Application of magnetic signature processing to magnetic center pinpointing in marine vehicles

This work the improves measuring techniques and predictive capabilities in naval magnetic silencing. Enhanced investigations of measuring procedures, which analyze external magnetic fields, can lead to concepts and methods for controlling those fields in marine vehicles. This necessitates the development and use of improved analysis and imaging techniques to satisfy demanding requirements in magnetic silencing. This report is aimed at investigation of high-precision measurement techniques to be used in the design of a land- or marine-based magnetic test range. Modeling of the dynamic measuring procedures receives our special attention. We use standard field sources and sense coils to simulate magnetic signatures of marine vehicles. A standard field source consists of an array of suitably placed circular coils that carry stabilized currents. Sense coils are cylindrical in shape and detect the magnetic signature (magnetic flux) from the standard source when the source and sensors are moved relative to one another. These signatures are analyzed further for the identification of a magnetic center with our original integral transforms. We simulate four different multipole magnetic sources to calculate magnetic signatures. The standard magnetic field source, which is used in the experiment, includes coils with external diameter of 0.1 m and length 0.02 m. The magnetic moment of each coil is 10 A/spl middot/m/sup 2/. The estimated error of the magnetic center location with the magnetic signature analysis does not exceed 10% for the 61-point grid. The measurement procedure illustrated could be used to determine the locations of major on-board magnetic sources and identify how to compensate them.