United States of America As Represented by the Administrator of Nasa

The United States of America As Represented by the Administrator of the

Qamar A Shams

Allan J Zuckerwar

Christopher L Fox, Legal Representative

Robert L Fox

Albert L Dimarcantonio

Melanie L Fox, Legal Representative

Stanley E Woodard

Sidney G Allison

John J Chapman

Melanie L Fox Chattin, Legal Representative

William T Powers

Robert G Bryant

Bryant Douglas Taylor

John F Sutton

Robert W Moses

John W Stoughton

Michael J Logan

Neil C Coffey

Tianshu Liu

James K Adams

Howard K Knight

Walter C Babel, Iii

Richard L Chattin

John C Ingham

Sean A Laughter

Theodore R Kuhn, Iii

An extremely low frequency hydrophone includes a housing forming an interior space comprising a backchamber. The housing includes an opening to the interior space, and a side of the housing comprises a diaphragm plate. A backplate is disposed inside the housing adjacent the diaphragm plate, and an electronics unit including a preamplifier is disposed in the interior space. The hydrophone further includes dielectric liquid substantially filling the interior space. A passageway permits inert gas to be introduced into the dielectric liquid in the interior space of the housing.

Extreme low frequency microphone/hydrophone for exploration of oceanic and atmospheric dynamics

Various embodiments may provide an airborne system for measuring meteorological parameters, including a high altitude unmanned aerial vehicle (UAV) formed completely or partially of closed-cell polyurethane foam. In various embodiments, the UAV may include extendable wings configured to extend and retract as the UAV climbs and descends to different altitude levels. In various embodiments, the UAV may include one or more infrasonic sensors and wind screening configured to measure one or more meteorological parameters, such as wind shear, seismic waves, magnetic storms, magnetohydrodynamic waves, severe weather, tornadoes, hurricanes, meteors, and lighting. The infrasonic sensors may be configured to determine wind shear at the local and regional level. In various embodiments, other meteorological sensors may also be included in/on the UAV in addition to the infrasonic sensors.

High altitude UAV for monitoring meteorological parameters

A method for recognizing infrasound events includes detecting infrasonic source using one or more microphone arrays each having three equally-spaced infrasound microphones. The method includes identifying, via a data acquisition system (DAS), a level of coherence of the detected infrasonic acoustic signals from each possible pair of microphones and recognizing the infrasound source using the coherence and a time history of the detected signals. The method may include estimating source properties via the DAS, including a magnitude, azimuth angle, and elevation angle, and executing a control action in response to the estimated properties. A system includes the array and the DAS. The array may be positioned above or below ground, and may be connected to one or more aircraft in some embodiments.

Adaptive algorithm and software for recognition of ground-based, airborne, underground, and underwater low frequency events

Systems and methods are disclosed for passively detecting air turbulence using one or more infrasonic sensors mounted on an aircraft. The system may include one or more infrasonic sensors that are mounted on the aircraft and configured to detect infrasound. The system may also include a processor configured to receive output signals from the one or more infrasonic sensors and detect air turbulence away from the aircraft based on the output signals received from the one or more infrasonic sensors. The detected air turbulence may include natural or man-made turbulence including wake turbulence, clear air turbulence, mountain waves, or events such as a rocket launch.

System and method for onboard wake and clear air turbulence avoidance

An infrasonic stethoscope for monitoring physiological processes of a patient includes a microphone capable of detecting acoustic signals in the audible frequency bandwidth and in the infrasonic bandwidth (0.03 to 1000 Hertz), a body coupler attached to the body at a first opening in the microphone, a flexible tube attached to the body at a second opening in the microphone, and an earpiece attached to the flexible tube. The body coupler is capable of engagement with a patient to transmit sounds from the person, to the microphone and then to the earpiece.

Infrasonic stethoscope for monitoring physiological processes

A magnetometer configured to measure low field strength magnetic fields is provided. Certain embodiments of the magnetometer include a cylindrical coil assembly having a variable permeability core and terminals disposed at both ends. A current source circuit may be operably connected to the terminals and configured to apply a voltage controlled current across the terminals. A voltage readout circuit may be operably connected to the terminals and configured to measure a voltage across the terminals due to the applied current from the current source. An inductance of the coil assembly directly varies as an ambient magnetic field strength varies a permeability of the variable permeability core, and a voltage across the terminals varies directly with the inductance such that the measured voltage across the terminals is a direct measure of the ambient magnetic field strength.

Variable permeability magnetometer systems and methods for aerospace applications

A wake vortex avoidance system includes a microphone array configured to detect low frequency sounds. A signal processor determines a geometric mean coherence based on the detected low frequency sounds. A display displays wake vortices based on the determined geometric mean coherence.

Wake vortex avoidance system and method

The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

Extreme low frequency acoustic measurement system

An airfoil system includes an airfoil body and at least one flexible strip. The airfoil body has a top surface and a bottom surface, a chord length, a span, and a maximum thickness. Each flexible strip is attached along at least one edge thereof to either the top or bottom surface of the airfoil body. The flexible strip has a spanwise length that is a function of the airfoil body's span, a chordwise width that is a function of the airfoil body's chord length, and a thickness that is a function of the airfoil body's maximum thickness.

Airfoil system for cruising flight

A windscreen is configured for measuring outdoor infrasonic sound. The windscreen includes a container and a microphone. The container defines a chamber. The microphone is disposed in the chamber and can be operatively supported by the floor. The microphone is configured for detecting infrasonic sound. The container is advantageously formed from material that exhibits an acoustic impedance of between 0 and approximately 3150 times the acoustic impedance of air. A reflector plate may be disposed in the container. The reflector plate operatively can support the microphone and provides a doubling effect of infrasonic pressure at the microphone.

Sub-surface windscreen for outdoor measurement of infrasound

A self-contained avionics sensing and flight control system is provided for an unmanned aerial vehicle (UAV). The system includes sensors for sensing flight control parameters and surveillance parameters, and a Global Positioning System (GPS) receiver. Flight control parameters and location signals are processed to generate flight control signals. A Field Programmable Gate Array (FPGA) is configured to provide a look-up table storing sets of values with each set being associated with a servo mechanism mounted on the UAV and with each value in each set indicating a unique duty cycle for the servo mechanism associated therewith. Each value in each set is further indexed to a bit position indicative of a unique percentage of a maximum duty cycle for the servo mechanism associated therewith. The FPGA is further configured to provide a plurality of pulse width modulation (PWM) generators coupled to the look-up table. Each PWM generator is associated with and adapted to be coupled to one of the servo mechanisms.

Self-contained avionics sensing and flight control system for small unmanned aerial vehicle

A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

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Yorktown, VA, United States of America

Qamar A Shams