Abstract: An apparatus and method for electronically controlling ordnance fuzes by sensing magnetic fields proximate the ordnance via a magnetic field sensor. The sensor is preferably a giant magnetoresistance detector. For spinning ordnance, in-flight cumulative range can be calculated by counting turns of the spinning ordnance. Ordnance may be armed a pre-determined time after exit of the ordnance from a weapon firing the ordnance as determined by the magnetic field sensor. The invention is also of a giant magnetoresistance sensor and method for making same and an apparatus for and method of sensing angular velocity for spinning ordnance.

Abstract: An apparatus and method for detecting defects in electrically conductive materials. A detection method and apparatus are provided for using applied magnetic fields to induce magnetic fields in the material under test, and then directly detecting changes in the induced magnetic field attributable to corrosion, cracks, flaws, or anomalies in the material under test. The invention features the use of one or more giant magnetoresistance sensors to detect directly the changes in the induced magnetic field, which changes provoke a response in the giant magnetoresistance sensors in the form of a change in resistance signal. The apparatus may be configured in various ways, including absolute field detection and differential field detection configurations, with either passive or active field compensation, and single sensor or multiple sensor arrays. A plurality of giant magnetoresistance sensors may be disposed upon a single substrate, or on multiple substrates.