Mid-Frequency Sonobuoy

Active multistatic sonar systems have become the preferred solution for shallow water undersea warfare missions. Most airborne active multistatic systems operate in the low frequency range to provide increased range and reverberation resistance. This workswell for large area search and localization missions. However, tactical follow up and target tracking are better accomplished by using higher frequencies, which provide high range resolution and speed computation. Tactical platforms such as the MH-60Rmulti-mission helicopter conduct tactical defensive and offensive operations in support of the battle group. They operate in a multistatic mode with the high power bow sonar source onboard the surface combatant and with their own onboard variable depthALFS sonar by deploying sonobuoys to receive and transmit the echoes to the helicopter. These systems operate at a higher frequency than where the current receiving sonobuoys operate. Therefore, to optimally operate in a multistatic mode with these higherfrequency sources, a new receiver is required which operates in the mid-frequency range of the ship sonars and ALFS. This new receiver will be compatible with existing digital RF links and employ in-buoy beamforming. This new receiver will be capable ofsignificant increase in weapon system operational performance over today's receivers. Developing a new sonobuoy with substantial noise discrimination capability and high gain at higher frequencies than previously achieved leads to smaller and lightersystems. This type of system capability is of interest to the undersea mapping, exploration, seismology and weather communities. Government agencies such as the National Oceanographic and Atmospheric (NOAA) and the Department of Commerce continuallyupgrade their measurement and data collection capability. These sensors would fulfill a need to provide in-situ measurements at frequencies not ordinarily measured. Also, their role in bottom mapping makes use of similar sensors that are much larger andcostly. By developing reliable, low cost sensor components, we can offer them much more capability and performance.