An ultrasonic locationing system using a dual phase pulse includes an emitter emitting two consecutive frequency bursts, each having a different phase, within one ultrasonic pulse. A receiver microphone receives the ultrasonic pulse, and a processor runs an amplitude-based detection algorithm on the pulse for a band of frequencies of interest and detects a first burst of the pulse within the proper frequency band and having an amplitude exceeding a threshold. Whereupon, the processor determines a relative phase difference between the first burst and a second burst of the pulse and determines whether the relative phase difference is within a predetermined acceptance window, indicating that the pulse is valid for use in locationing the emitter and associated mobile device.

An embodiment of the present invention provides an AI apparatus comprising: a communication unit configured to communicate with a plurality of external AI apparatuses; and a processor configured to: receive sound signals of the user from the plurality of external AI apparatus, calculate a distance and a variation of the distance from each of the plurality of external AI apparatus to the user based on the obtained sound signals, determine a current path of the user based on the calculated distance and the calculated variation of the distance, and determine a future path of the user based on the current path.

A phase array acoustic device using array of horns and optional faceplates is presented. Said horn phased-array acoustic device can be used as a passive sensor, a sound projector, or both (sonar).

It is shown that by correct selection of the fill-factor and apodization faceplate, grating-lobes and side-lobes cab be greatly reduced.

An optional use of acoustic valves as phase-shifter in the wave domain to improve Signal to Noise Ratio is presented.

An optional aperiodic tiling of the horns' mouth to reduces aliasing is presented.

A technique for non-echo pulsed ranging of a mobile device within an environment includes a plurality of emitters within the environment transmitting signal pulses of a predefined frequency to a mobile device that can receive a signal pulse, convert the signal pulse into a digital waveform, store the digital waveform into a buffer having a predetermined length of time, and analyze the digital waveform to detect a signal pulse at the predefined frequency. If a signal pulse is detected, the mobile device can re-analyze the digital waveform that was stored in the buffer to see if another signal pulse can be detected within the waveform, indicating the existence of a reflected signal. If another signal pulse is detected, the mobile device can select the signal pulse that was received first in time, i.e. the direct signal, for use in ranging of the mobile device.

Example methods and systems described herein relate to determining average arrival time of a radio wave emitted by a lightning discharge and/or determining the lobe and/or polarity of the radio wave. The determination of the average arrival time may take a weighted average of arrival times of peaks of the radio wave. The determination of the lobe and/or polarity may depend on an estimated propagation distance, a propagation path profile, and one or more waveform features.

A phase array acoustic device using array of horns and optional faceplates is presented. Said horn phased-array acoustic device can be used as a passive sensor, a sound projector, or both (sonar). It is shown that by correct selection of the fill-factor and apodization faceplate, grating-lobes and side-lobes cab be greatly reduced. An optional use of acoustic valves as phase-shifter in the wave domain to improve Signal to Noise Ratio is presented. An optional aperiodic tiling of the horns' mouth to reduces aliasing is presented.