Abstract: Methods are provided to package and deploy a marine vibrator for use in connection with marine seismic surveys. Marine vibrators are provided with a number of buoyancy configurations with corresponding techniques for controlling the submergence depth of the marine vibrators. An exemplary marine vibrator comprises a positively buoyant hydrodynamic tow body, comprising: a low frequency electro-acoustic projector; a power electronics system; a control-monitoring electronics system; and a pressure compensation system, wherein the hydrodynamic tow body comprises one or more active control surfaces to adjust a submergence depth and a roll attitude of the hydrodynamic tow body. Additional embodiments employ a free-flooding, load-bearing frame with positive or negative buoyancy.

Abstract: Systems and methods and described herein that can enable accurate forecasting of ship motions and the useful displaying of such forecasts to users. In general, the ship motion forecasting systems and methods provide users with graphical indication of ship motion forecasts in the form of operational period indicators. These operational period indicators are generated such that the ship motion forecasts under at least one motion threshold for a time period exceeding a time threshold are indicated in a first way, while ship motion forecasts not under the at least one motion threshold for the time period exceeding the time threshold are indicated in a second way, different from the first way. This can facilitate the quick determination of operational status by a user and thus allow a user to quickly ascertain when conditions are likely to be such that certain ship operations can be safely performed.

Abstract: Systems and methods for ship motion forecasting are described herein. These ship motion forecasting systems can enable accurate real-time forecasting of waves and resultant vessel motions, and the useful displaying of such forecasts to users. In general, the ship motion forecasting systems and methods provide users with useful indications of ship motion forecasts by generating scrolling graphical representations of the ship motion forecasts. For example, the systems can be implemented to display on a first window portion a plurality of graphical representations of ship motion forecasts generated over a plurality of forecast cycles, where the graphical representations of new ship motion forecasts are added as generated, and where the graphical representations of previously generated ship motion forecasts are scrolled as new ship motion forecasts are added.

Abstract: Ship motion forecasting systems and methods are described herein that can enable accurate real-time forecasting of ocean waves and resultant ship motions. Such systems and methods can be used to improve the efficiency and safety of a variety of ship operations, including the moving of cargo between ships at sea. In general, the systems and methods transmit radar signals from multiple radars, and those radar signals from the multiple radars are reflected off the surface of a body of water. The reflected radar signals are received, and radar data is generated from the received radar signals. The radar data is used to generate ocean wave components, which represent the amplitude and phase of a multitude of individual waves that together can describe the surface of the ocean. These ocean wave components are then used generate ship motion forecasts, which can then be presented to one or more users.

Abstract: Methods are provided to package and deploy a marine vibrator for use in connection with marine seismic surveys. Marine vibrators are provided with a number of buoyancy configurations with corresponding techniques for controlling the submergence depth of the marine vibrators. An exemplary marine vibrator comprises a positively buoyant hydrodynamic tow body, comprising: a low frequency electro-acoustic projector; a power electronics system; a control-monitoring electronics system; and a pressure compensation system, wherein the hydrodynamic tow body comprises one or more active control surfaces to adjust a submergence depth and a roll attitude of the hydrodynamic tow body. Additional embodiments employ a free-flooding, load-bearing frame with positive or negative buoyancy.

Abstract: A coherent sound source is provided for marine seismic surveys. An underwater sound projector for producing time-harmonic waveforms comprises two pistons positioned on either side of an electro-magnetic force generator substantially having mechanical and magnetic symmetry about its geometric center thereby creating a virtual node to substantially cancel reaction loads that occur when the pistons are actuated. The underwater sound projector optionally also includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and change the depth and roll when it is configured as tow body. A plurality of underwater sound projectors can be configured in an array.

Abstract: A coherent sound source is provided for marine seismic surveys. An exemplary underwater sound projector comprises a plurality of pistons actuated by an electromagnetic force generator having components comprising a stator, armatures, electrical coils, and permanent magnets. The pistons and the components are arranged to create mechanical and magnetic symmetry about a geometric center of the projector to reduce reaction loads that occur when the pistons are actuated. The stator and the armatures have magnetic poles that employ a tapered geometry. The projector optionally includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and/or change the depth and roll when the projector is configured as a tow body. A plurality of such projectors can be configured in an array.

