Magnetic Sensors for Navigation and Security Applications

Summary form only for tutorial. Magnetic sensors are key elements in many security, military, and navigation systems. Fast development of new sensor types such as AMR (Anisotropic MagnetoResistors), GMR (Giant Magneto-Resistance), SDT (Spin- Dependent Tunelling) and GMI (Giant Magneto-Impedance) brings new opportunities; but not all new is better. The purpose of this tutorial is to critically review the principles and properties of modern magnetic sensors and show how they presently are employed in navigation and security applications and what is their future potential. The emphasis will be given for mine and UXO (Unexploded Ordnance) location. 1. Principles and techniques: - principles of DC magnetic sensors suitable for security applications (incl. AMR, GMR, SDT and miniaturized resonant and fluxgate sensors) - eddy-current methods - induction magnetometers - electromagnetic methods including ELF and Ground Penetrating Radar - imaging techniques, signal processing, recognition - gradiometric techniques, sensor fusion - calibration and error corrections 2. Applications - Mine detection - UXO location - Detection and recognition of vehicles (incl. submersible) - Detection frames and other sensors for border security - Magnetic labels and anti-theft systems - Navigation systems - Magnetic tracking - Distance measurement - Distributed sensors and sensor areas