UTILIZATION OF ON-BOARD DIGITAL GEOMAGNETIC FIELD DATA AND ANCILLARY SOFTWARE TO OPTIMIZE MAGNETIC ASW OPERATIONS

THIS PROPOSAL SEEKS TO INVESTIGATE THE FEASIBILITY OF IMPROVING MAGNETIC ASW BY UTILIZING AN ON BOARD DIGITAL RECORD OF THE EARTH'S GEOMAGNETIC FIELD. MAGNETIC DETECTION TECHNIQUES FOR SUBMARINES REQUIRE SEPARATION OF THE SIGNATURE OF THE SUBMARINE FROM THE BACKGROUND FIELD. TESSERA PROPOSES TO DEVELOP A SYSTEM TO IMPROVE ANOMALY SEPARATION BY EMPLOYING EXISTING DIGITIZED GEOMAGNETIC FIELD DATA TO ACCOUNT FOR, AND SEPARATE FROM THE SIGNAL OF INTEREST, THE EFFECTS OF THE EARTH'S FIELD. AN ALGORITHM IS PROPOSED WHICH UTILIZES EXISTING MAGNETIC DATA TO LOCATE ANOMALOUS TARGETS BY DIGITAL FILTERING OF OBSERVED ASW DATA TOGETHER WITH PROPERLY CORRECTED GEOMAGNETIC FIELD DATA. THE COMBINATION OF THESE DATA ALLOW DESIGN OF AN OPTICAL SIGNAL EXTRACTION FILTER WHOSE WEIGHTS VARY FROM POSITION TO POSITION DEPENDING UPON THE NATURE OF THE GEOMAGNETIC FIELD. TARGET DETECTION IS ENHANCED BY MEANS OF AN OPTIMIZED DIGITAL ALGORITHM EMPLYING BOTH THE EXISTING DATA BASE AND THE UPDATED MAGNETIC DATA OBSERVED BY THE ASW AIRCRAFT.