SHORT-RANGE UNDERWATER COMMUNICATIONS

THERE ARE MANY SITUATIONS IN WHICH NAVAL FORCES REQUIRE THE ABILITY TO COMMUNICATE OVER SHORT RANGES UNDERWATER. THESE COMMUNICATIONS MUST BE EFFECTED THROUGH A CHANNEL WHICH EXHIBITS SEVERE MULTIPATH AND REVERBERATION. BACKGROUND INTERFERENCE CAN ARRIVE FROM GREAT DISTANCES IN THE OCEAN, DISRUPTING UNDERWATER SOUND SYSTEMS. IN ADDITION, IT IS OFTEN DESIRED TO KEEP THE COMMUNICATIONS COVERT; THIS REQUIRES THAT MINIMUM POWER BE UTILIZED AND THAT ALL STEPS POSSIBLE BE TAKEN TO HIDE THE COMMUNICATIONS. RADIO TECHNIQUES EXIST WHICH CAN SUPPRESS INTERFERENCE AND ENABLE THE IMPLEMENTATION OF ANTIMULTIPATH TECHNIQUES. THE DEVELOPMENT PROPOSED HEREIN WOULD EXPLOIT WELLDEVELOPED TECHNIQUES FROM THE RADIO-COMMUNICATION FIELD TO PROVIDE FOR RELIABLE UNDERWATER COMMUNICATIONS USING SOUND; AND ENABLE COVERT COMMUNICATIONS IF REQUIRED.