ADVANCED UNDERSEA TACTICAL COMMUNICATIONS TECHNIQUES

THERE IS AN INCREASING NEED FOR LONG RANGE (200KM) APPROXIMATELY 10 BPS RATE ACOUSTIC COMMUNICATION AT LOW BIT ERROR RATES IN THE COMMAND AND CONTROL OF ACOUSTIC SURVEILLANCE SYSTEM ELEMENTS, UNDERWATER VEHICLES AND SENSORS. SIMULATED FISH NOISE, CODED TONE AND MULTITONE CW SIGNALS HAVE BEEN USED WITH VARYING SUCCESS. ONLY THE M-ARY, MULTITONE, LONG BAND LOW FREQUENCY WAVEFORMS ARE PRACTICAL FOR LONG RANGE COMMUNICATIONS. HOWEVER, THE DEPENDENCE OF AMBIENT NOISE VS FREQUENCY, PROPAGATION LOSS VS RANGE, TRANSDUCER EFFICIENCY AND SIZE VS FREQUENCY AND TOTAL BANDWIDTH OCCUPIED MUST BE CONSIDERED IN THE ACOUSTIC LINK DESIGN. PHASE 1 OF THIS RESEARCH WILL PERFORM AND DOCUMENT THE TRADEOFFS THAT LEAD TO PRACTICAL COMMUNICATIONSSYSTEMS DESIGNS AND WILL PRODUCE A HANDBOOK OF MONOGRAPHS THAT WILL PERMIT THE USER TO SELECT THE SYSTEM VARIABLES THAT BEST SUIT THE APPLICATION AT HAND. THE RESULTS OF THISANALYSIS ARE THEN GOING TO BE APPLIED TO THE COMMAND AND CONTROL OF DISTRIBUTED SENSORS IN HOSTILE AREAS. PHASE 1 EFFORT WOULD PROVIDE THE FIRST DOCUMENTED ANALYSIS OF TRANSMITTER, POWER, AND VOLUME REQUIREMENTS NEEDED FOR LONG LIFE REMOTE SENSORS. PHASE 2 WILL FABRICATE A PROTOTYPE TO BE DEMONSTRATED AT SEA.