A method of determining a measure of wave speed intensity in a fluid conduit uses ultrasound measurements to determine the conduit diameter, as a function of time, at a longitudinal position of the conduit, and to determine a measure of fluid velocity, as a function of time, in a volume element at said longitudinal position of the conduit. The ultrasound measurement to determine the measure of fluid velocity is effected by decorrelation of scattering objects within the fluid flow in successive frames sampling the volume element. A wave speed may be determined from a ratio of the change in fluid velocity at the longitudinal position as a function of time and the change in a logarithmic function of the conduit diameter as a function of time. A measure of wave intensity may be determined as a function of change in determined conduit diameter and corresponding change in fluid velocity.

Disclosed is a tidal current meter that measures the velocity of a tidal current. The tidal current meter includes an oscillator, a calculation section, a depression angle setup section, and a drive section. The oscillator is capable of transmitting an ultrasonic wave into water and receiving the reflection of the transmitted ultrasonic wave. The calculation section calculates the velocity in accordance with the Doppler shift frequency of the reflection received by the oscillator. The depression angle setup section sets a depression angle, that is, the angle formed by the transmission direction of the ultrasonic wave and a horizontal plane. The drive section drives the oscillator in such a manner as to transmit the ultrasonic wave and receive the reflection of the transmitted ultrasonic wave at the depression angle set by the depression angle setup section.

An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes.

Systems and methods for adding buoyancy to an object are described herein. A buoyant material may be enclosed inside a flexible container, heated, and inserted into a free flooded cavity inside the object. The flexible container may then be formed to the shape of the cavity. After the flexible container is formed to the shape of the cavity, the flexible container may be cooled. The flexible container may hold a pre-determined amount of the syntactic material that provides a fixed amount of buoyancy. According to another aspect, systems and methods for packing a vehicle are described herein. In some embodiments, a buoyant material may be molded into the shape of a hull of a vehicle, and a plurality of cutouts may be extracted from the buoyant material which are specifically designed to incorporate one or more instruments.

Systems and methods are disclosed herein for a pressure tolerant energy system. The pressure tolerant energy system may comprise a pressure tolerant cavity and an energy system enclosed in the pressure tolerant cavity configured to provide electrical power to the vehicle. The energy system may include one or more battery cells and a pressure tolerant, programmable management circuit. The pressure tolerant cavity may be filled with an electrically-inert liquid, such as mineral oil. In some embodiments, the electrically-inert liquid may be kept at a positive pressure relative to a pressure external to the pressure tolerant cavity. The energy system may further comprise a pressure venting system configured to maintain the pressure inside the pressure tolerant cavity within a range of pressures. The pressure tolerant cavity may be sealed to prevent water ingress.

An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes.

Systems and methods are disclosed herein for a pressure tolerant energy system. The pressure tolerant energy system may comprise a pressure tolerant cavity and an energy system enclosed in the pressure tolerant cavity configured to provide electrical power to the vehicle. The energy system may include one or more battery cells and a pressure tolerant, programmable management circuit. The pressure tolerant cavity may be filled with an electrically-inert liquid, such as mineral oil. In some embodiments, the electrically-inert liquid may be kept at a positive pressure relative to a pressure external to the pressure tolerant cavity. The energy system may further comprise a pressure venting system configured to maintain the pressure inside the pressure tolerant cavity within a range of pressures. The pressure tolerant cavity may be sealed to prevent water ingress.

An object detecting apparatus that detects an object using a distance measuring sensor and is mounted in a moving body includes a position calculator that calculates a position of the object relative to the moving body, a speed detector that detects a speed of the moving body, a displacement calculator that calculates an distance moved by the moving body, a relative speed calculator that calculates a relative speed between the moving body and the object, a first determiner that determines whether a position calculation in the position calculator is possible, a second determiner that determines whether the moved distance calculation by the displacement calculator is possible, and an estimator that estimate the position of the object based on a last known position of the object, a last known distance moved by the moving body, or a last known relative speed.

To determine a location of a user, a computing device transmits an audio signal via a speaker and receives a reflected audio signal via a microphone. The computing device obtains sensor data from at least one of: one or more positioning sensors, one or more accelerometers, one or more gyroscopes, or one or more inertial measurement units, and determines a location of a user based on (i) a round trip time of the audio signal and the reflected audio signal, and (ii) the sensor data.

The disclosure relates to a method and a device for determining relevant variables of an object in the environment of a motor vehicle by means of at least one ultrasonic, the method comprising: acquiring a measurement series of real sensor values for the at least one ultrasonic sensor, which sensor values represent the shortest distance between the object and the motor vehicle, wherein the sensor values are acquired cyclically with a specified time interval, modeling a series of sensor values for the at least one ultrasonic sensor by modeling the object movement using a state vector and a parameter vector, and modeling the distance sensing in accordance with the state vector and the parameter vector, and determining the state vector and the parameter vector by adapting the modeled sensor values to the measured real sensor values of the at least one ultrasonic sensor by means of an optimization method.