Abstract: Techniques are provided for sparse array RF imaging for surveillance applications. The present invention enables object image identification using a sparsely populated array of distributed radio nodes deployed and operated as a radar detection, tracking and identification application. Three-dimensional object images are formed, from which estimates of extent and shape can be extracted for objects that are detected in the vicinity of the deployed radar array. In addition, techniques are provided for the identification and/or classification of vehicles, humans and fauna through feature extraction from the formed three-dimensional images.

Abstract: Low cost miniature vector sensors are provided. An acoustic vector sensor is provided that comprises at least one accelerometer to measure at least one component of acoustic particle acceleration, wherein the at least one accelerometer has a resonant frequency within a measurement band of the acoustic vector sensor. In addition, a method is disclosed for measuring an acoustic signal. The method comprises the steps of configuring an array of acoustic vector sensors comprised of at least one accelerometer to measure at least one component of acoustic particle acceleration; operating the at least one accelerometer at a resonant frequency within a measurement band of the acoustic vector sensor; and generating a voltage using one or more of the acoustic vector sensors representative of the acoustic signal as the acoustic signal propagates past the array. The voltage optionally indicates a bearing of the acoustic signal.

Abstract: A cantilever beam accelerometer design is disclosed that obviates the need of attaching electrical leads directly to the piezoelectric plates. According to one aspect of the invention, two identical proof-masses are positioned on top of each piezoelectric plate in a symmetrical fashion. In advance of attaching the masses to the plates, electrical leads are attached to the masses by some suitable technique such as soldering. Each proof-mass is positioned on its respective piezoelectric plate as close to the free-end of the beam as practical, to keep the size of the mass reasonably small. The disclosed concept is useful for both series and parallel configurations of the piezoelectric plates, wherein the polarization vectors are in opposite directions for two plates connected in series and the polarization vectors are in the same direction for two plates connected in parallel.

Abstract: A dual cantilever beam relaxor-based piezoelectric single crystal accelerometer is provided. A flexural sensing structure is provided that employs at least two piezoelectric cantilever beams having their longitudinal axes disposed in a substantially parallel arrangement with each beam containing at least one relaxor-based single crystal transduction element having its polarization axis substantially perpendicular to the longitudinal axis of the beam. One end is mounted to a rigid base and the other end can be mounted to a seismic proof-mass or can be free, wherein the base is subjected to dynamic excitation from either mechanical or acoustical origin. The flexible sensing structure can optionally be encapsulated in a viscoelastic material having a mechanical compliance and loss that is substantially greater than that of the flexible sensing structure.

Abstract: Techniques are provided for sparse array RF imaging for surveillance applications. The present invention enables object image identification using a sparsely populated array of distributed radio nodes deployed and operated as a radar detection, tracking and identification application. Three-dimensional object images are formed, from which estimates of extent and shape can be extracted for objects that are detected in the vicinity of the deployed radar array. In addition, techniques are provided for the identification and/or classification of vehicles, humans and fauna through feature extraction from the formed three-dimensional images.

Abstract: Low cost miniature vector sensors are provided. An acoustic vector sensor is provided that comprises at least one accelerometer to measure at least one component of acoustic particle acceleration, wherein the at least one accelerometer has a resonant frequency within a measurement band of the acoustic vector sensor. In addition, a method is disclosed for measuring an acoustic signal. The method comprises the steps of configuring an array of acoustic vector sensors comprised of at least one accelerometer to measure at least one component of acoustic particle acceleration; operating the at least one accelerometer at a resonant frequency within a measurement band of the acoustic vector sensor; and generating a voltage using one or more of the acoustic vector sensors representative of the acoustic signal as the acoustic signal propagates past the array. The voltage optionally indicates a bearing of the acoustic signal.