An approach to obtain low latency association of the audio clock in a smartphone with an incoming RF message is to use an interrupt driven routine, where the receipt of the RF message preamble generates an interrupt that reads the audio clock counter since the start of the audio session. In some embodiments such an approach may be implemented on the specialized processing cores found in smartphones that control RF communication, sensor or audio processing.

A method for positioning an underwater glider based on a virtual TDOA of a single beacon is provided. In the method, a positioning beacon periodically sends positioning messages, where the positioning message includes longitude, latitude and depth information of the positioning beacon; the underwater glider receives the positioning messages and records TOAs at which the positioning messages arrive at an acoustic positioning signal receiving module; and the underwater glider parses the positioning messages and stores positioning message data, creates virtual beacons based on beacon information and attitude information of the underwater glider, corrects the TOAs, and calculates a position of the underwater glider according to a TDOA algorithm. According to the method, the underwater glider passively listens to and receives the positioning messages without sending a positioning request to the positioning beacon, making the entire positioning process energy-saving with a certain degree of concealment.

A method for positioning an underwater glider based on a virtual TDOA of a single beacon is provided. In the method, a positioning beacon periodically sends positioning messages, where the positioning message includes longitude, latitude and depth information of the positioning beacon; the underwater glider receives the positioning messages and records TOAs at which the positioning messages arrive at an acoustic positioning signal receiving module; and the underwater glider parses the positioning messages and stores positioning message data, creates virtual beacons based on beacon information and attitude information of the underwater glider, corrects the TOAs, and calculates a position of the underwater glider according to a TDOA algorithm. According to the method, the underwater glider passively listens to and receives the positioning messages without sending a positioning request to the positioning beacon, making the entire positioning process energy-saving with a certain degree of concealment.

An exemplary communications system includes a first base station and a second base station. The first base station transmits a first signal to the second base station, and the second base station receives the first signal and transmits a second signal in response. The first base station receives the second signal and transmits a third signal in response. A receiving unit of a device receives the first, second, and third signals. The device measures a first delay time between receipt of the first signal and receipt of the second signal, and measures a first round trip time based on receipt of the second signal and the third signal. A second round trip time and a second delay time are determined and a first time difference of arrival is calculated based on the first round trip time, first delay time, second round trip time and second delay time.

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.

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 lightshow control system for generating a lightshow across a plurality of pixels or mobile devices comprises a controller configured to receive a lightshow operator's input and to generate a plurality of lightshow parameters. The system comprises a beacon transmitter in communication with the lightshow controller and configured to receive the lightshow parameters from the lightshow controller, encode the lightshow parameters on a beacon signal, and broadcast the beacon signal to the pixels, wherein each pixel is configured to receive and decode the beacon signal to perform one or more display actions. The decoded beacon signal includes reference timing information to facilitate synchronization of the pixels. The display actions may be based in part on the individual pixel location which is determined by the pixel based on TDOA multilateration and/or trilateration from distinct audio signals emitted by a plurality of speaker nodes.

A lightshow control system for generating a lightshow across a plurality of pixels or mobile devices comprises a controller configured to receive a lightshow operator's input and to generate a plurality of lightshow parameters. The system comprises a beacon transmitter in communication with the lightshow controller and configured to receive the lightshow parameters from the lightshow controller, encode the lightshow parameters on a beacon signal, and broadcast the beacon signal to the pixels, wherein each pixel is configured to receive and decode the beacon signal to perform one or more display actions. The decoded beacon signal includes reference timing information to facilitate synchronization of the pixels. The display actions may be based in part on the individual pixel location which is determined by the pixel based on TDOA multilateration and/or trilateration from distinct audio signals emitted by a plurality of speaker nodes.