Designers and consumers of various security, intelligence, surveillance and reconnaissance (ISR) systems as well as
various unattended ground sensors pay most attention to their commonly used performance characteristics such as
probability of a target detection and probability of a false alarm. These characteristics are used for systems comparison
and evaluation. However, it is not enough for end-users of these systems as well as for their total/final effectiveness
assessment. This article presents and discusses a system approach to an efficiency estimation of the security and ISR
systems. Presented approach aims at final result of the system's function and use. It allows setting up reasonable
technical and structural requirements for the security and ISR systems, to make trustworthy comparison and practical
application planning of such systems. It also allows finding forward-looking, perspective ways of systems development.
Presented results can be guidance to both designers and consumers.
KEYWORDS: Signal detection, Signal processing, Sensors, Infrared sensors, Surveillance, Target detection, Acoustics, Signal to noise ratio, Active sensors, Submerged target detection
Various passive as well as active surveillance and security systems try to detect and identify very low frequency signals.
Diversity of such real time working systems is very broad. Those are seismic, acoustic, hydroacoustic, IR, ultrasound,
etc. systems. Detected target spectrum is also broad: from human motion on the ground surface and under water to lownoise
submarines. In real application corresponding signals have poor signal-to-noise ratio, unstable shape and
amplitude, short duration, and even missing parts of the signal. This paper describes test records of some raw seismic,
acoustic, acoustic-seismic, hydroacoustic, and IR signals with proper characteristics. We investigate those signals
specifics and possible approach to target oriented reliable signal processing that allows drastically increasing detection
range and reducing false alarm rate. We also report on the preliminary field-testing that was implemented with active
ultrasonic detector.
KEYWORDS: Sensors, Signal detection, Target detection, System identification, Detection and tracking algorithms, Environmental sensing, Seismic sensors, Signal processing, Amplifiers, Roads
General Sensing Systems (GSS) has achieved outstanding and verifiable results in the design and development of
various seismic detection and identification systems. These results include, in particular, new seismic miniature
sensor design and seismic signal recording and research for many traditional and nontraditional targets - walking,
running and jumping persons, heavy and light vehicles, helicopters and aircraft, ships, trains, etc. These results also
include the hardware design for up-to-date unattended seismic detection and identification systems. The main
outcome of our effort is detection and identification algorithms and corresponding software for personnel and
vehicle detection and identification which were tested in real environment conditions. These algorithms provide a
zero false alarm rate with no target missing and can be used for many real and important military and homeland
security applications. We also report on future seismic detection and identification systems for various military and
civil applications.
KEYWORDS: Sensors, Signal detection, Detection and tracking algorithms, Target detection, Electronic filtering, Roads, Plano, Signal processing, Connectors, Seismic sensors
General Sensing Systems (GSS) has developed a new seismic, unattended small size module that detects and identifies not only human footsteps but also light and heavy vehicles with near zero false alarm rates. This module has extremely low power consumption and can operate for several months using standard commercial batteries. This paper describes the design of this module that can communicate with any radio transducer or computer. We also report on the preliminary lab and field testing that was implemented in various environment conditions. We show that the new unattended, small size detection module demonstrates the same reliable performance as our previous footstep detection systems and has the added capability of detecting and identifying light and heavy vehicles.
General Sensing Systems (GSS) has achieved outstanding and verifiable results in the design and performance of
seismic systems with near zero false alarm rates for the detection of walking and running persons. These results were
realized in a number of detection systems and in particular in small size seismic detection modules. Preliminary testing
of these seismic modules in various environment noise conditions shows that such small unattended modules can be
successfully used for other target detection. Potential target sets can include light and heavy vehicles, helicopters,
aircraft, and ships. This paper describes preliminary results of such target detection and preliminary experimental data
about corresponding detection range. We show that the new unattended, small size detection module demonstrates
reliable performance in various environment conditions.
Seismic detection systems for homeland defense and security applications are an important additional layer to perimeter, border and zone protection. General Sensing Systems has been developing a novel method and corresponding software for footstep detection with a near zero false alarm rate. This method has been realized in a number of detection systems. The testing of the GSS seismic systems in various environment noise conditions showed that such systems can be successfully used for other target detection. Such "unconventional" targets can include light and heavy vehicles, trains, helicopters and ships. This paper describes the signal characteristics of such targets and the preliminary experimental data on the corresponding detection range. We also report on the seismic sensor and seismic system requirements for target detection.
General Sensing Systems (GSS) has achieved outstanding and verifiable results in the design and performance of seismic systems with near zero false alarm rates for the detection of walking, running, and jumping persons. These results have been reported in various homeland security and military applications. GSS has been developing a new seismic, unattended small size module for footstep detection. This paper describes our design for the module, which includes the two-board and one-board versions - fitting into various consumer applications. Communication interface versions, which are used in the detection module, allow the communication with any wireless surveillance network. We also report on the preliminary lab and field-testing that was implemented in various conditions. We show that the new unattended, small size detection module demonstrates the same reliable performance as our previous full size systems.
