A system and methods for estimating the location of a mobile device are disclosed. In accordance with one embodiment, a mobile device receives, at a first time t.sub.1, a wireless electromagnetic signal, where the wireless electromagnetic signal comprises a first identifier that identifies a first beacon that transmitted the wireless electromagnetic signal. The mobile device receives, at a second time t.sub.2, t.sub.2>t.sub.1, an ultrasound signal lacking an identification of the source of the ultrasound signal. A time difference of arrival (TODA) t.sub.2−t.sub.1 is compared to a maximum TDOA. A location of the mobile device is estimated based on the TDOA only when the TDOA is less than or equal to the maximum TDOA.

Systems and methods for facilitating acoustic-based localization and motion tracking in the presence of multipath, wherein, in operation, acoustic signals are transmitted from a speaker to a microphone array, a processor coupled to the microphone array calculates the 1 D distance between a microphone and/or each microphones of the microphone array and the speaker of a user device by first filtering out multipath signals with large time-of-arrival values relative to the time-of-arrival value of the direct path signal, then extracting out the phase value of the residual multipath signals and direct path signal, using the calculated 1 D distances, the processor may then calculate the intersection of the 1 D distances to determine the 3D location of the speaker to enable sub-millimeter accuracy of 1 D distance between a microphone of a microphone array and a speaker of a user device to enable smaller separation between the microphones of the microphone array.

A system and methods for estimating the location of a mobile device are disclosed. In accordance with one embodiment, a mobile device located within a first corridor of a building receives (1) a first wireless electromagnetic signal and a first ultrasound signal from a first beacon located in the first corridor, (2) a second wireless electromagnetic signal and a second ultrasound signal from a second beacon located in the first corridor, and (3) a third wireless electromagnetic signal from a third beacon located in a second corridor of the building. The first wireless electromagnetic signal, the first ultrasound signal, the second wireless electromagnetic signal, and the second ultrasound signal are used to estimate a location of the mobile device.

A system and methods for estimating the location of a mobile device are disclosed. In accordance with one embodiment, a mobile device receives an ultrasound signal lacking an identification of the source of the ultrasound signal. One or both of the mobile device or a server identify which of a plurality of beacons transmitted the ultrasound signal based on the time at which the mobile device received the ultrasound signal and the time at which the mobile device received a wireless electromagnetic signal prior to receiving the ultrasound signal. One or both of the mobile device or the server estimate a location of the mobile device based on the identified beacon and on the times at which the mobile device received the wireless electromagnetic and ultrasound signals.

This document describes a system and method for determining a location of a mobile device within an enclosed space using audio localization techniques. In particular, the system and method utilizes audio localization techniques to identify the location of a mobile device within a multi-storey multi-room structure or an enclosure with multiple rooms.

An underwater celestial navigation beacon configured to provide position information is disclosed. The underwater celestial navigation beacon can include a data store configured to store an astronomical model of the moon. The underwater celestial navigation beacon can include an inertial measurement unit (IMU) operable to capture IMU data that includes three-axis acceleration data and three-axis rate gyroscopic data. The underwater celestial navigation beacon can include a controller. The controller can determine a latitude of the underwater celestial navigation beacon using the three-axis rate gyroscopic data. The controller can determine a longitude of the underwater celestial navigation beacon based on a gravitational pull of the moon, using the three-axis acceleration data and the astronomical model of the moon. The controller can determine the position information for the underwater celestial navigation beacon based on the latitude and longitude.

Examples of the disclosure relate to apparatus (101) for positioning mobile devices (105). The apparatus (101) comprises means for: obtaining a time of arrival of at least one audio signal (131) at a mobile device (105), wherein the audio signal (131) is generated with a photoacoustic effect; and using the time of the arrival of the audio signal (131) to estimate a location of the mobile device (105).

Deployable navigation beacons can be deployed from a vehicle, such as an unmanned aerial vehicle (UAV), in an event of a loss of position or orientation of the vehicle. After deployment of the navigation beacons, the vehicle may detect locations of the navigation beacon, which may define a surface that may include surface features. The vehicle may then perform control operations based on the resolved locations. For example, UAV may maneuver to land proximate to the navigation beacons after resolving locations of the navigation beacons as a continuous surface. The navigation beacons may output a visual signal (e.g., a light), a auditory signal (e.g., a sound), and/or a radio signal. In some embodiments, each navigation beacon may include a different or unique signal.

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.

A sensor positioning device includes an inter-sensor distance measurement jig that measures a distance between two sensors, and is a reference when setting the distance between the two sensors to a target distance, and reference-setting jigs of sensor height position, each including a weight and a weight suspension member, a lengthwise direction of which is in a vertical direction when the weight is suspended, and each performing setting of a distance which is a total of a vertical direction dimension of the weight, a length of the weight suspension member, and a distance from an upper end of the weight suspension member to the sensor such that the distance coincides with a target height of the sensor, when the weight is in contact with a reference surface, in a state where the weight is attached to a sensor holding jig by the weight suspension member.