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 goggles.

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.

A system for determining the location of a mobile receiver unit includes static transmitter units, each including a respective clock which it uses to transmit a positioning signal according to a respective transmission schedule. The mobile receiver unit receives a positioning signal from any of the static transmitter units. A first processing means uses information relating to the received positioning signal to determine the location of the mobile receiver unit. A second processing means uses information relating to a respective drift and/or offset of each of the clocks of the static transmitter units to generate transmission schedules for the static transmitter units. Each transmission schedule instructs a respective static transmitter unit to transmit a positioning signal at one or more scheduled times according to the clock of the static transmitter unit.

A system for determining the location of a mobile receiver unit includes static transmitter units, each including a respective clock which it uses to transmit a positioning signal according to a respective transmission schedule. The mobile receiver unit receives a positioning signal from any of the static transmitter units. A first processing means uses information relating to the received positioning signal to determine the location of the mobile receiver unit. A second processing means uses information relating to a respective drift and/or offset of each of the clocks of the static transmitter units to generate transmission schedules for the static transmitter units. Each transmission schedule instructs a respective static transmitter unit to transmit a positioning signal at one or more scheduled times according to the clock of the static transmitter unit.

An approach for providing a lower cost real time location system in less trafficked areas of a building. This approach uses on-board audio capabilities of a mobile device to receive a room response trace resulting from a self-generated acoustic signal. By comparing the room response trace to a modeled room response trace, the location of the mobile device is determined.

An approach for providing a lower cost real time location system in less trafficked areas of a building. This approach uses on-board audio capabilities of a mobile device to receive a room response trace resulting from a self-generated acoustic signal. By comparing the room response trace to a modeled room response trace, the location of the mobile device is determined.

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.

The disclosed threat response system(s) and method(s) provide a mean to secure an area around the clock. The system includes a plurality of microphones strategically located at various locations of the protected area, a plurality of acoustic beacons to provide navigational support one or more autonomous non-flying (ANF) drones, and a central controller. In one example each of the one or more ANF drones are equipped with an acoustic positioning system that uses beacon signals (e.g., mechanical waves) transmitted by the plurality of acoustic beacons to determine its position relative to the plurality of acoustic beacons. Once an acoustic event is detected, it is analyzed to determine whether there is a threat. When the threat is confirmed, the central controller dispatches one or more of the ANF drones to investigate and/or to engage the target.