is to continually develop and maintain our existing technologies and to expand these technologies into adjacent or related fields of research as the opportunity arises. This allows us to grow in new directions of research while standing firmly on the stable base of the core competencies the company was built upon. The low noise sensor development effort will have a high degree of commercial value. Because the low cost of this sensor will change the way sensors are constructed at a basic level, the applications that could utilize this material technology are virtually limitless. The development of the low cost compact low noise acoustic sensor will have a major impact on a number of programs that are currently in development by the Navy. These systems that are being developed require large numbers of arrays so that they can capitalize on environmental conditions in the ocean. This requires volumetric arrays with high directivity, requiring a high number of sensors. Todays conventional sensor is simply too large to pack that number of them into the limited space that is available. In addition, the noise performance of the sensor needs to be improved. This is a combination of hydrophone and preamplifier improvements. This is as significant as the small size. Because of the number of sensors, the unit must also be low in cost to keep the expendable sonobuoy from becoming too expensive. The acoustic transducer technologies advanced by this SBIR are far reaching within the US Navy sonobuoy programs. The US Navy sonobuoy programs represent one of the largest consumers of acoustic sensors and their associated performance specifications are being pushed for increased capabilities while maintaining an A-sized package. The SLA and USSI team are well positioned within the US NAVYs production and advanced development of underwater sensors programs such that inclusion of the Compact Low Noise Acoustic Sensor into new programs as well as upgrades to existing sensor systems already in production will be a straightforward process. The upgrades will result in improved performance that will continue to push the state of the art in fit form and function of the acoustic sensor and its related subsystems. The primary initial development of this sensor technology is targeted at the military, since that sector is currently one of the most direct users of this type of transducer technology.
Keywords: underwater acoustics, underwater acoustics, Low noise, hydrophone, Sonobuoy, Anti-Submarine Warfare, underwater sensor
