Abstract: A communication device including a clock, a memory, and at least one processor is disclosed. The at least one processor is configured to execute instructions stored in the memory that cause the at least one processor to perform operations including receiving at least one message from a second communication device of a plurality of communication devices over a preconfigured time duration, determining a first local time of the clock of the communication device at which the at least one message from the second communication device is received, and determining a sync-time of the second communication device based on the at least one message from the second communication device. The operations include mapping the sync-time of the second communication device based on the first local time and the determined sync-time of the second communication device and adjusting a sync-time of the communication device based on the second local time.

Abstract: Systems and methods of determining a location of a mobile computing device associated with a real-time locating system are provided. For instance, a mobile computing device can determine a first location of the mobile computing device. The mobile computing device can then receive acoustic-contextual data that is correlated with the first location of the mobile computing device. The acoustic-contextual data can include data associated with one or more transmitting devices, and data associated with an environment proximate the one or more transmitting devices. The mobile computing device can receive one or more signals from at least one of the one or more transmitting devices, and can determine a more accurate second location of the mobile computing device based at least in part on the acoustic-contextual data and the one or more received signals.

Abstract: An approach for the reliable detection of smartphones within vehicles. The cloud instructs two smartphones, which both detect an in-vehicle detection system, to report signals that reflect major sensor events, together with the timing using their respective clocks. By sending local clock timing and time-sensitive beacon content information to the cloud, the offset between the two smartphone clocks may be determined, thereby enhancing the reliability of the in-vehicle detection of the smartphones.

Abstract: 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.

Abstract: A method for finding door location in an automated way based on observations of people that are equipped with a device whose position is determined acoustically. By observing positioning transitions across internal structures such as walls, the location of doors can be automatically identified.

Abstract: A positioning system comprising a processing system (7; 9) configured to receive a first position estimate for a mobile device (7), and to receive data representative of an acoustic signal received by the mobile device (7) from one of a plurality of acoustic transmitter units (2, 3, 4, 5). For each of the acoustic transmitter units (2, 3, 4, 5), the processing system (7; 9) determines spatial likelihood data representative of a likelihood of the received acoustic signal having been transmitted by the respective acoustic transmitter unit by comparing a time-of-flight range value with a geometric distance value, representative of a distance between the acoustic transmitter unit and the first position estimate.

Abstract: In a positioning system, a plurality of transmitter units (2, 3, 4, 5) transmit respective locating signals which are received at a mobile receiver unit (7). A processing system (7; 9) identifies the transmitter unit that transmitted each locating signal, and determines, for each transmitter unit, range data representative of a respective distance between the transmitter unit and the mobile receiver unit. The processing system determines a position estimate for the mobile receiver unit (7) by solving an optimisation problem that depends on i) the range data determined for the plurality of transmitter units, ii) data representative of the positions of the plurality of transmitter units in an environment (1), and iii) data representative of a position of a surface (1a, 1b, 1c, 1d, 1e; 601, 602) in the environment, by optimising for an objective function comprising a cost term that depends on a distance between the surface and the position estimate.

Abstract: The present disclosure relates to a location determination system that includes acoustic transmitting devices (104), location tags (112), and a wireless mesh network (106), where the wireless mesh network uses battery-powered devices. A location tag receives acoustic signals (e.g., ultrasound signals) from an acoustic transmitting device. Clocks from members of the wireless mesh network are synchronized by observation of clock pairings, each clock pair formed by respective clocks in a transmitting device that transmits a message and a receiving device that receives the message. By analyzing the observed clock pairings, a best fit between the clock pairings may be determined. After selecting a reference clock, an acoustic transmission schedule may be propagated to the respective acoustic transmitting device.

Abstract: 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.

Abstract: 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.

Abstract: A transmitter is disclosed. The transmitter includes a clock configured to generate one or more output clock signals. The transmitter further includes at least one frequency divider configured to generate a plurality of divided frequencies based on the one or more output clock signals, and a modulator. The transmitter also includes at least one antenna or transducer configured to transmit modulated data. The transmitter includes a memory configured to store instructions, and at least one processor configured to execute instructions performing operations including mapping data to a decimal code value of a plurality of decimal code values, converting the decimal code value to a shrinking base system, and selecting a set of frequencies among the plurality of divided frequencies based on the code value corresponding to the shrinking base system for the decimal code value. The modulator may be configured to modulate the decimal code value using the set of frequencies.

