Sanders Associates Limited

Bae Systems Information and Electronic Systems Integration Inc.

Lockheed Martin Corporation

Harvey C Woodsum

Charles Carey

Richard Jensen

Albin A Hastbacka

Richard A Jensen

Charles A Carey

Richard A Maloon

This invention is a steerable thermoacoustic array system for directing information between an object that is above the surface of the water and a sound detector that is beneath the surface of the water. The foregoing system comprises a laser or particle accelerator that is located above the water's surface. The laser or particle beam produces a light beam or particle beam which contains information that is moved along a small layer of water at the air/water interface at a speed equal to the speed of sound in water divided by the steering angle of the laser so that the light beam or particle beam is absorbed by the water causing the water to expand and produce a series of acousitic Braves that constructively interfere with each other and travel towards the sound detector.

Steerable thermoacoustic array

This invention is a thermoacoustic system for communicating between an airborne or spaceborne vehicle and a sound detector that is located aboard an object beneath the surface of the water. The foregoing system comprises a laser or particle accelerator that is located aboard an airborne or spaceborne vehicle. The laser produces a light beam whose amplitude is subsequently modulated or whose pulses are varied in time. A particle accelerator would produce a pulsed particle beam that varies in time. These modulated or varied pulses are focused or deflected to a small layer of water at the air/water interface so that the beam will be absorbed by the water causing the water to produce an acoustic signal that will propagate to the sound detector.

Thermoacoustic communications system

This invention is a thermoacoustic sonar system for detecting a target that is located at or beneath the surface of the water. The foregoing system comprises a laser or particle accelerator that is located above the water and a plurality of passive receivers that are located on or above the water. The laser produces a light beam whose amplitude is subsequently modulated or whose pulses are varied in time. A particle accelerator would produce a pulsed particle beam that varies in time. These modulated or varied pulses are focused or deflected to a small layer of water at the air/water interface so that the beam will be absorbed by the water causing the water to produce an acoustic signal that may propagate to a target where the acoustic signal will be reflected and possibly detected by one or more passive receivers.

Thermoacoustic bi-static sonar system

Disclosed and claimed in a communications system which permits the simultaneous reception and jamming of a transmitted radio frequency signal. This is accomplished by sampling the signal for a minimal period with the jammer off, operating the jammer for a much longer time than was previously thought possible, then using the coefficients output from a linear prediction filter to provide an estimate signal from the transmitted signal while the jammer transmitter is on. The coefficients may be smoothed by averaging over several segments. In addition, if the transmitted signal was a voice signal, voiced-unvoiced decision logic may be used to improve the system's performance.

Autoregressive peek-through comjammer and method

The invention concerns an application of linear system parameter estimation techniques to finite amplitude sonar devices, to extract fine grained angular position information about echo sources. The invention makes use of the fact that the waveform return by a reflecting object within the sonar's beam varies according to its relative angular position from the receiver, and a discovery that this variation may be fit to a linear system model using autoregressive estimation theory to extract the nature of the variation. In all cases, the information is extracted without the mechanical or electrical steering of the sonar transmitting beam.

Virtually steerable parametric acoustic array

In a digital communications system, one of two tones is selected for each bit, a first tone for a '0' and a second tone for a '1'; the tones are unique for each bit. The tones for all of the bits of a byte are sent simultaneously, in a burst or pulse. At the receiver, a parametric model-based spectrum analysis is performed to find the constituent frequencies which produced the composite spectrum. This spectrum analysis uses autoregressive parameter estimation techniques to determine the most likely combination of frequency components which would have generated the composite spectrum. The combination of frequency components so found is then decoded to yield the corresponding bit values represented by those frequencies. The use of autoregressive spectral analysis techniques to recover the frequency components in the composite signal provides both bandwidth compression (by virtue of increased resolution) and faster signalling rates in transmitting just such signals. Two methods are known for deriving spectral information from coefficients obtained through autoregressive spectral analysis; correspondingly, two embodiments are shown herein, for exploiting the differing properties of each such method. One method derives only the frequencies of the spectral components, while the second method also provides the pulse widths of the transmitted signals.

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Nashua, NH, United States of America

Harvey C Woodsum