A method and apparatus for locating a target in a venue is described. A backend controller activates transmitters in a venue to send burst signals using a double symmetry configuration formed of a plurality of separate transmitter groups. The backend controller activates the transmitters into a second, different configuration for bursting. The resulting location signal information from each configuration is obtained by the backend controller, which then more accurately determines the location of the target in the venue.

A system and method for location positioning with steganographic encoded data streams in audible-frequency range audio is disclosed. The method comprises encoding, modulating and audio-hiding data streams into corresponding audible-frequency range steganographic audio signal; transmitting each audio signal by a corresponding loudspeaker, wherein each data stream includes the geographic location of the corresponding loudspeaker, a time stamp of transmission of periodic frames of the data stream and the like. In addition, a mobile device is used for: acquiring an audio signal that includes the transmitted audio signals; separating, demodulating and decoding the data streams therefrom; calculating the distance between the mobile device and each of the loudspeakers based on the time of flight between transmission and acquisition of each of the audio signals; and estimating the geographic location of the mobile device based on the distance between the mobile device and the loudspeakers and the geographic location of the loudspeakers.

Systems and methods for driver identification using vehicle approach vectors are disclosed. An example disclosed vehicle includes a plurality of beacons configured to connect to a first mobile device and a second mobile device. The example vehicle also includes a plurality of ultrasonic sensors. The example vehicle includes a driver identifier configured to predict trajectories for the first and second mobile devices based on information received from the plurality of beacons and the plurality of ultrasonic sensors, and determine which one of the mobile devices is associated with a driver based on the predicted trajectories.

Systems and methods for driver identification using vehicle approach vectors are disclosed. An example disclosed vehicle includes a plurality of beacons configured to connect to a first mobile device and a second mobile device. The example vehicle also includes a plurality of ultrasonic sensors. The example vehicle includes a driver identifier configured to predict trajectories for the first and second mobile devices based on information received from the plurality of beacons and the plurality of ultrasonic sensors, and determine which one of the mobile devices is associated with a driver based on the predicted trajectories.

A method and structure are disclosed for simultaneous detection of the relative positions between first and second members of each joint in a multiplicity of joints in a system. In the multiplicity of joints, as the relative positions between the first and second members of a joint change, a position-sensitive vibration source associated with that joint generates a vibration signal with a characteristic frequency spectrum. Vibration signals from the multiplicity of joints combine into a mixed vibration signal. This mixed vibration signal is detected and separated into individual characteristic frequency spectra by a vibration-detecting device to enable simultaneous monitoring of the positions of each of the joints in the multiplicity of j oints. Joints may be rotary, linear, or a combination of joint types.

A method and structure are disclosed for simultaneous detection of the relative positions between first and second members of each joint in a multiplicity of joints in a system. In the multiplicity of joints, as the relative positions between the first and second members of a joint change, a position-sensitive vibration source associated with that joint generates a vibration signal with a characteristic frequency spectrum. Vibration signals from the multiplicity of joints combine into a mixed vibration signal. This mixed vibration signal is detected and separated into individual characteristic frequency spectra by a vibration-detecting device to enable simultaneous monitoring of the positions of each of the joints in the multiplicity of j oints. Joints may be rotary, linear, or a combination of joint types.

In order to enable more accurate estimation of an interference area for communication using an acoustic wave under water, an interference area information output apparatus, which is connected to a base station performing wireless communication using an acoustic wave with a wireless communication apparatus being present under water, estimates an interference area being a range where an interference wave possibly interferes with the wireless communication, based on position information relating to an interference source emitting the interference wave being an acoustic wave possibly interfering with the wireless communication, topographic information relating to a periphery of the interference source, and sound speed distribution indicating a sound speed at each location under water in the periphery of the interference source, and outputs interference area information including information relating to the interference area.

In order to enable more accurate estimation of an interference area for communication using an acoustic wave under water, an interference area information output apparatus, which is connected to a base station performing wireless communication using an acoustic wave with a wireless communication apparatus being present under water, estimates an interference area being a range where an interference wave possibly interferes with the wireless communication, based on position information relating to an interference source emitting the interference wave being an acoustic wave possibly interfering with the wireless communication, topographic information relating to a periphery of the interference source, and sound speed distribution indicating a sound speed at each location under water in the periphery of the interference source, and outputs interference area information including information relating to the interference area.

Various presence detection techniques are disclosed. In some embodiments, a system comprises a signal generator configured to generate a signal that includes a plurality of selected frequencies that are selected from among a set of candidate frequencies, wherein inclusion or exclusion of each candidate frequency in the signal encodes a bit of information and wherein the encoded information comprises a store identifier that identifies a retail store; and a transmitter configured to transmit the signal within the retail store; wherein presence of a device in the retail store is determined in response to reception of the signal at the device and extraction of the store identifier from the received signal by decoding the received signal.

Spatially located ultrasound beacons are provided in known locations within a distributed communication system. The ultrasound beacons are configured to emit ultrasound pulses that can be received by client devices in ultrasound communication range of the beacons. The client devices are configured to analyze the received ultrasound pulses from the beacons to determine their time-difference of arrival and as a result, their location(s) within the distributed communication system. The client devices comprise inertial navigation systems (INS) that calculate client device location as the client device moves, and when received ultrasound signals are below a predefined threshold.