Acoustic telemetry for underwater control

The need for a wireless, high-security, high-capacity, highly reliable control system for undersea operations increases as the offshore oil industry begins production in deeper waters. Acoustic telemetry provides a practical method of remote subsea control. Through the use of frequency and time diversity, an FSK modulation scheme can provide an acoustic telemetry system capable of operation over long horizontal ranges (3 nautical miles or more) in a severe multipath and noise environment. This paper describes the design and test of an acoustic telemetry system capable of transmitting and receiving 128 unique commands at a signaling rate of 40 bits per second. Test results have demonstrated a greater-than-94 percent probability of message detection with zero false operations or message errors in 40 hours of operation.