Mikhail Tsionskiy

Stevens Passive Acoustic System for underwater surveillance

The Stevens Passive Acoustic System allows the detection, tracking and classification of various surface and underwater sources of sound including surface vessels, swimmers, various types of divers, and unmanned underwater vehicles. This system was developed by Stevens in its Maritime Security Laboratory, which was established to support research in the area of Anti-Terrorism and Force Protection. The focus of this lab has been the persistent detection and classification of threats posed by surface and subsurface intruders utilizing a multiplicity of technologies. Using these capabilities, we have investigated the set of acoustic parameters fundamental to underwater acoustic threat detection, including diver acoustic signatures, acoustic transmission loss, and acoustic environmental noise. The Stevens Passive Acoustic System has successfully demonstrated surface ship detection and classification. The system provides simultaneous acquisition and analysis of acoustical signals using 4 hydrophones. The analysis functions includes arbitrary digital filtering, spectral analysis and cross-correlation for simultaneous processing of signals from several hydrophones, acoustical source separation, and determination of bearing for different targets relative to the central underwater mooring. The system also records and stores the complete raw acoustical data set, enabling further research and analysis of the acoustic signals. Novel acoustic methods of signal processing used in the system include: 1. Method of precise hydrophone localization. 2. Cross-correlation method for target bearing determination 3. Cross-correlation methods for extraction of target signatures from numerous sources. 4. Feature-based automated diver detection algorithm. 5. Measurements of the ship noise modulation spectrum that is related to propeller and shaft rotation (Detection of Envelope Modulation on Noise — DEMON method). The Stevens Passive Acoustic System has been used in tests in the Hudson River and NY Harbor where a large library of ship acoustic signatures has been collected. Several US Navy sponsored trials demonstrated the ability of the Stevens system for effective diver detection at distances up to 700m.

Nonlinear seismo-acoustic land mine detection: field test

The paper presents results of the field test of the nonlinear seismo-acoustic technique for detection and discrimination of land mines. The tests were conducted in summer 2001 at the U.S. Armys outdoor testing facilities. Plastic antitank mines (M19, VS1.6, VS2.2) and plastic antipersonnel mines (M14, VS50, TS50) were confidently detected at their maximum burial depths in both gravel and dirt lanes. Mine M14 is one of the smallest mines and is very difficult to detect by other techniques. The test proved that the nonlinear seismo-acoustic detection algorithm is very sensitive to AT and AP mines, while completely insensitive to false targets, such as rocks, chunks of metal or wood, thus promising to deliver high probability of detection with low false alarm rate. The results of the tests are in good agreement with the developed physical model of the seismo-acoustic detection.

Nonlinear seismo‐acoustic land mine detection: Field test

The paper presents results of the field test of the nonlinear seismo‐acoustic technique for detection and discrimination of land mines [D. Donskoy, SPIE 3392 (1998); 3710 (1999)]. The tests were conducted in summer 2001 at the U.S. Army outdoor testing facilities. Plastic antitank mines (M19, VS1.6, VS2.2) and plastic antipersonnel mines (M14, VS50, TS50) were confidently detected at their maximum burial depths in both gravel and dirt lanes. Mine M14 is one of the smallest mine and practically undetectable by the competitive techniques, including NQR, GPR, etc. The test proved that the developed nonlinear seismo‐acoustic detection approach is very sensitive to AT and AP mines, while completely insensitive to false targets, such as rocks, chunks of metal or wood, thus promising to deliver high probability of detection with low false alarm rate. The results of the tests are in good agreement with the developed physical model of the seismo‐acoustic detection. [Work supported by the U.S. Army Research Office ...

Optimization of seismo-acoustic landmine detection using dynamic mechanical impedances of mines and soil

Seismo-acoustic detection has demonstrated a high potential for the detection of land mines with a low probability of false alarms. A key element in the implementation and optimization of this new detection approach is the physical model of the mine-soil system. The validated model of the mine-soil system employs a mass-spring approach, which characterizes the dynamic response of the system using very few parameters derived from the dynamic mechanical impedances of the soil and the mines. This presentation describes the model and the results of the impedance measurements of live antitank and antipersonnel mines. The paper also deals with the optimization of the detection algorithm and its performance based on mine types, burial depth, and soil condition.