Seismic detection systems for homeland security applications are an important additional layer to perimeter and border protection and other security systems. General Sensing Systems has been developing low mass, low cost, highly sensitive geophones. These geophones are being incorporated within a seismic cable. This article reports on
the concept of a seismic sensitive cable and seismic sensitive ribbon design. Unlike existing seismic cables with sensitivity distributed along their lengths, the GSS new cable and ribbon possesses high sensitivity distributed in several points along the cable/ribbon with spacing of about 8-12 to 100 meters between geophones. This cable/ribbon is highly suitable for design and installation in extended perimeter protection systems. It allows the use of a mechanical cable layer for high speed installation. We show that any installation mistakes in using the GSS seismic sensitive cable/ribbon have low impact on output seismic signal value and detection range of security systems.
KEYWORDS: Sensors, Seismic sensors, Defense technologies, Target detection, Signal detection, Defense and security, Homeland security, Manufacturing, Signal processing, Sensing systems
General Sensing Systems (GSS) has been developing seismic sensors for different security and military applications for the past several years. Research and development in this area does not have a single-value purpose as security and military applications are of a broad variety. Many of the requirements for seismic sensors are well known. Herein we describe additional requirements for seismic sensors that are not at the center of common attention and associated with high performance seismic sensors. We find that the hard issues related to "remote" deployment/installation methods can be solved, given the seismic sensor does not have the usual single-axis sensitivity, but sensitivity to arbitrary oriented impact/vibrations. Our results show that such a sensor can be designed, in particular based on electret materials. We report that traditional frequency response curve linearity is not always the appropriate goal. Such issues as useful signal frequency band and an interference immunity should be directly taken into account. In addition, the mechanical oscillator of the seismic sensor should have a very broad dynamic range about 120dB, or an adjustable sensitivity for use in various tactical applications. We find that increasing sensitivity is not so much needed as is reducing of the seismic sensor sensitivity threshold. The lower sensitivity threshold in higher target detection range can be obtained in low noise environmental conditions. We will also show that the attempt to design and manufacture a universal seismic sensor for every possible application seems unreasonable. In every respect it makes sense to design a seismic sensor set, which can fit and satisfy all plurality of the applications and multi objective requirements.
General Sensing Systems (GSS) has been successfully developing a new sensor for the past several years. Herein we describe the lab and field testing of this small size, extremely lost cost and high performance seismic sensor intended for up-to-date security and military systems. This article delivers the latest results of the wide-ranging laboratory and field tests of this new sensor. During the testing, GSS’s new sensor was compared with the leading commercially available geophones, the GS-14-L3 and GS-20DX geophones produced by Geo Space Corporation. The obtained results confirm our pilot lab testing [1] in terms of the advantages of new sensor. The results show that the new GSS sensor has an expanding frequency response range in both the low and high frequency areas. The GSS sensor also has the highest sensitivity among all the compared geophones as well as a lower sensitivity threshold. This point is significant for real signal interpretation in heavy noise environments and is a significant advantage of the GSS sensor’s performance in comparison to that of existing commercial geophones. The comparative field test results show that the GSS sensor allows to detect footstep signal by almost 3 times larger distance between the sensor and walking person. This is crucial for increased detection range of seismic-acoustic reconnaissance systems. In general, the results show it is possible to manufacture very small and inexpensive seismic sensors with significantly improved performance characteristics.
General Sensing Systems (GSS) has developed a sensor based on electrets material. Herein we describe the creation and lab testing of this very small and high performance seismic sensor intended for up-to-date security and military systems. This article delivers the first results of laboratory tests of this small size and extremely low cost new sensor. This new sensor was compared with the most popular geophones, the GS-14-L3 and GS-20DX geophones produced by Geo Space Corporation. The results show that the new, GSS sensor has an expanding frequency response range in both the low and high frequency areas. This is crucial for increased detection range of seismic-acoustic and hydro acoustic reconnaissance systems. The new, GSS sensor also has the highest sensitivity among all the compared geophones as well as a lower sensitivity threshold. When the amplitude of vibrations is very small, the GS-14-L3 and GS-20DX geophones, for example, miss signals-whereas the new sensor has a good response. Specifically, this performance characteristic of the new GSS sensor also allows the development of reconnaissance systems with a high detection range. Test results also show that the new sensor demonstrates good signal discrimination, ensuring efficient signal interpretation. In general, the results reported here show that the use of electrets materials enables the manufacture of very small and inexpensive seismic-acoustic and hydro acoustic sensors with improved performance characteristics.
