Raytheon Bbn Technologies Corp.

Bbn Technologies Corporation

John N Stanley

James Edwin Barger

Ronald Bruce Coleman

The systems and methods described herein include an acoustic sensor having piezoelectric material housed in a cartridge and sealed with a solid nonporous stainless steel cover. The systems include additional elements to tune the performance of the acoustic sensor for measuring shockwaves on the surface of an aircraft, such as a helicopter. In particular, the system includes several vibration isolating elements including foam pads and O-rings disposed between the cartridge and the cover for isolating the piezoelectric material from aircraft vibration and turbulence. Additionally, the systems and methods include circuitry for converting analog electrical signals generated by the piezoelectric material, in response to acoustic signals, to digital electrical signals.

Acoustic sensors for detecting shooter locations from an aircraft

A sensor assembly suitable for use in an airborne shooter localization system. The sensor assembly has a pressure sensor subassembly with a pressure transducer positioned to detect pressure variations associated with a shock wave from a passing projectile or the muzzle blast following the shock wave. To substantially increase the signal to noise ratio for measurements of the shock wave, the pressure sensor subassembly attenuates pressure fluctuations triggered by turbulent airflow over the surface of the subassembly more than it attenuates the shock wave. This preferential attenuation is provided by separating the pressure transducer from the surface of the sensor assembly by a cavity large enough that the pressure fluctuations are substantially attenuated as they propagate across the cavity. Additionally, features of a housing that holds the pressure sensor subassembly facilitate use on an aircraft. Those features include flexibility that allows the sensor assembly to conform to curved surfaces, a skin that provides resistance to environmental conditions and allows the sensor assembly to be attached with an adhesive, and a body region that provides high vibrational impedance to prevent low frequency mechanical vibrations from being coupled to the pressure transducer.

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Wilmington, MA, United States of America

John N Stanley