Systems and techniques are described that provide automated parking assistance for a vehicle. In some implementations, a parking assistance apparatus includes a frequency generator configured to generate a first frequency and a second frequency, and generate at least one synthesized frequency that is synthesized from the first frequency and the second frequency. The apparatus also includes a piezoelectric converter configured to, using piezoelectric effects, transmit ultrasonic waves having the at least one synthesized frequency, and receive reflected ultrasonic waves that result from the transmitted ultrasonic waves being reflected by an object. The apparatus also includes a filter unit configured to detect a predetermined frequency from the reflected ultrasonic waves.

A survey system including a multibeam echo sounder having a single projector array and a single hydrophone array constructs a multi-component message for ensonifying multiple fans and deconstructs a corresponding message echo for use in analyzing the returns from each fan.

A system may include a sensor system and a control system configured for communication with the sensor system. The sensor system may include an ultrasonic sensor system. The control system may be capable of determining, based at least in part on signals from the ultrasonic sensor system, whether a personal medical device is within a predetermined distance from the mobile device. The control system may be capable of adjusting one or more mobile device settings in response to a determination that the personal medical device is within the predetermined distance of the mobile device.

A system may include a sensor system and a control system configured for communication with the sensor system. The sensor system may include an ultrasonic sensor system. The control system may be capable of determining, based at least in part on signals from the ultrasonic sensor system, whether a personal medical device is within a predetermined distance from the mobile device. The control system may be capable of adjusting one or more mobile device settings in response to a determination that the personal medical device is within the predetermined distance of the mobile device.

An air-coupled ultrasonic interferometric method is disclosed. An air-coupled ultrasonic transducer, as a probe, is placed directly facing the surface of a workpiece, and an ultrasonic wave is reflected back and forth between the ultrasonic transducer and the surface of the workpiece; the phase difference of the first echo reflected from the surface of the workpiece and reaching the air-coupled ultrasonic transducer is measured; based on the change of the ultrasonic frequency and wavelength, the measured distance is transformed into the rate of change of the acoustic phase with respect to the acoustic angular frequency, wherein the change in the acoustic angular frequency is a product obtained by multiplying 2π by the difference between the highest frequency F2 and the lowest frequency F1 within the bandwidth fB of the air-coupled ultrasonic transducer.

An acoustic antenna intended to equip a sonar, the antenna being centred around a first longitudinal axis and includes at least a first assembly of at least two transducers and a second assembly of at least two transducers stacked along the longitudinal axis, each transducer having at least a radial mode having a resonance frequency, referred to as the radial frequency, and a cavity mode having a resonance frequency, referred to as the cavity frequency, wherein the transducers of the first assembly are configured to transmit sound waves in a first continuous frequency band extending at least between the cavity and radial frequencies of the transducers of the first assembly and the transducers of the second assembly are configured to transmit sound waves in a second continuous frequency band extending at least between the cavity and radial frequencies of the transducers of the second assembly, in that the cavity frequency of a transducer of the second assembly is equal to the radial frequency of a transducer of the first assembly plus or minus (fr1−fc1)/10, fr1 being the radial frequency of the transducer of the first assembly and fc1 being the cavity frequency of the transducers of the first assembly and wherein the transducers of the second assembly are positioned between the transducers of the first assembly and in that no transducer of the first assembly is positioned between the transducers of the second assembly.

An acoustic antenna intended to equip a sonar, the antenna being centred around a first longitudinal axis and includes at least a first assembly of at least two transducers and a second assembly of at least two transducers stacked along the longitudinal axis, each transducer having at least a radial mode having a resonance frequency, referred to as the radial frequency, and a cavity mode having a resonance frequency, referred to as the cavity frequency, wherein the transducers of the first assembly are configured to transmit sound waves in a first continuous frequency band extending at least between the cavity and radial frequencies of the transducers of the first assembly and the transducers of the second assembly are configured to transmit sound waves in a second continuous frequency band extending at least between the cavity and radial frequencies of the transducers of the second assembly, in that the cavity frequency of a transducer of the second assembly is equal to the radial frequency of a transducer of the first assembly plus or minus (fr1−fc1)/10, fr1 being the radial frequency of the transducer of the first assembly and fc1 being the cavity frequency of the transducers of the first assembly and wherein the transducers of the second assembly are positioned between the transducers of the first assembly and in that no transducer of the first assembly is positioned between the transducers of the second assembly.

Ranging systems operate based on the transmission and receipt of pseudorandom sequences. Pseudorandom sequences may be generated and assigned to specific transmitters, which may operate simultaneously to transmit signals including the pseudorandom sequences. A receiver may be programmed to recognize the specific pseudorandom sequences within data captured by the receiver, and to associate the pseudorandom sequences with the transmitters that transmitted them. Upon identifying the pseudorandom sequences, the receiver or one or more associated components may calculate times of flight of signals transmitted by the respective transmitters. Such times of flight may be used to calculate distances to one or more objects from which the signals were reflected.

Ranging systems operate based on the transmission and receipt of pseudorandom sequences. Pseudorandom sequences may be generated and assigned to specific transmitters, which may operate simultaneously to transmit signals including the pseudorandom sequences. A receiver may be programmed to recognize the specific pseudorandom sequences within data captured by the receiver, and to associate the pseudorandom sequences with the transmitters that transmitted them. Upon identifying the pseudorandom sequences, the receiver or one or more associated components may calculate times of flight of signals transmitted by the respective transmitters. Such times of flight may be used to calculate distances to one or more objects from which the signals were reflected.

A survey system including a multibeam echo sounder and a beam selector for selecting beams with the largest amplitudes.