Magnetic Scalar Triangulation and Ranging system for autonomous underwater vehicle based detection, localization and classification of magnetic mines

This paper reports progress toward implementation of a novel magnetic gradiometer concept that, with support from the Office of Naval Research, is being developed for detection, localization and classification (DLC) of ferrous mines in very shallow water/surf zone (VSW/SZ) environments. The gradiometer\´s design allows development of an unique magnetic gradient tensor-contraction-based "Scalar Triangulation and Ranging (STAR)" method for processing magnetic target signatures. Previously reported work has resulted in development of a prototype STAR-based magnetic target-homing system for underwater bottom vehicle (UBV)-type AUVs. Experimental field test results and computer simulations for a linear, two-dimensional "UBV-STAR" gradiometer indicate that guidance algorithms based on the STAR method would provide a very efficient modality for autonomously homing in on underwater and buried mines. Current efforts include development of an advanced three-dimensional STAR gradiometer concept that would allow autonomous, free-swimming sensing platforms to very efficiently home in on the magnetic signatures of underwater and buried mines. The results of the research and development effort demonstrate that the magnetic STAR concept\´s approach to gradiometer design and its method of processing magnetic signatures can provide free-swimming AUVs and/or Navy Divers with uniquely practical and effective modalities for real-time, fully autonomous DLC of magnetic mines and for homing in on magnetic targets.