USA As Represented by Secretary of the Navy

Maurice J Griffin

Fred Nussbaum

Gerald T Stevens

Ira B Cohen

Glenn S Sugawara

A sonar array comprising a support structure, an acoustic projector attached to the support structure, and a plurality of directional hydrophones attached to the support structure and arranged so as to surround the acoustic projector. The directional hydrophones are equidistantly spaced about the acoustic projector. In one embodiment, the array includes means attached to the support structure that allows the support structure to be connected to a device that effects course steering of the sonar array.

Sonar tracking array

A sonar sensor array having a multi-layer tiling arrangement for the indiual elements that increases surface area available for each element while maintaining the inter-element spacing required to avoid spatial aliasing when the received signals are combined to form a sonar beam. The array comprises outer and inner arrays of transducer elements for converting an acoustic signal to an electrical response. The transducer elements of the outer array are positioned such than a grid of isolation spaces separates each of the transducer elements. The transducer elements of the inner array are also positioned such that a grid of isolation spaces separates each one of the transducer elements. The electrical response generated by the transducer elements of the inner and outer arrays are coupled to a beamformer which processes the responses to produce an output signal.

Multi-layer tiled array

A sonar array uses multiple acoustically transparent layers. One layer is a lanar array of acoustic sensors that is substantially acoustically transparent. Another layer is an acoustically transparent wiring assembly that provides electrical connection to each acoustic sensor. A third acoustically transparent layer is a planar array of signal processing circuits coupled to the wiring assembly for processing electrical signals generated by the acoustic sensors. Each signal processing circuit resides within an area that is in geometric correspondence with a respective one acoustic sensor. Each signal processing circuit can include a preamplifier, an analog-to-digital converter and a digital multiplexer.

Multi-layer acoustically transparent sonar array

A system for storing an arbitrary waveform on non-volatile random access ory (NVRAM) device and generating an analog signal using the NVRAM device. A central processing unit is used to synthesize an arbitrary waveform and create a digital representation of the waveform and transfer the digital representation to a microprocessor which, in turn, writes the digital data into an NVRAM device which has been mapped into a portion of the microprocessor address space. The NVRAM device is removed address space and placed into an independent waveform generation unit. In the waveform generation unit, an address clock provides an address timing signal and a cycle clock provides a transmit signal. Both signals are applied to an address generator. When both signals are present, the address generator generates and transmits to the NVRAM device a new address for each cycle of the address timing signal. In response to each new address generated, the NVRAM devices provides a digital output which is applied to a digital to analog converter. The converter produces a continuous analog output which is smoothed by a filter to produce the arbitrary waveform.

Arbitrary waveform generator

An acoustic receiving array synthesized using a single stationary receiving lement and a rotating target. Echoes from a highly repeatable transmit pulse are digitized and recorded as the target is rotated. Controlled geometry and essentially stationary channel characteristics eliminate the need for adaptive beamforming techniques. Subsequent to acquisition of the desired data set conventional time delay beam-forming and steering techniques for multi-dimensional arrays are used to focus the array at desired locations. Energy level in a time gate is computed and recorded for each image location. Finally a raster image is generated using the thresholded energy levels.

Growing community of inventors

Tiverton, RI, United States of America

Maurice J Griffin