Testing of new seismic sensors for footstep detection and other security applications

Abstract

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.

Low-frequency signals detection and identification as a key point of software for surveillance and security applications

“…Unfortunately, in real conditions especially at maximum distances where footstep detection is possible, the envelope pattern is much worse. An example of such envelope is presented in Figure 3, when distance between a walking person and a GS-20DX geophone is about 30-35 meters with a low background noise level [2]. We have the same ambiguous footstep signal envelope in case of using a seismic string instead of single geophone.…”

New sensitive seismic cable with imbedded geophones

“…Typically, for high environment noise area, spacing can be about 8 to 12 meters between geophones. For low environment noise area spacing can be up to 100 meters (see field-testing results of GSS seismic sensors [10]). A cable with up to 10 sensors can be connected to one processing channel.…”

“…As reported earlier [7,8,10], a sensor was placed for testing in a different orientation (vertical, horizontal, and at 45˚ angle) on the vertically vibrating surface, as shown in Figure 1. Output of all sensors was connected to an analog-to-digital converter (ADC) without additional amplification.…”

New seismic unattended small size module for footstep detection

“…It also allows us to use in the future the novel GSS miniature seismic sensor that has significantly better sensitivity and frequency characteristics than the existing seismic sensors [6][7][8][9][10].…”

“…In the future, the use of the GSS-miniature sensor [6][7][8][9][10] can additionally improve the unattended seismic detector performance characteristics.…”