APPLICATION OF THE AIRBORNE ELECTROMAGNETIC METHOD TO SUBMARINE DETECTION

GEOPHEX, LTD. PROPOSES TO DEVELOP AN AIRBORNE ELECTROMAGNETIC (AEM) SYSTEM DEDICATED TO THE DETECTION OF SUBMARINES IN THE OCEAN (TOPIC NO. N87-22, THE DOD SBIR PROGRAM, 1987). THE AEM METHOD HAS RECENTLY EMERGED AS A VIABLE TECHNIQUE FOR AIRBORNE CHARTING OF WATER DEPTH (IN EXCESS OF PERHAPS 100 M), WATER CONDUCTIVITY (THUS, SALINITY AND TEMPERATURE VARIATIONS), AND BOTTOM SEDIMENT CONDUCTIVITY (THUS, DENSITY, POROSITY, AND SEDIMENT TYPES). DURING TWO RECENT EXPERIMENTAL AEM FLIGHTS FOR BATHYMETRIC MISSIONS, THE METHOD HAS PROVED TO BE ABLE TO PROFILE MINUTE CHANGES IN WATER CONDUCTIVITY. THE ABILITY OF THE AEM METHOD TO PROFILE WATER CONDUCTIVITY LEADS US TO BELIEVE THAT THE METHOD CAN BE ADAPTED TO A SUBMARINE DETECTION MISSION. SPECIFICALLY, IT SHOULD BE ABLE TO LOCATE THE DISTURBANCE PLUME WHICH TAILS BEHIND SUBMARINES. THIS CONDUCTIVITY DISTURBANCE PLUME, WHICH MAY BE OF CONSIDERABLE LENGTH, CAN BE AN EASILY TRACKABLE TARGET FOR AN AEM SURVEY. IN THIS PROPOSAL, WE SHOW THEORETICAL STUDIES AND EXPERIMENTAL RESULTS PERFORMED BY GEOPHEX TO SUPPORT OUR CLAIM.