Instrumentation

Magnetic and EM Sensors and Recorders

We manufacture highly effective magnetic sensors (fluxgate and induction coil), low-frequency electromagnetic sensors, and various electromagnetic antennas. As well, we have developed a system to acquire, process, and analyze the data from those sensors and antennas. This system can detect, track, and characterize targets with magnetic and low-frequency electromagnetic signatures. It can provide unattended ground sensor project for targets like tanks, trucks, scud launchers, and rifles. It can also assist UAV-based systems for underground facility detection. It detects the magnetic field perturbation produced by ferrous objects; it can detect a rifle at 70 feet and a tank at several hundred. It can detect the low-frequency field perturbation produced by underground conductors. And it can detect emissions from various targets. We have developed several system components and demonstrated an integrated, real-time system. Some specific modules are explained in further detail.

Fluxgate Magnetometer

We have developed extremely sensitive fluxgate magnetometers. These provide room temperature operation and sense a few PT at 1Hz. They can detect a rifle at 70 feet and a hand grenade at 3 feet. These tri-axial sensors can be used is conjunction with our signal acquisition and analysis system. They can detect, track, and classify various non-cooperative targets. Other applications exist in geophysical exploration, surveillance, and underwater exploration.

Low-Frequency Electromagnetic Sensors

The fluxgate sensors measure the magnetic field at a frequency range from dc to a few tens of Hz. For frequencies above tens of Hz, induction coils provide the best sensitivity. We have developed induction coils with sensitivity better than FT. These are the most sensitive induction coils in the world and can operate from 1 MHz to hundreds of KHz. Combining fluxgate and induction coils provides the ideal sensor suit for complete electromagnetic spectral characterization, from dc to hundreds of KHz. We have developed various units with different sizes and responses.

Magnetic Array for Tracking and Characterization

Multiple magnetic sensors make up a networked configuration to detect, track, and classify various non-cooperative targets. Most of this work was supported by the DARPA contract “Magnetic Array.” We have developed a novel data acquisition and analysis system (real-time) for various tests and system optimization. The real-time system, Advanced Digilyzer, has found uses in field test, data acquisition, real-time tracking, and characterization of various non-cooperative targets.

CRS Real-Time Magnetic Tracking Software

This Windows® 95-based system uses Digital Signal Processors in conjunction with the host processor to acquire and process magnetic data. The system can track vehicle movement in real-time, with graphic displays of raw data as well as vehicle tracks. It bases its tracks and classifications on induced field perturbations. Residual fields need to be modeled. The system relies on a pair of Analog Devices SHARC DSP chips to perform the analysis necessary to calculate the vehicle position in real time. The host processor manages the plotting, the data logging, and the DSPs.

Features include:

Electromagnetic Modeling Tools for Low Frequency Electromagnetic Modeling

A fully 3-D electromagnetic modeling tool models the electromagnetic field perturbation produced through underground facilities and other inhomogenities in the ground. The code can use fully inhomogeneous terrain and facilities of arbitrary geometries. The only other code of this kind, developed by SANDIA Laboratories, does not allow frequencies below about 1 KHz, because of computational limitations. Our code allows operation down to dc. The code has helped model the effects of underground facilities on the low-frequency electromagnetic field propagating over the ground.

The different modules can serve different purposes: detecting, tracking, and characterizing magnetic signals, electromagnetic signals, and perturbations from different non-cooperative targets. Examples include tanks, trucks, and soldiers with rifles and handguns. It can also detect perturbations in low-frequency electromagnetic fields produced by metallic targets, such as underground facilities.