Systems and methods of estimating a location of a mobile computing device are provided. For instance, acoustic signals can be received from one or more transmitting devices associated with a real-time locating system. A set of peaks can be selected from the received acoustic signals. A first set of transmitter locations can be assigned to the selected set of peaks. The first set of transmitter locations can be specified by an acoustic model specifying a plurality of transmitter locations within an acoustic environment in which the one or more transmitting devices are located. A first model path trace associated with the first set of transmitter locations can be compared to the received acoustic signals. A location of the mobile computing device can be estimated based at least in part on the comparison.

A range-finding and/or object-positioning system comprises one or more target devices; one or more reference devices communicating with said one or more target devices via one or more wireless signal sets, each wireless signal set comprising at least a first-speed signal having a first transmission speed and a second-speed signal having a second transmission speed, and the first transmission speed being higher than the second transmission speed; and at least one processing unit performing actions for determining at least one distance between one target device and one reference device based on the time difference between the receiving time of the first-speed signal and the receiving time of the second-speed signal of the wireless signal set communicated between said reference and target devices.

A range-finding and/or object-positioning system comprises one or more target devices; one or more reference devices communicating with said one or more target devices via one or more wireless signal sets, each wireless signal set comprising at least a first-speed signal having a first transmission speed and a second-speed signal having a second transmission speed, and the first transmission speed being higher than the second transmission speed; and at least one processing unit performing actions for determining at least one distance between one target device and one reference device based on the time difference between the receiving time of the first-speed signal and the receiving time of the second-speed signal of the wireless signal set communicated between said reference and target devices.

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. 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.

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. 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.

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.

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.

A following method and device for an unmanned aerial vehicle and a wearable device are provided. The following method comprises: installing a plurality of receiving sensors on the unmanned aerial vehicle, wherein the plurality of receiving sensors match with one transmitting sensor in a smart control device at the user side; receiving a distance signal transmitted by the user in real time by using the receiving sensors, and calculating a relative position of the unmanned aerial vehicle with respect to the user according to the distance signal; and adjusting the horizontal position of the unmanned aerial vehicle according to the relative position, so that the relative position of the unmanned aerial vehicle with respect to the user agrees with a preset position, to realize automatic following of the unmanned aerial vehicle.

A following method and device for an unmanned aerial vehicle and a wearable device are provided. The following method comprises: installing a plurality of receiving sensors on the unmanned aerial vehicle, wherein the plurality of receiving sensors match with one transmitting sensor in a smart control device at the user side; receiving a distance signal transmitted by the user in real time by using the receiving sensors, and calculating a relative position of the unmanned aerial vehicle with respect to the user according to the distance signal; and adjusting the horizontal position of the unmanned aerial vehicle according to the relative position, so that the relative position of the unmanned aerial vehicle with respect to the user agrees with a preset position, to realize automatic following of the unmanned aerial vehicle.

An apparatus and method for measuring a swimmer's speed and conveying the speed to the swimmer in real time includes a plurality of ultrasonic beacons each having a transducer configured to emit ultrasonic signals in a pool or other body of water within which the swimmer is swimming. A wearable, waterproof, ultrasonic receiver worn by the swimmer, receives the ultrasonic signals and generates corresponding signal data. The receiver's microcontroller captures and uses the signal data to calculate the swimmer's position and speed in real time, and conveys this information to a wearable, waterproof, user interface device worn by the swimmer, the user interface device including a near-eye display disposed on the swimmer's googles.