Stevens Passive Acoustic system for surface and underwater threat detection

The ability to safeguard domestic shipping and waterside facilities from threats associated with surface and underwater threats (vessels as well as divers) is critical to ensuring security for the maritime domain. Stevens Institute of Technology has been conducting numerous studies and associated field experiments of passive acoustic sensor applications for the detection, characterization, and tracking of surface and underwater threats, which lead to the development of the Stevens Passive Acoustic Detection System (SPADES). The extended diver detection tests were conducted in Newport, Rhode Island and in Den Helder, The Netherlands. Tests involving surface boats were conducted in various locations, including the New York Harbor, Miami, and San Diego. Acoustic tests in Lake Hopatcong, NJ were also conducted in controlled conditions using six distinct boats, including a Panga, a Go Fast boat, a jet ski, and a quiet electrical boat.

Acoustic signatures of small boats measured in controlled lake conditions

Measurements were conducted under controlled conditions at Lake Hopatcong, NJ, to compare acoustic signatures of various small boats. The tested boats included: an outboard-driven Panga, a multiple-outboard driven go-fast boat, an electric drive vessel, a personal watercraft (PWC), and two small outboard-driven rigid hull inflatable boats (RIBs). Stevens Passive Acoustic Detection System (SPADES) was used for acoustic measurements and the specially developed “Portable Vessel Data System” (PVDS) was used to record vessel position, speed, shaft RPM, and vessel orientation. Vessel acoustic Source Level measurements were conducted by comparing the recorded vessel acoustic signals with a signal generated by a calibrated emitter from the same point. Dependencies of acoustic signatures on boat speed and loading were also investigated. For several vessels, the Source Level decreased when its speed increased. Analysis of tonal components in the vessels acoustic signatures with Detection of Envelope Modulation on Noise (DEMON) allowed to determine the number of engines per boat and even the gear ratio for transformation of shaft rotation to the propeller rotation. [This work was supported by DHS S&T.]

Guidance of an unmanned underwater vehicle using a passive acoustic threat detection system

Divers and swimmers pose a potential water-side threat to assets in ports and harbors. Developing effective technologies and systems to detect, localize, and classify these threats is critical to protecting those assets. Once a potential threat has been identified, it is necessary to intervene to either deter or further classify a threat. UUVs are a technology that can be employed in this role, but there are challenges associated with re-acquiring a submerged threat with a UUVs sensors. This paper describes an experiment that used an acoustic system that can detect and localize a source and simultaneously steer a UUV to intercept and re-acquire the source.

Turbulence‐Induced Acoustic Emission of SCUBA Breathing Apparatus

Our initial study, [1], demonstrated that the primary originating source of vibration and subsequent acoustic emission from an underwater breathing apparatus is turbulent air flow pressure fluctuations occurring during the inhale phase of breathing. The process of energy release associated with the expansion of compressed air in the high pressure scuba tank, through the first stage regulator, results in a highly turbulent, unsteady, compressible air flow. The paper presents results of experimental investigation and fluid dynamic simulation of turbulence‐induced acoustic emission. The simulation reveals complex supersonic flow within the regulators valve and channel topology. The associated regulators air turbulent pressure pulsations and underwater acoustic emission are observed in a broadband frequency range.

High frequency modulation approach for the nonlinear seismo-acoustic detection of buried landmines

Buried in soil, landmines exhibit distinguishable nonlinear dynamic characteristics. These characteristics have been successfully used for nonlinear acoustic/seismic detection of both antipersonnel and antitank landmines. Despite a high potential of the nonlinear acoustic landmine detection technique, its utility is currently limited by a relatively high noise level of the LDV at frequencies typically used for landmine detection. To mitigate this limitation, we propose a modulation approach that exploits a nonlinear interaction of the low frequency resonance vibrations and higher frequency sound waves. The result of the modulation is manifested in a high frequency range as additional spectral components at the combination frequencies. The nonlinear response of the soil-mine dynamic system measured at the combination frequencies is used for the detection of the buried landmine. Exploring the higher frequency range has another benefit of using a directional high frequency sound source.