A tracking method includes displaying visual content on a screen of a head mounted display (HMD). One or more base stations 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. Time-difference-of-arrival (TDoA) and/or time-of-flight (ToF) may be measured for one or more ultrasonic pulses transmitted from the base station, one or more objects, or HMD. Position and orientation of the objects and HMD may be calculated based on the TDoA and ToF. Different frequencies of pulses may be used to locate the HMD and the objects. An electromagnetic synchronization signal from the HMD and/or base station may be used to measure TDoA. Position and orientation measurements may be fused with outputs from IMUS (inertial measurement units) to reduce jitter.

A system is provided for determining the position of a mobile receiver unit in an environment. The system comprises: a transmission apparatus comprising a plurality of ultrasound transmitters configured to transmit a plurality of ultrasonic signals in different respective principal directions, each encoding a different respective direction identifier; a mobile receiver unit comprising an ultrasound receiver configured to receive the plurality of ultrasonic signals along a plurality of signal paths, at least one of which includes a reflection off an environment surface; and a processing system comprising a decoder arranged to decode the respective direction identifiers from the received signals. The processing system is configured to determine a respective time of arrival for each signal, and use location information relating to the transmission apparatus and the environment surface, together with the respective direction identifiers and times of arrival to calculate an estimated position of the mobile receiver unit.

A system is provided for determining the position of a mobile receiver unit in an environment. The system comprises: a transmission apparatus comprising a plurality of ultrasound transmitters configured to transmit a plurality of ultrasonic signals in different respective principal directions, each encoding a different respective direction identifier; a mobile receiver unit comprising an ultrasound receiver configured to receive the plurality of ultrasonic signals along a plurality of signal paths, at least one of which includes a reflection off an environment surface; and a processing system comprising a decoder arranged to decode the respective direction identifiers from the received signals. The processing system is configured to determine a respective time of arrival for each signal, and use location information relating to the transmission apparatus and the environment surface, together with the respective direction identifiers and times of arrival to calculate an estimated position of the mobile receiver unit.

The present group of inventions relates to methods and systems for positioning underwater objects, and more particularly to methods and systems in which satellite signals are received by receivers disposed on sonar buoys, the coordinates of the sonar buoys are determined by means of computation modules on the sonar buoys, location data and identification data are transmitted in the form of sonar signals emitted by transmitters on the sonar buoys, the signals are received with the aid of a receiver disposed on an underwater object, and the coordinates of the underwater object are determined according to the time delay of receipt of the sonar signals from the sonar buoys, the location of which is known. The present solution can be used in simultaneously determining the geographical position of an unlimited number of mobile underwater objects, remotely operated underwater vehicles, divers, marine animals, etc. in motion. According to the invention, signals from the aforementioned sonar buoys are encoded in the form of periodic signals tethered to GPS/GLONASS clocks, all transmitters of the sonar signals are disposed at the same depth, and during decoding of the signals from the sonar buoys, direct signals from the sonar buoys are isolated from reflected signals. The system implements the aforementioned method. The achieved technical result is more accurate positioning of the underwater objects.

A robotic mapping and tracking system including a robot and boundary posts are disclosed. The robot includes an ultrasonic transmitter, a processor and a camera component. The boundary posts are configured to be placed adjacent to a boundary of a working region. Each boundary post of the plurality of boundary posts includes an ultrasonic receiver. Time-of-flights of the ultrasonic waves are measured to identify distances in between the robot and boundary posts. The camera component of the robot captures an image of an environment of the robot. The processor of the robot analyzes the image of the environment and identifies at least a portion of the working region in front of the robot from the image. The processor of the robot determines a moving route based on the identified portion of the working region in front of the robot and the distances in between the robot and the boundary posts.

A robotic mapping and tracking system including a robot and boundary posts are disclosed. The robot includes an ultrasonic transmitter, a processor and a camera component. The boundary posts are configured to be placed adjacent to a boundary of a working region. Each boundary post of the plurality of boundary posts includes an ultrasonic receiver. Time-of-flights of the ultrasonic waves are measured to identify distances in between the robot and boundary posts. The camera component of the robot captures an image of an environment of the robot. The processor of the robot analyzes the image of the environment and identifies at least a portion of the working region in front of the robot from the image. The processor of the robot determines a moving route based on the identified portion of the working region in front of the robot and the distances in between the robot and the boundary posts.

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.

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.

An electronic device unit for detection of emergency calls initiated (emanating) from cell phone or other personal wireless communication handheld units, wherein the electronic device unit for detection of emergency calls is installed and integrated as a component detector of a fire alarm system, intrusion alarm system, surveillance system, access control system, SCADA system or other building and facility monitoring systems. A cell phone and other personal wireless devices that transmit special signals that are received by an electronic device unit for detection of emergency calls. A cell phone and other personal wireless devices that performs two way data communications with an electronic device unit for detection of emergency calls.

A positioning system has an initiator device configured for emitting a high-speed wireless signal, at least one reference device configured for receiving the high-speed wireless signal and emitting a low-speed wireless signal after receiving the high-speed wireless signal, at least one target device each having one or more components for receiving the low-speed wireless signals, and at least one engine configured for determining the position of each of the at-least-one target device by calculating the distance between the target device and each of the at-least-one reference device based on at least the times-of-arrival of the low-speed wireless signals, each time-of-arrival being the time that the corresponding low-speed wireless signal being received by the target device, and determining the position of the target device based on the calculated distances.