UNDERWATER DIGITAL ACOUSTIC TELEMETRY SYSTEM

THERE IS A NEED FOR A HIGH DATA RATE UNDERWATER ACOUSTIC TELEMETRY SYSTEM WHICH WILL OPERATE AT A HIGH RATE OF DATA OR VOICE TRANSMISSION IN A REVERBERENT, MULTIPATH ENVIRONMENT. THIS PROPOSAL DESCRIBES A SYSTEM CONCEPT WHICH, IF SUCCESSFULLY IMPLEMENTED, WILL ALLOW TRANSMISSION OF DATA AT RATES UP TO 4800 BITS PER SECOND OVER A HIGHLY REVERBERENT, SHALLOW UNDERWATER PATH. THE PROPOSED TECHNIQUE WILL MAKE USE OF SPREAD SPECTRUM AND DIRECTIONAL TRANSMISSION TECHNIQUES TO OVERCOME THE DEGRADING EFFECTS OF SIGNAL DISTORTION CAUSED BY ACOUSTIC MULTIPATH NORMALLY ENCOUNTERED IN THIS TYPE OF OPERATING ENVIRONMENT. INTERNAL DATA PROCESSING WILL ALLOW INTERFACING OF THE ACOUSTIC LINK WITH MOORED INSTRUMENTS, ANALOG SENSORS, OR VOICE INPUT IN A MANNER WHICH WILL ALLOW REMOTE RECOVERY OF DATA IN A TIMELY, RELIABLE MANNER. PROPOSED PHASE I RESEARCH INCLUDES THE FIELD TESTING, AND VERIFICATION OF SYSTEM CONCEPTS WHICH WILL LEAD TO SPECIFICATIONS AND SYSTEM DEVELOPMENT TO BE CONDUCTED AS PART OF PHASE II.