An ultrasonic transmitter apparatus is configured to transmit an ultrasonic signal that communicates a binary identifier. The apparatus includes an ultrasound transmission system and is configured to transmit an ultrasonic signal that communicates the binary identifier according to an encoding in which each bit position in the binary identifier is associated with a respective pair of frequencies and with respective first and second time positions in the ultrasonic signal. The value of the bit position in the binary identifier determines which frequency of the pair of frequencies is transmitted at the first respective time position in the ultrasonic signal, with the other frequency of the pair of frequencies being transmitted at the second respective time position in the ultrasonic signal.

A distance detection device and a distance detection method thereof are provided. A second time at which a packet amplitude peak of a preset sound signal is received by a sound receiver is estimated according to a time difference between the preset sound signal and a low pass filter signal thereof. A distance between a speaker and the sound receiver is calculated according to the second time.

An information provision apparatus includes: an information signal generator unit that generates an information signal containing information on a provision target; a converter unit that converts the generated information signal into a sound wave and outputs the sound wave; and a wireless communicator unit that performs wireless transmission and reception of data with a communication apparatus. Further, the information provision apparatus is enabled to receive an activation signal transmitted using a specific wireless transmission medium from a signal output apparatus. In response to that the activation signal is received, the information provision apparatus transitions into a state enabling wireless transmission and reception of data with the communication apparatus.

The present disclosure relates to a location determination system that includes acoustic transmitting devices, location tags, and a wireless mesh network, where the wireless mesh network uses battery-powered devices. A location tag receives acoustic signals (e.g., ultrasound signals) from an acoustic transmitting device. Clocks from members of the wireless mesh network are synchronized by observation of clock pairings, each clock pair formed by respective clocks in a transmitting device that transmits a message and a receiving device that receives the message. By analyzing the observed clock pairings, a best fit between the clock pairings may be determined. After selecting a reference clock, an acoustic transmission schedule may be propagated to the respective acoustic transmitting device.

The ultrasonic homing assembly includes a base unit that may be coupled to a boat anchor. A base processor is coupled to the base unit. A transmitter is coupled to the base unit. The transmitter is operationally coupled to the processor. The transmitter transmits a location signal. A remote unit may be worn by a diver. A remote processor is coupled to the remote unit. A receiver is coupled to the remote unit. The receiver is operationally coupled to the remote processor. The receiver receives the location signal from the transmitter. A display is coupled to the remote unit. The display is operationally coupled to the processor. The display directs the diver toward the base unit. The diver swims toward the boat anchor.

A method and apparatus for locating a target in a venue is described. A backend controller activates transmitters in a venue to send burst signals using a double symmetry configuration formed of a plurality of separate transmitter groups. The backend controller activates the transmitters into a second, different configuration for bursting. The resulting location signal information from each configuration is obtained by the backend controller, which then more accurately determines the location of the target in the venue.

An ultrasonic sensor has: a diaphragm that includes at least two partial regions for emitting and/or receiving ultrasonic signals, the two partial regions possessing different resonance characteristics; and at least one electromechanical transducer coupled to the diaphragm, to which transducer a control signal having at least two different control signal frequencies is applied. In this context, a first control signal frequency is in the range of a resonant frequency of a first partial region of the diaphragm, and a second control signal frequency is in the range of a resonant frequency of a second partial region of the diaphragm. Alternatively, two electromechanical transducers are used, which are coupled to a diaphragm and have different resonance characteristics.

A system and method is described for generating a confidence level for data generated by a beamforming acoustic beacon system. The system may include an audio emission device to emit a set of sounds corresponding to a set of predefined modal patterns into a listening area. The sounds may be detected by an audio capture device to produce a set of impulse responses corresponding to the modal patterns. The impulse responses may be processed to produce a set of window synthesized impulse responses for various angles. These window synthesized impulse responses may (1) be formed based on a weighted set of the modal patterns that were originally used to emanate sound and (2) seek to emulate a target beam, which is also composed of the same weighted modal patterns. A confidence level may be computed based on the difference between the window synthesized impulse responses and the target beam pattern.

The present technology may be directed a system for determining an angle and distance between a positioning node and secondary device using a plurality of acoustic transmitters to transmit acoustic ranging signals that are modulated using ranging sequences, respectively. The system includes an acoustic receiver to detect the acoustic ranging signals, and a signal processor to calculate times of arrival and a plurality of aliased angles of arrival of the acoustic ranging signals. An anti-aliasing module may select an angle of arrival from the calculated plurality of aliased angles using the times of arrival of the acoustic ranging signals. A time of flight may be calculated from a comparison of times of arrival for radio signals and the acoustic signals. The time of flight may be used to calculate the distance between the positioning node and secondary device.