DOLPHIN, An Emerging Technology For Undersea Acoustics

Acoustics enable many core undersea capabilities. Where radio waves do not propagate well, and light is absorbed quickly, acoustic signals help us map, see, locate and communicate. The many products and technologies that employ acoustics all depend upon signal processing, thus new processing approaches can impact many applications. QinetiQ and its partner Optimal Systems Laboratory (OSL) have developed DOLPHIN™ - a patented method using analog cancellation that eliminates receiver saturation and enables simultaneous transmit and receive, resulting in full duplex communications signals. Since the beginning of acoustic communications, the state of the art technology has been limited to half-duplex signals: transmit with the receiver off and then turn the transmitter off and receiver on and wait to receive. Half duplex has been required because the direct transmission at the source saturates the receiver electronics if both the transmitter and receiver are enabled simultaneously. On the other hand, the new DOLPHIN technology enables true full-duplex acoustic telemetry. It cancels the transmit signal at the receiver in real-time. This eliminates receiver self-signal saturation and enables simultaneous transmitting and receiving on the same frequency, with collocated transducers. The DOLPHIN technology is frequency and range independent - thus yielding flexible new approaches to underwater communications. This paper reviews the underlying DOLPHIN technology, initial field trials, recent simulation results and a preliminary open protocol concept. It concludes with a vision for future concepts of operations.