Abstract: 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.

Abstract: 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.

Abstract: The systems and methods described herein provide military personnel with a swift and accurate means to return fire at a detected shooter. In particular, the systems and methods described herein relate to an indicator for a weapon sight. In some embodiments, the indicator is electromechanical. In some embodiments, the indicator is configured to be moveable such that when the weapon sight is aligned with the indicator, the weapon points in the direction of the detected shooter. In some embodiments, the indicator is attached to the weapon itself, while in other embodiments, the indicator is attached to the weapon mount. The weapon may be located on a ground vehicle, aircraft, or may be portable. In some embodiments, the system includes a processor configured to receive a shooter's location, determine the position of the indicator based on the received shooter location, and control the indicator to move into the determined position.

Abstract: The systems and methods described herein relate to an airborne shooter detection system having a plurality of sensors coupled to the body of an aircraft such as a helicopter. The sensors are arranged to receive shockwave-only signals. The received signals are analyzed to determine an unambiguous shooter location. The analysis may include measuring the arrival times of the shockwaves of projectiles at each of the sensors, determining the differences in the arrival times among sensors, computing a set of ambiguous solutions corresponding to a shooter, and clustering this set of solutions to determine the unambiguous shooter location. The systems and methods described herein may also be used to determine if multiple shooters are present, and subsequently determine the shooter locations for each of the multiple shooters.

Abstract: The systems and methods described herein relate to an airborne shooter detection system having a plurality of sensors coupled to the body of an aircraft such as a helicopter. The sensors are arranged to receive shockwave-only signals. The received signals are analyzed to determine an unambiguous shooter location. The analysis may include measuring the arrival times of the shockwaves of projectiles at each of the sensors, determining the differences in the arrival times among sensors, computing a set of ambiguous solutions corresponding to a shooter, and clustering this set of solutions to determine the unambiguous shooter location. The systems and methods described herein may also be used to determine if multiple shooters are present, and subsequently determine the shooter locations for each of the multiple shooters.

Abstract: Disclosed are systems and methods that can be used to detect shooters. The systems and methods described herein use arrival times of a shockwave, produced by a shot, at a plurality of sensors to assign weights to each of the plurality of sensors, and determine a shot trajectory based on the assigned weights.

Abstract: The systems and methods described herein provide military personnel with a swift and accurate means to return fire at a detected shooter. In particular, the systems and methods described herein relate to an indicator for a weapon sight. In some embodiments, the indicator is electromechanical. In some embodiments, the indicator is configured to be moveable such that when the weapon sight is aligned with the indicator, the weapon points in the direction of the detected shooter. In some embodiments, the indicator is attached to the weapon itself, while in other embodiments, the indicator is attached to the weapon mount. The weapon may be located on a ground vehicle, aircraft, or may be portable. In some embodiments, the system includes a processor configured to receive a shooter's location, determine the position of the indicator based on the received shooter location, and control the indicator to move into the determined position.

Abstract: Shockwave-only solutions that estimate shooter position and shot trajectory are extremely sensitive to the quality and precision of the shock time-of-arrival (TOA) measurements as well as the accuracy to which relative sensor positions in space are known. Over the life of a long-deployed system, the sensor positions can shift and the performance of some sensors may degrade for various reasons. Such changes can degrade the performance of deployed shooter estimation systems. Disclosed are systems and methods that can be used to calibrate sensor positions based on shock and muzzle measurements processed from a series of shots fired from a known location and in a known direction, as well as an approach for dynamically adapting shock-only shooter estimation algorithms to compensate for sensor degradation and/or loss.

Abstract: Systems and methods for locating the shooter of supersonic projectiles based on shockwave-only measurements are described. Muzzle blast signals are neither sought nor required. The system uses at least five, preferably seven, acoustic sensors that are spaced apart at least 1 meter. The sensor signals are acquired with a time resolution in the order of microseconds and processed to find and disambiguate the shockwave arrival angle unit vector. Two different Time-Difference-Of-Arrival (TDOA) measurement techniques are described, with one technique using counters in each signal channel and the other technique using cross-correlation between signal channels. A genetic algorithm can be used to efficiently disambiguate the results.

Abstract: A method and device for generating a high amplitude sound wave is provided. The device includes a housing having an open end. A piston is slidably disposed in the open end of the housing and forms a chamber for holding a pressurized liquid. The pressurized liquid acts on the piston to move the piston relative to the housing. A latch is operable to fix the piston relative to the housing and to release the piston. Upon release of the latch, the piston moves relative to the housing to generate the sound wave. In the method of the present invention, a piston is fixed relative to a housing to form a chamber between the housing and the piston. The chamber is filled with a pressurized fluid and the piston is released to allow the pressurized fluid move the piston relative to the housing and generate the sound wave.

Abstract: A sound generating device for generating a sound wave in a body of water is provided. The device includes a pair of axially aligned pistons. An electromagnet is mounted on at least one of the pistons. Activation of the electromagnet causes the pistons to move towards each other. A spring is positioned between the pistons and biases the pistons away from each other. Provision is made for changing the spring rate during operation so that the device will operate at mechanical resonance throughout the intended frequency range. A control device controls the current flowing through the electromagnets. The current is controlled to induce a predetermined variance of axial displacement between the pistons and thereby generate a sound wave.