Multi-Mode Electromagnetic Target Discriminator (METD) Sensor System
With an estimated 100 million mines and countless millions of acres of land contaminated with unexploded ordnance (UXO) world- wide there is a need for a sensor system and methods that can detect and identify large and small metal objects buried in the soil. In addition, during armed conflict, there is a need for mine detection and neutralization in real-time or near real time. A commonly used sensor for mine and UXO detection is the electromagnetic induction (EMI) metal detector. Conventional EMI detectors using either frequency-domain (FD) or time-domain (TD) eddy current methods can detect small targets at shallow depths and large metal targets at deeper depths. However other metal objects commonly found in the environment form a major problem in identifying mines and create many false alarms. These false alarms cost time and money when trying to clear an area of the real mines. Metal targets need to not only be identified but also classified in real-time.
The Johns Hopkins University Applied Physics Laboratory has developed and is in the patent process of a metal detection and discrimination that operates in both the time and frequency domain modes with the capability of optimizing its transmitter and receiver antenna configuration. One embodiment of this invention is a multi-mode electromagnetic target discrimination sensor system for transmitting an electromagnetic signal and receiving a reflected signal from at least one target comprising a variable inductance antenna having a variable inductance transmitter and receiver for varying at least one operating bandwidth, sensitivity and size of the antenna. The unit also has a processor for alternating between a time domain and a frequency domain operating mode while controlling the variation of the inductance of the variable inductance antenna based on the current operating mode. The unit also has at least one processing algorithm for receiving signals from the receiver, discriminating the targets and outputting the results.
Patent Status: U.S. patent(s) 6967574 issued.CONTACT: