An electronic device may include an infrared light source and an infrared image sensor to enable infrared beacon functionality. In a location sharing scenario, a first electronic device may use the infrared light source to emit infrared light and serve as an infrared beacon. A second electronic device may use the infrared image sensor to detect the infrared beacon and identify the location of the first electronic device. The infrared image sensor that is used to detect the infrared beacon may also serve as a time-of-flight sensor for a light detection and ranging (LiDAR) module. The second electronic device (that detects the infrared beacon) may provide output such as visual, audio, and/or haptic output to inform a user of the location of the infrared beacon.

A trackable camera beacon is provided that is mountable onto a camera, so that the camera can be more easily tracked and automatically controlled. The camera beacon obtains lens data from the lens of a camera, position data corresponding to the camera beacon, and outputs a unified and synchronized data packet. The unified and synchronized output includes position, orientation and lens data. This can be used to also control the camera, such as the focus, iris and zoom parameters of the lens.

A system is configured to obtain locations of a mobile device (1) and obtain presence detection information. The locations are determined using visible light signals and dead reckoning information recorded at different moments. The presence detection information indicates presence detected using presence sensor devices (31, 32) at the different moments. The system is further configured to obtain sensor locations and sensor fields of view, determine sensor orientations based on the locations of the mobile device, the sensor locations and the presence detection information, and determine a sensor coverage area (61, 62), comprising gaps in the sensor coverage area, based on the sensor locations, the sensor orientations and the sensor fields of view. The system is also configured to determine one or more parameters for presence detection based on the gaps in the sensor coverage area and output the parameters or a presence detection result which has been determined using the parameters.

A system for three-dimensional animal tracking in laboratory conditions is proposed. A mobile device that has one infrared and one ultrasonic sensor, equipped with memory and/or radio transmitter, is attached to a moving creature. One compact stationary box is placed in the vicinity; it emits a pre-determined sequence of short infrared pulses, short ultrasonic signals and two planar, radially emitted light beams that move through the area of interest with constant angular speed in two orthogonal directions. The mobile device receives two angular coordinates in the form of two time intervals between an infrared pulse and the next two orthogonal planar beam receptions, and it receives one linear coordinate in the form of the time interval between an infrared pulse and the next ultrasonic signal reception, taking into account the speed of sound in the air. The ultrasonic emitter is driven by a pulse-width modulated signal to make it undetectable by animals.

A trackable camera beacon is provided that is mountable onto a camera, so that the camera can be more easily tracked and automatically controlled. The camera beacon obtains lens data from the lens of a camera, position data corresponding to the camera beacon, and outputs a unified and synchronized data packet. The unified and synchronized output includes position, orientation and lens data. This can be used to also control the camera, such as the focus, iris and zoom parameters of the lens.

Circuits for controlling magnetic-based tracking systems are described. These systems may be used in virtual reality applications, for example to track in real-time the location of one or more body parts. The systems use a beacon emitting mutually orthogonal magnetic fields. On the receiver side, one or more sensors disposed on different parts of a body receive the magnetic fields. The beacon includes switching amplifiers for driving the magnetic field emitters. Being binary, these amplifiers may be controlled by binary signals. The circuits may exhibit a resonant frequency response, and may be operated off-resonance, thus providing for a better control of the magnetic fields amplitude. As a result, however, fluctuations in the envelop of the magnetic fields due to the presence of a beating tone may arise. These fluctuations may be shortened by gradually activating the drivers for the magnetic field emitters.

A localization system 100 comprising multiple beacons 120 and an assignment system 110 is provided. The assignment system is arranged to assign a temporary location identifier to a location identifier associated with a beacon. A scheduler 150 is arranged to schedule the assigning of temporary location identifiers according to a schedule. It is avoided that the beacons have a fixed location identifier, thus third parties cannot create a mapping between the temporary location identifiers and the locations of the beacons.

A tracking beacon is provided that is trackable using image sensors. The beacon includes a housing with a lower portion and an upper portion. The upper portion include a light diffusing structure with protrusions to help scatter the emitted light in different directions. A light source is positioned within the housing, and electrical contacts are positioned on an external surface of the lower portion.

An underwater communications network may include spaced apart nodes on a bottom of a body of water. The underwater communications network may also include fiber optic cabling connecting the spaced apart nodes. Each node may include a frame, a node short-range navigation device carried by the frame, and an unmanned underwater vehicle (UUV) carried by the frame after delivering a fiber optic cable along a navigation path from an adjacent node. The UUV may be configured to cooperate with the node short-range navigation device during an end portion of the navigation path adjacent the frame.

Circuits for controlling magnetic-based tracking systems are described. These systems may be used in virtual reality applications, for example to track in real-time the location of one or more body parts. The systems use a beacon emitting mutually orthogonal magnetic fields. On the receiver side, one or more sensors disposed on different parts of a body receive the magnetic fields. The beacon includes switching amplifiers for driving the magnetic field emitters. Being binary, these amplifiers may be controlled by binary signals. The circuits may exhibit a resonant frequency response, and may be operated off-resonance, thus providing for a better control of the magnetic fields amplitude. As a result, however, fluctuations in the envelop of the magnetic fields due to the presence of a beating tone may arise. These fluctuations may be shortened by gradually activating the drivers for the magnetic field emitters.