Methods and apparatus to detect proximity of objects to computing devices using near ultrasonic sound waves are disclosed. An example apparatus includes a signal generator to cause a speaker of a computing device to produce a series of pulses. Successive ones of the pulses are spaced at fixed intervals. Ones of the pulses having a central frequency between 18 kHz and 24 kHz. The example apparatus includes an echo profile generator to process noise information sensed by a microphone of the computing device. The noise information includes the pulses and echoes of the pulses reflected off objects in a vicinity of the computing device. The example apparatus further includes an object detection analyzer to determine whether a first object is within an activation region associated with the computing device based on the pulses and the echoes sensed by the microphone.

A system and method is disclosed for calibrating the volume of storage containers using ultrasonic inspection techniques. The exemplary ultrasonic calibration system comprises a plurality of acoustic devices controllably deployed in respective positions on the outside surface of the container. The acoustic devices include a transducer for sending acoustic signals across the internal volume of the container and sensors configured to detect the acoustic signals. The acoustic devices are in communication with a diagnostic computing device that controls the positioning and the operation of the acoustic devices and is further configured to determine the time time-of-flight of acoustic signals that travel between the various acoustic devices. Moreover, according to the specific arrangement of acoustic devices and the measured acoustic signal information, the control computer is configured to calculate the dimensions of the container and its internal volume.

An acoustic sensor system for an aircraft includes a transmitter configured to emit acoustic signals external to the aircraft, and at least one microphone positioned on an exterior of the aircraft and configured to sense the acoustic signals as sensed data. The acoustic sensor system is configured to direct the acoustic signals to the at least one microphone such that a sound pressure level is attenuated perpendicular to the aircraft.

An acoustic sensor system for an aircraft, and method for operating the same, includes a transmitter, at least one microphone, and a control circuit. The transmitter is configured to emit acoustic signals external to the aircraft. The at least one microphone is positioned on an exterior of the aircraft and configured to sense the acoustic signals as sensed data. The control circuit is configured to receive the sensed data and control the transmitter through a drive circuit, and is configured to detect an environmental condition and control the transmitter to emit the acoustic signals at a reduced intensity based on the detected environmental condition.

A transducer system with transducer and circuitry for applying a pulse train at a single frequency to excite the transducer. The transducer is operable to receive an echo waveform in response to the pulse train. The system also comprises circuitry for determining a time of flight as between a first reference time associated with the pulse train and a second reference time associated with the echo waveform.

An air data sensor can include an acoustic transmitter configured to output an acoustic signal into an airflow and a plurality of acoustic transducers configured to receive the acoustic signal output by the acoustic transducer. The air data sensor can also include a light source configured to output a light beam into the airflow, and a light receiver configured to receive scattered light from the light beam. The light source and the light receiver can be bistatic such that a measurement zone is formed away from the air data sensor.

Broadband signal transmissions may be used for object detection and/or ranging. Broadband transmissions may comprise a pseudo-random bit sequence or a bit sequence produced using, a random process. The sequence may be used to modulate transmissions of a given wave type. Various types of waves may be utilized, pressure, light, and radio waves. Waves reflected by objects within the sensing volume may be sampled. The received signal may be convolved with a time-reversed copy of the transmitted random sequence to produce a correlogram. The correlogram may be analyzed to determine range to objects. The analysis may comprise determination of one or more peaks/troughs in the correlogram. Range to an object may be determines based on a time lag of a respective peak.

A device comprises a processor communicatively coupled with an ultrasonic sensor which is configured to repeatedly emit ultrasonic pulses during transmit periods which are interspersed with receive periods. Returned ultrasonic signals corresponding to the emitted ultrasonic pulses are received by the ultrasonic sensor during the receive periods. The processor is configured to direct the ultrasonic sensor to listen, during a listening window, for a potentially interfering ultrasonic signal from a second ultrasonic sensor. The listening window is prior to a transmit period of the transmit periods. In response to detecting the potentially interfering ultrasonic signal during the listening window, the processor is configured to adjust operation of the ultrasonic sensor to avoid an ultrasonic collision with the second ultrasonic sensor to facilitate coexistence of the ultrasonic sensor and the second ultrasonic sensor in an operating environment shared by the ultrasonic sensor and the second ultrasonic sensor.

A system for tracking wearable user devices is provided herein. The system may include a tracking environment, comprising: one or more scene light sources, wherein the location of the scene light sources is known within said tracking environment; one or more scene detectors operable to detect light within the tracking environment, wherein the location and orientation of said one or more scene detectors is known within said tracking environment; one or more scene reflectors operable to reflect light originating from said one or more scene light sources, wherein the location of said one or more scene reflectors is known within said tracking environment; and, one or more wearable user devices comprising a curved reflective surface with known geometry; and, a computer processor operable to analyse light readings detected by said one or more scene detectors, and to calculate a position of the one or more wearable user devices.

The invention relates to a device for locating a target, comprising: a generator of ultrasonic waves that can be reflected by the target; pairs of first and second sensors repeated in a first direction, the first and second sensors of each pair being arranged in a second direction different from the first direction; and a processing unit suitable for: a) for each pair of sensors, measuring the phase shift between the ultrasonic waves received by the first sensor and by the second sensor; and b) establishing that the target is found on a surface corresponding to the differences between measured phase shifts.