Proceedings Article | 15 September 2004
Proc. SPIE. 5403, Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security and Homeland Defense III
KEYWORDS: Microelectromechanical systems, Oscillators, Seismic sensors, Sensors, Electrodes, Electromagnetic interference, Defense technologies, Nanocomposites, Electronic circuits, Signal detection
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.
