A system includes first and second handheld devices. The first device transmits an acoustic signal, and the acoustic signal is reflected from an input object. The second device receives a received signal derived from a reflection of the acoustic signal from the input object. The second device determines information about the location or motion of the input object based on the received signal, and thereby detects a gesture performed by the input object.

A method for determining a change in a distance, a location prompting method and an apparatus and a system thereof are provided. The method includes: sending, by a receiving terminal, a paring request to a server for the server to forward the paring request to a transmitting terminal, and to allocate a frequency band for the receiving terminal and the transmitting terminal after the transmitting terminal accepts the paring request; acquiring, by the receiving terminal, an acoustic wave signal of a frequency sent by the transmitting terminal, wherein the frequency is determined by the transmitting terminal based on the allocated frequency band; determining, by the receiving terminal, a change in the acquired acoustic wave signal; and determining, by the receiving terminal, a change in a distance between the transmitting terminal and the receiving terminal according to the change in the acquired acoustic wave signal.

A method for determining a change in a distance, a location prompting method and an apparatus and a system thereof are provided. The method includes: sending, by a receiving terminal, a paring request to a server for the server to forward the paring request to a transmitting terminal, and to allocate a frequency band for the receiving terminal and the transmitting terminal after the transmitting terminal accepts the paring request; acquiring, by the receiving terminal, an acoustic wave signal of a frequency sent by the transmitting terminal, wherein the frequency is determined by the transmitting terminal based on the allocated frequency band; determining, by the receiving terminal, a change in the acquired acoustic wave signal; and determining, by the receiving terminal, a change in a distance between the transmitting terminal and the receiving terminal according to the change in the acquired acoustic wave signal.

A method for determining position of an aircraft with reference to a location on the ground includes transmitting an acoustic signal from a position on the aircraft to an array of spaced apart acoustic sensors proximate the location. The method includes at least one of (i) determining a time difference of arrival of the acoustic signal between each of the acoustic sensors and a reference acoustic sensor and (ii) determining an arrival time of the acoustic signal at each of the spaced apart acoustic sensors. The position of the aircraft is determined from the time differences of arrival and/or the arrival times.

A tracking method is disclosed. The method may include displaying visual content on a screen. A base station may be stationary with respect to the screen while the visual content is being displayed. In contrast, one or more objects may move with respect to the screen while the visual content is being displayed. The one or more objects may be tracked so that the movement thereof may be used to alter the visual content. Such tracking may involve the base station and the one or more objects sending and/or receiving one or more ultrasonic pulses. The tracked object also determines information using an inertial sensor assembly that receives a synchronization signal coordinated with the one or more ultrasonic pulses. Time-difference-of-arrival and/or time-of-flight of the one or more ultrasonic pulses may then be used to estimate a relative location and/or a relative orientation of the one or more objects with respect to the base station in three dimensional space, so that the estimate is fused with information determined by the inertial sensor assembly using the synchronization signal.

A tracking method is disclosed. The method may include displaying visual content on a screen. A base station may be stationary with respect to the screen while the visual content is being displayed. In contrast, one or more objects may move with respect to the screen while the visual content is being displayed. The one or more objects may be tracked so that the movement thereof may be used to alter the visual content. Such tracking may involve the base station and the one or more objects sending and/or receiving one or more ultrasonic pulses. The tracked object also determines information using an inertial sensor assembly that receives a synchronization signal coordinated with the one or more ultrasonic pulses. Time-difference-of-arrival and/or time-of-flight of the one or more ultrasonic pulses may then be used to estimate a relative location and/or a relative orientation of the one or more objects with respect to the base station in three dimensional space, so that the estimate is fused with information determined by the inertial sensor assembly using the synchronization signal.

The invention discloses a recovery assistance device for helping in rescuing victims of avalanches, earthquakes or boat capsizes. The device is capable of calculating a position from combinations of a previous position and distances to other devices. Different configurations are possible, with a basic configuration consisting of a smart phone having waveform generation capabilities, processing and GNSS receiving capabilities. The device is programmed to be used in a defined mission by an application. The device can also receive a number of add-ons as a battery add-on, a modem add-on, a sound wave generation add-on, antennas, and protection, possibly waterproof, if adequate. Devices of the same type can be carried by people to be rescued and rescuers. The device is therefore quite versatile and can increase significantly the efficiency of rescue teams in different use case scenarios.

The invention discloses a recovery assistance device for helping in rescuing victims of avalanches, earthquakes or boat capsizes. The device is capable of calculating a position from combinations of a previous position and distances to other devices. Different configurations are possible, with a basic configuration consisting of a smart phone having waveform generation capabilities, processing and GNSS receiving capabilities. The device is programmed to be used in a defined mission by an application. The device can also receive a number of add-ons as a battery add-on, a modem add-on, a sound wave generation add-on, antennas, and protection, possibly waterproof, if adequate. Devices of the same type can be carried by people to be rescued and rescuers. The device is therefore quite versatile and can increase significantly the efficiency of rescue teams in different use case scenarios.

A method and system for locating a sound source are provide. The method may include detecting a sound signal of a sound by each of two audio sensors. The method may also include converting the sound signals detected by the two audio sensors from a time domain to a frequency domain. The method may further include determining a high frequency ratio of each of the sound signals in the frequency domain. The method may further include determining a direction of the sound source based on the high frequency ratios.

Tracking systems have been successfully applied to immersive simulation systems and virtual environment training in which portable devices (i.e., hand-held military equipment) within the immersive simulation system are tracked using time-of-fright recordings to triangulate each devices position. Until now, tracking systems have not used differential calculations to track these portable devices. The invention uses a single array of sensors mounted above the simulation area to communicate with small transmitters and emitters mounted on each portable device to generate position offsets for each portable device.