Most production sonobuoys are packaged in air-deployable, A-sized housings and are used as free-floating passive acoustic sensors. They provide good detection capability in a wide range of noise and threat conditions, but there are noise environments where improved detection capability is desirable. To provide the improved detection, new designs are needed that take advantage of velocity or vector sensor elements, line arrays, and enhanced processing to provide the capability of array gains of at least 24 dB for a variety of noise and threat environments. This new sonobuoy should have the capability to operate in both shallow and deep water. Due to the high array gain that is required, a limited bandwidth of 500 to 1000 Hz will be considered. SeaLandAire proposes a line array of compass-corrected vector sensor elements as a baseline design to achieve a gain of 24 dB. The baseline design uses an existing miniature DIFAR hydrophone design for the sensing elements. Trade studies will be conducted in Phase I to evolve the baseline design to optimize performance. Beamforming will play a pivotal role in the trade studies. Trade parameters include; cost, packaging volume, number of elements, reliability, array length, power, deployment, array angle, etc.
Benefit: A sonobuoy that could provide large array gain (>24db required) would be an appealing complement to the US Navys airborne Anti-Submarine Warfare (ASW) acoustic capability. As mentioned in the solicitation, the Navy has a need for an A size sonobuoy that can provide large array gain to supplement existing capabilities. The Navy is clearly the primary customer for this technology. However, some of the technology may be able to spin of into other markets. Acoustic sensors are used for marine mammal monitoring, homeland defense, drug interdiction and other acoustic sensing applications. Small vector sensors and sensor systems with high sensitivity may appeal to these markets if the price is relatively low. It has been our experience that unless a funding route is started years in advance, the program will languish due to a lack of funding. Therefore, we will pursue not only the technical, but also the funding route throughout the development process. We will do this initially through the TPOC but will also seek other potential sponsors. The Navy has very good support programs to help move Phase I into II SBIRs and on to commercialization. SeaLandAire has attend the TAP program for previous SBIRs and found that to be effective at initiating contact with potential sponsors. Consequently we plan to continue to participate in the TAP program. Development of this technology into a qualified production sonobuoy can be expected to take several years and several million dollars. It is anticipated that future sales of this buoy would be in the hundreds or low thousands per year, versus tens of thousands for current production sonobuoys. Based on past experience, the need for this sonobuoy in limited numbers does and will exist for years to come.
Keywords: Sonobuoy, Sonobuoy, velocity sensor, acoustic sensor, vector sensor, beamforming, hydrophone, Horizontal Line Array
