The OptaSense® Distributed Acoustic Sensing (DAS) technology can turn any cable with single-mode optical fiber into a very large and densely sampled acoustic/seismic sensor array—covering up to a 50 km aperture per system with "virtual" sensor separations as small as 1 meter on the unmodified cable. The system uses Rayleigh scattering from the imperfections in the fiber to return the optical signals measuring local fiber strain from seismic or air and water acoustic signals. The scalable system architecture can provide border monitoring and high-security perimeter and linear asset protection for a variety of industries—from nuclear facilities to oil and gas pipelines. This paper presents various application architectures and system performance examples for detection, localization, and classification of personnel footsteps, vehicles, digging and tunneling, gunshots, aircraft, and earthquakes. The DAS technology can provide a costeffective alternative to unattended ground sensors and geophone arrays, and a complement or alternative to imaging and radar sensors in many applications. The transduction, signal processing, and operator control and display technology will be described, and performance examples will be given from research and development testing and from operational systems on pipelines, critical infrastructure perimeters, railroads, and roadways. Potential new applications will be discussed that can take advantage of existing fiber-optic telecommunications infrastructure as “the sensor”—leading to low-cost and high-coverage systems.
DARPA has conducted a number of field measurement, modeling, and system design trade study efforts to determine the
most effective way of linking Unattended Ground Sensors (UGS). These network links are needed for both
collaborative operations and data and information exfiltration to users. This paper provides an informal summary of the
findings of this work.
BBN has developed flexible counter-sniper technology capable of shooter and bullet trajectory localization using fixed, vehicle-mounted, and/or body-worn microphone sensors. The proof of principle (POP) systems developed are accurate, low-cost, lightweight, and easy to install and use. The use of both supersonic bullet shock waves, and/or the muzzle blast, allows detection and localization of shooters with intentional or accidental muzzle blast suppression, or with subsonic rounds. This makes the system capable of finding shooters firing from within buildings or vehicles. It also requires fewer sensor installations per unit area and increases system robustness to the noise and reverberation present in urban settings. In this paper we first summarize the current POP system hardware and software configurations and show the results of government testing in urban and rural environments for military applications. Following this, cost and performance issues for urban law enforcement applications are presented, and performance predictions for various system configurations in an urban street monitoring scenario are given.
KEYWORDS: Sensors, Acoustics, Data modeling, Data communications, Global Positioning System, Data processing, Antennas, Wavefronts, Data acquisition, Telecommunications
BBN has developed, tested, and fielded pre-production versions of a versatile acoustics-based counter-sniper system. This system was developed by BBN for the DARPA Tactical Technology Office to provide a low cost and accurate sniper detection and localization system. The system uses observations of the shock wave from supersonic bullets to estimate the bullet trajectory, Mach number, and caliber. If muzzle blast observations are also available from unsilenced weapons, the exact sniper location along the trajectory is also estimated. A newly developed and very accurate model of the bullet ballistics and acoustic radiation is used which includes bullet deceleration. This allows the use of very flexible acoustic sensor types and placements, since the system can model the bullet's flight, and hence the acoustic observations, over a wide area very accurately. System sensor configurations can be as simple as two small four element tetrahedral microphone arrays on either side of the area to be protected, or six omnidirectional microphones spread over the area to be monitored. Increased performance can be obtained by expanding the sensor field in size or density, and the system software is easily reconfigured to accommodate this at deployment time. Sensor nodes can be added using wireless network telemetry or hardwired cables to the command node processing and display computer. The system has been field tested in three government sponsored tests in both rural and simulated urban environments at the Camp Pendleton MOUT facility. Performance was characterized during these tests for various shot geometries and bullet speeds and calibers.
Traffic data collection studies and management systems require accurate and cost-effective sensors for roadway volume, vehicle speed, and vehicle type classification. In this study, we compare the performance of inexpensive and non-intrusive sensing using video cameras, passive acoustic microphone arrays, active ultrasonic acoustic ranging and Doppler sensors, Doppler radar, and passive infrared sensors in these applications. Using data taken on a highway near Boston, Mass. the various sensor types are coupled with appropriate signal processing for counting, speed estimation, and vehicle type classification. Emphasis is placed on understanding the fundamental limitations of each sensor type, and an interactive system for ground-truth database construction and comparison with the detected outputs and intermediate signal processor products is described. This system is essential for understanding the reasons for the observed performance.
Conference Committee Involvement (3)
Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security, Defense, and Law Enforcement Applications XVI
10 April 2017 | Anaheim, CA, United States
Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security, Defense, and Law Enforcement Applications XV
18 April 2016 | Baltimore, MD, United States
Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security, Defense, and Law Enforcement Applications XIV
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