Generalized magnetic gradient contraction based method for detection, localization and discrimination of underwater mines and unexploded ordnance

We report significant progress toward full development of a unique magnetic-gradient-tensor-based "scalar triangulation and ranging (STAR)" method for detection, localization and classification (DLC) of magnetic targets. The STAR method converts magnetic tensors to rotationally invariant scalar parameters that are virtually unaffected by the effects of sensing platform motion. Thus, the STAR method is particularly appropriate for magnetic target DLC using highly mobile sensing platforms such as autonomous underwater vehicles (AUV). Prior work has resulted in development of a two-dimensional (2D) magnetic target-homing concept for fully autonomous localization of mines using crawler-type AUVs. However, the simple 2D STAR approach cannot effectively discriminate between magnetic clutter and mine-like target signatures. Improved, 3D simulations demonstrate that the STAR concept can be applied to measurements of the vector positions and dipole signatures of magnetic objects. The new results indicate that an improved STAR system will provide an enhanced capability for discrimination between magnetic clutter and real targets such as magnetic mines and Unexploded Ordnance (UXO). Consequently, further development of the advanced STAR concept will provide high-mobility autonomous sensing platforms (such as AUVs and man-portable systems) with a uniquely effective modality for DLC of magnetic mines and UXO