Seismic footstep detection-based systems are very important for various homeland security and military applications. Their performance and usefulness strongly depends on the characteristics of the seismic sensors. Unfortunately, currently available seismic sensors do not provide in satisfactory results. This paper describes the main issues of using seismic sensors for detection purposes and shows the key disadvantages of the most popular commercial seismic sensors/geophones. According to our results, the following are the key issues of poor seismic sensor performance:
- Poor response to low frequency signals, leading to decrease of the detection range of targets
- Unsatisfactory sensitivity threshold, causing missing low level seismic signals from outlying targets
- Long damping signal time and corresponding low accuracy response, leading to problems with outlying target detection in high level noise environments
- Low noise immunity from electromagnetic interference making seismic sensor operation in radar installation areas unreliable
- Relatively bulky size and high price, which prevents extensive use of seismic sensors
In addition, we have formulated objective requirements for seismic sensors to be used in defense and security applications
Performance of seismic security systems relies on the particular application of the characteristics of seismic sensors. Current seismic sensors do not yield best possible results. In addition to identifying the requirements for optimal seismic sensors, we have developed seismic sensors for defense and security applications. We show two different types of seismic sensors: a miniscule, extremely low cost sensor and a bulk sensor.
The miniscule, extremely low cost sensor is an electret-based geophone for both seismic and acoustic detection systems. This geophone detects a small size object - i.e. a walking/running/crawling person or a small underwater vehicle-that moves on the surface, underground, and/or in the water. It can also detect large size objects-i.e. heavy vehicles, trucks, tanks-as well as be used in littoral warfare. The electret-based design significantly improves technical characteristics achieving performance uniqueness: expanded frequency response range in the low frequency area, improved sensitivity threshold and accuracy response, and improved sensor's protection from electromagnetic interference.
The bulk sensor has an extremely large detection surface, a nanocomposite body in special form casing, and a special electronic circuit. These sensors allow detection of footstep signals in high ambient seismic noise levels. However, installation requires significant installation groundwork effort.
KEYWORDS: Signal detection, Interference (communication), Environmental sensing, Homeland security, Sensors, Electronic filtering, Defense and security, Seismic sensors, Signal to noise ratio, Sensing systems
The development of security systems based on seismic footstep detection is critical for homeland security and defense applications. The performance of these systems depends on various factors, including noise and signal levels in the real environment. This paper describes the effect of different real seismic noise sources -- such as highways, railroads, operating machinery, trees and shrubs swaying in the wind -- on seismic security system performance as these sources can be located close to the detection area. It is demonstrated that by moving away from these sources, the noise source spectra constantly change. Additionally, we present accurate results for the behavior of footstep signal reduction versus distance for a moving (walking/running) person and the seismic sensors. The effects of seismic signal summation and the noise associated with a number of sensors in environments such as ledge rock and soft earth surface is also discussed.
Seismic footstep detection based systems for homeland security applications are an important additional layer to perimeter protection and other security systems. This article reports seismic footstep signal characterization for different signal to noise ratios. Various footstep signal spectra are analyzed for different distances between a walking person and a seismic sensor. We also investigated kurtosis of the real footstep signals under various
environmental and modeled noises. We also report on the results of seismic signal summation from separate geophones. A seismic signal sum spectrum obtained was broader than that obtained from a single sensor. The peak of the seismic signal sum was broader than that from the footstep signal of the single sensor. The signal and noise
spectra have a greater overlap for a seismic signal sum than that from a single sensor. Generally, it is more difficult to filter out the noise from the sum of the seismic signals. We show that the use of the traditional approach of spectrum technology and/or the statistical characteristics of signal to noise of reliable footstep detection systems is not practical.
Tactical capabilities of single and three axis geophones for seismic detection and bearing estimation for homeland security and defense applications are described. It is shown that typically three axis geophones yield a high bearing estimation error. An alternate bearing estimation approach is based on using the time delay in footstep signal detection from three triangulated single axis vertical geophones. In this approach the standard deviation of the bearing estimation error is less than 12 degrees for a walking person distance of 10 to 70m and geophone distances of 8 to 9 m.
We find that using the three-axis geophone approach makes it harder for path tracking and bearing estimation within the tactical zone area. We report that a single-axis geophone approach for riangulation of walking person is more effective. In addition, road monitoring is also more efficient using a single-axis geophone approach. We compare
the relative and absolute improvement of bearing estimation probability for road monitoring using three single-axis geophones versus 1, 2 and 3 three-axis geophones. We will also discuss the use of single axis vertical geophone sets for monitoring various zone sizes.
Development of advanced seismic footstep detection systems for perimeter and zone protection can offer new method for improved homeland security and defense applications. High false alarm rates associated with current seismic security systems has been a formidable obstacle in their widespread adoption. This paper describes a novel method for seismic footstep detection in which false alarms are inhibited and virtually eliminated. In addition, a
significant increase in detection range for seismic security systems is also reported.
Proprietary software was specifically developed to improve processing of the seismic signals. This software allows one to uniquely analyze over three-dozen signal shape parameters within the detected seismic signal. This novel software enables real time signal analysis, thus effectively offering a more efficient and effective alternative to using trained personnel.
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