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 system includes at least five sensors configured and arranged to disambiguate the location of a shooter. By measuring the arrival times of the shockwaves of projectiles at each of the sensors and determining the differences in the arrival times among sensors, the systems and methods may determine the location of one or more sources of the projectiles. A distance of at least ten meters separates two or more of the sensors. Such a separation is advantageous because it allows the system to disambiguate multiple shooters by resolving the curvature of the shockwave.

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: Systems and methods for locating the shooter of supersonic projectiles are described. The system uses at least five, preferably seven, spaced acoustic sensors. Sensor signals are detected for shockwaves and muzzle blast, wherein muzzle blast detection can be either incomplete coming from less than 4 sensor channels, or inconclusive due to lack of signal strength. Shooter range can be determined by an iterative computation and/or a genetic algorithm by minimizing a cost function that includes timing information from both shockwave and muzzle signal channels. Disambiguation is significantly improved over shockwave-only measurements.

Abstract: 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.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. The system uses at least five, preferably seven, spaced acoustic sensors. Sensor signals are detected for shockwaves and muzzle blast, wherein muzzle blast detection can be either incomplete coming from less than 4 sensor channels, or inconclusive due to lack of signal strength. Shooter range can be determined by an iterative computation and/or a genetic algorithm by minimizing a cost function that includes timing information from both shockwave and muzzle signal channels. Disambiguation is significantly improved over shockwave-only measurements.

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 system includes at least five sensors configured and arranged to disambiguate the location of a shooter. By measuring the arrival times of the shockwaves of projectiles at each of the sensors and determining the differences in the arrival times among sensors, the systems and methods may determine the location of one or more sources of the projectiles. A distance of at least ten meters separates two or more of the sensors. Such a separation is advantageous because it allows the system to disambiguate multiple shooters by resolving the curvature of the shockwave.

Abstract: 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.

Abstract: The invention in various embodiments is directed to systems and methods for mitigating damage from a shock wave using a gas having a specific impedance less than air.

Abstract: The invention in various embodiments is directed to systems and methods for mitigating damage from a shock wave using a gas having a specific impedance less than air.

Abstract: Systems and methods for determining and disambiguating the location of the shooter of supersonic projectiles based on shockwave-only signals are described. Using several spaced sensors, an initial portion of the shockwave-only signals is sensed to determine Time-Differences-Of-Arrival (TDOA) for the sensor pairs. The resulting TDOAs are used to determine the gradient of curvature of the shockwave wavefront on the sensors. The gradient of curvature is then used to determine the disambiguated projectile trajectory.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. The system uses at least five, preferably seven, spaced acoustic sensors. Sensor signals are detected for shockwaves and muzzle blast, wherein muzzle blast detection can be either incomplete coming from less than 4 sensor channels, or inconclusive due to lack of signal strength. Shooter range can be determined by an iterative computation and/or a genetic algorithm by minimizing a cost function that includes timing information from both shockwave and muzzle signal channels. Disambiguation is significantly improved over shockwave-only measurements.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. The system uses at least five, preferably seven, spaced acoustic sensors. Sensor signals are detected for shockwaves and muzzle blast, wherein muzzle blast detection can be either incomplete coming from less than 4 sensor channels, or inconclusive due to lack of signal strength. Shooter range can be determined by an iterative computation and/or a genetic algorithm by minimizing a cost function that includes timing information from both shockwave and muzzle signal channels. Disambiguation is significantly improved over shockwave-only measurements.

Abstract: Systems and methods for compensation of sensor degradation in multi-shooter detection systems are described. In such systems, shooter position and trajectory can be estimated precisely from the shockwaves produced at the plurality of sensors by the incoming shots. However, sensor positions can shift and the performance of some sensors may degrade for various reasons. To compensate for sensor degradation that may occur over the life of a long-deployed system, the shooter estimation algorithms are dynamically adapted by performing a least-squares regression analysis of the shockwave arrival times to obtain a time residual for each shot, observing multiple shots, and weighting the individual contributions of the sensors as a function of the time residuals for the multiple shots.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. The system uses at least five, preferably seven, spaced acoustic sensors. Sensor signals are detected for shockwaves and muzzle blast, wherein muzzle blast detection can be either incomplete coming from less than 4 sensor channels, or inconclusive due to lack of signal strength. Shooter range can be determined by an iterative computation and/or a genetic algorithm by minimizing a cost function that includes timing information from both shockwave and muzzle signal channels. Disambiguation is significantly improved over shockwave-only measurements.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. Muzzle blast signals are neither sought nor required. The system uses at least two sensors, with each sensor having a 3-axis accelerometer. The sensors are spaced apart at least 1 meter and have each a diameter of about one centimeter. The three accelerometer signals of each sensor represent pressure gradients and are processed to find the shockwave arrival angle unit vector, the shockwave arrival time instant and peak pressure. Noise signals seldom cause false detections with this sensing method because the sensors have maximum sensitivity at the high frequency characteristics of shockwaves, while their sensitivity to the low frequency characteristics of ambient noise is relatively low.

Abstract: The invention provides, in various embodiments, a transducer for generating hyper-directional sound beams, and a system and method employing a hyper-directional sound transducer for producing pressure gradients and forces across stationary and moving objects.

Abstract: An improved system for sensing ground motion is provided. The system generally comprises a shell and a case within the shell and connected by a suspension. The mass of the case is greater than the mass of the shell. An electrode within the shell detects relative motion between the shell and the case.

Abstract: A low cost and highly accurate sniper detection and localization system uses observations of the shock wave from supersonic bullets to estimate the bullet trajectory, Mach number, and caliber. If available, muzzle blast observations from an unsilenced firearm is used to estimate the exact sniper location along the trajectory. The system may be fixed or portable and may be wearable on a user's body. The system utilizes a distributed array of acoustic sensors to detect the projectile's shock wave and the muzzle blast from a firearm. The detection of the shock wave and muzzle blast is used to measure the wave arrival times of each waveform type at the sensors. This time of arrival (TOA) information for the shock wave and blast wave are used to determine the projectile's trajectory and a line of bearing to the origin of the projectile. A very accurate model of the bullet ballistics and acoustic radiation is used which includes bullet deceleration.

Abstract: A method for reducing the time, cost and apparatus required for monitoring the geometry of the oil/water, oil/gas, or gas/water interface in an underground reservoir. By strategically placing sources and sensors, and by fixing the sensors to the solid earth surface beneath the water, and by knowing the velocity fields in the overburden, the changing edges and geometry of the oil may be determined with significantly reduced data gathering. The strategic positions of the sources and receivers is determined by referencing to the known geometry from past surveys. In addition the velocity of the overburden is known by these prior surveys. In addition, higher resolution of reflectivity areas is achieved by use of sound sources capable of generating higher frequencies compensated for the earth's attenuation and by utilizing long integration times to improve signal to noise ratio. These sound sources can be smaller than prior art sources since they provide directed beams of narrower widths.

Abstract: A low cost and highly accurate sniper detection and localization system uses observations of the shock wave from supersonic bullets to estimate the bullet trajectory, Mach number, and caliber. If available, muzzle blast observations from an unsilenced firearm is used to estimate the exact sniper location along the trajectory. The system utilizes a distributed array of acoustic sensors to detect the leading edge of a projectile's shock wave and the muzzle blast from a firearm. The detection of the shock wave and muzzle blast is used to measure the wave arrival times of each waveform type at the sensors. This time of arrival (TOA) information for the shock wave and blast wave are used to determine the projectile's trajectory and a line of bearing to the origin of the projectile. A very accurate model of the bullet ballistics and acoustic radiation is used which includes bullet deceleration.