The purpose is to provide a compact circularly polarized antenna while obtaining desired antenna characteristics. The circularly polarized antenna may include an antenna substrate formed with a flat film conductor configured to transmit and receive a circularly polarized wave, and a cavity formed in a surface of the antenna substrate opposite from a radiation surface. The cavity may at least partially overlap with the flat film conductor when seen in a depth direction of the cavity. The length of the cavity in at least one direction may be shorter than half of a wavelength of the circularly polarized wave.

A system includes a locatable glove and a pose determination device. The locatable glove includes a glove body worn over a hand of a user, and a plurality of positioning transponders. The positioning transponders are coupled to the glove body at various positions on the glove body, and each re-radiates a received signal, the re-radiated signal unique to the positioning transponder. The pose determination device includes a plurality of antennas and a controller. The antennas are each configured to receive the unique signals re-radiated by the positioning transponders. The antennas are physically separated from each other. The controller is communicatively coupled to the plurality of antennas, and is configured to determine, for each of the received unique signals, a location of the position on the locatable glove of the positioning transponder corresponding to the unique signal.

Methods and apparatus for determining a location and an orientation of a smart device via wireless communication. The location and direction of the smart device may be used to generate a data query and/or submit information into a data storage, referencing a time, place and direction of the smart device.

The invention relates to a method for determining by a direction finder (DF) the direction to a Target, which comprises (a) providing an antenna at the DF, and an array of antennas at the Target; (b) providing a compass at each of the DF and the Target, for determining the azimuth of the DF Heading and of the Target Heading, respectively, with respect to the North; (c) providing at the DF a look-up table which describes n antenna patterns, one per Transmission Mode that may be used respectively at the Target; (d) sequentially performing x Transmission Modes from the Target, each time using another pair of antennas, and during each of the Transmission Modes intentionally, and in a controlled manner attenuating a reception signal at the DF until a loss of communication, and recording the respective attenuation levels; (e) based on the x recorded attenuations levels and the look up table, determining by the DF the direction from the Target to the DF; and (f) receiving at the DF the azimuth of the Target, and based on (i) the determined direction from the Target to the DF (ii) azimuth of the Target; and (iii) azimuth of the DF; calculating by the DF the direction from the DF to the Target.

A system and method is disclosed for measuring time of flight to an object. A transmitter transmits an electromagnetic signal and provides a reference signal corresponding to the electromagnetic signal. A receiver receives the electromagnetic signal and provides a response signal corresponding to the received electromagnetic signal. A detection circuit is configured to determine a time of flight between the transmitter and the receiver based upon the reference signal and the response signal.

Head-mounted augmented reality (AR) devices can track pose of a wearer's head to provide a three-dimensional virtual representation of objects in the wearer's environment. An electromagnetic (EM) tracking system can track head or body pose. A handheld user input device can include an EM emitter that generates an EM field, and the head-mounted AR device can include an EM sensor that senses the EM field. EM information from the sensor can be analyzed to determine location and/or orientation of the sensor and thereby the wearer's pose. The EM emitter and sensor may utilize time division multiplexing (TDM) or dynamic frequency tuning to operate at multiple frequencies. Voltage gain control may be implemented in the transmitter, rather than the sensor, allowing smaller and lighter weight sensor designs. The EM sensor can implement noise cancellation to reduce the level of EM interference generated by nearby audio speakers.

An illustrative example method of tracking a detected object comprises determining that a tracked object is near a host vehicle, determining an estimated velocity of the tracked object, and classifying the tracked object as frozen relative to stationary ground when the estimated velocity is below a preselected object threshold and a speed of the host vehicle is below a preselected host threshold.

A method performed by a first communication device operating in a wireless communications network. The first communication device obtains a set of correspondences associating: i) each set (.sub.i) of a plurality of sets of antenna weights (.sub.1 . . . .sub.i) having been sent by a third communication device in response to having received a respective set (RSs.sub.i) of a plurality of sets of radio signals (RSs.sub.1 . . . RSs.sub.i) from a set of antenna ports in a second communication device, with ii) a respective direction of transmission (d.sub.i) between the second communication device and the third communication device. The respective direction is relative to an orientation (.sub.i) of the second communication device. The respective direction of transmission (d.sub.i) is a selected direction of transmission (d.sub.i,i). The first communication device then initiates transmission of a new radio signal, based on the obtained set of correspondences.

A method of determining the location of the first object (10) may include receiving signals at a second object (20) from a plurality of measurement points (11) on the first object (10), estimating locations of the plurality of measurement points (11) on the first object (10), determining an estimate of a location of the first object (10), determining a first measurement of an orientation of the first object (10) based on the estimating of the locations of the plurality of measurement points (11) on the first object (10), and determining a second measurement of the orientation of the first object (10) based on measurements by an orientation sensor (12) on the first object (10). The method may include estimating an error of the estimate of the location of the first object (10) based on a difference between the first and second orientation measurements and adjusting a movement of the second object (20) based on the estimated error.

Techniques and apparatuses are described that implement a smartphone-based radar system capable of detecting user gestures using coherent multi-look radar processing. Different approaches use a multi-look interferometer or a multi-look beamformer to coherently average multiple looks of a distributed target across two or more receive channels according to a window that spans one or more dimensions in time, range, or Doppler frequency. By coherently averaging the multiple looks, a radar system generates radar data with higher gain and less noise. This enables the radar system to achieve higher accuracies and be implemented within a variety of different devices. With these accuracies, the radar system can support a variety of different applications, including gesture recognition or presence detection.