Abstract: The present disclosure relates to an acoustic position determination system that includes a mobile communication device and at least one base transmitter unit. The mobile communication device is configured to transmit and receive acoustic signals. Due to relative movements between the mobile communication device and the base transmitter unit, frequencies of the received signals shift due to Doppler effect. The mobile communication device is configured to compensate Doppler frequency shifts in the received acoustic signals prior to performing a deconvolution decoding process. The mobile communication device is further configured to compensate Doppler frequency shifts and perform deconvolution decoding process on acoustic signals received from multiple signal transmission paths.

Abstract: The present disclosure relates to an acoustic position determination system that includes a mobile communication device and at least one base transmitter unit. The mobile communication device is configured to identify a peak in the received signal, and to de-convolve the signal with all codes that are relevant to the area in which the signal is received. A joint likelihood that a potential code is correct is formed by determining a likelihood based on a signal parameter such as signal-to-noise ratio and a likelihood based on time-of arrival information.

Abstract: An apparatus (7) for down-converting a sampled signal comprises a processing system (206) configured to apply a mixing-and-combining operation repeatedly to successive sub-sequences of N input samples, X, representative of a signal and having an initial sampling rate, M, to generate a sequence of output samples, Y, having an output rate, T, lower than the initial sampling rate M. The sub-sequences of the N input samples, X, are spaced at intervals that correspond to the output rate M. The mixing-and-combining operation generates a respective output sample Y from each sub-sequence, where Y depends on a set of products of the input samples X of the sub-sequence with respective values derived from a periodic mixing signal having a mixing frequency.

Abstract: A receiving apparatus (7) that can estimate a motion-induced frequency shift in a received signal comprises a processing system (205) and a receiver (204) configured to receive a signal comprising one or more instances of a transmitted signal. The processing system (205) is configured to generate data representative of a plurality of impulse response functions by deconvolving the received signal with each of a plurality of templates representative of the transmitted signal shifted in frequency by a different respective frequency shift. The processing system (205) is further configured to evaluate a signal-to-noise measure for each of the plurality of impulse response functions, and to identify an impulse response function of the plurality of impulse response functions for which the signal-to-noise measure satisfies a peak criterion.

Abstract: In a positioning system, a plurality of transmitter units (2, 3, 4, 5) transmit respective transmitter-specific identification signals at intervals, which are received at a mobile receiver unit (7). A processing system (7; 9) identifies the transmitter unit that transmitted each received identification signal, and, for each signal, determines range data from time of arrival data and determines distance data from Doppler shift information. The range data and distance data are compared to determine range error data. A position estimate for the mobile receiver unit (7) is determined by solving an optimisation problem using range estimates determined for the plurality of transmitter units, weighted in dependence on the range error data.

Abstract: A communication device including a clock, a memory, and at least one processor is disclosed. The at least one processor is configured to execute instructions stored in the memory that cause the at least one processor to perform operations including receiving at least one message from a second communication device of a plurality of communication devices over a preconfigured time duration, determining a first local time of the clock of the communication device at which the at least one message from the second communication device is received, and determining a sync-time of the second communication device based on the at least one message from the second communication device. The operations include mapping the sync-time of the second communication device based on the first local time and the determined sync-time of the second communication device and adjusting a sync-time of the communication device based on the second local time.

Abstract: A method for finding door location in an automated way based on observations of people that are equipped with a device whose position is determined acoustically. By observing positioning transitions across internal structures such as walls, the location of doors can be automatically identified.

Abstract: An approach for the reliable detection of smartphones within vehicles. The cloud instructs two smartphones, which both detect an in-vehicle detection system, to report signals that reflect major sensor events, together with the timing using their respective clocks. By sending local clock timing and time-sensitive beacon content information to the cloud, the offset between the two smartphone clocks may be determined, thereby enhancing the reliability of the in-vehicle detection of the smartphones.

Abstract: Systems and methods of determining a location of a mobile computing device associated with a real-time locating system are provided. For instance, a mobile computing device can determine a first location of the mobile computing device. The mobile computing device can then receive acoustic-contextual data that is correlated with the first location of the mobile computing device. The acoustic-contextual data can include data associated with one or more transmitting devices, and data associated with an environment proximate the one or more transmitting devices. The mobile computing device can receive one or more signals from at least one of the one or more transmitting devices, and can determine a more accurate second location of the mobile computing device based at least in part on the acoustic-contextual data and the one or more received signals.