Methods and devices for, among other applications, locating an emitter, comprises an array of receivers configured in different angular positions about the array relative to a corresponding array location axis, to receive a signal from the emitter having at least one burst containing a train of pulses, and at least one processor configured to profile pulse count values at each receiver, from one receiver to another in the array in relation to their respective angular positions, to designate a maximum peak angular position associated with a maximum pulse count value, and to attribute the peak angular position to an angular emitter location.

A system may include one or more processors and a host unit installed in a support structure of a building, the host unit including a communication module configured to send or receive communication data with at least one or more additional host units installed in the building, where the one or more processors are configured to measure an attribute of the sent or received communication data and detect a presence of an object based on a threshold change in the measured attribute of the sent or received communication data between the host unit and the one or more additional host units. The attribute can be an angle-of-signal (AoS) arrival of the communication between the host unit and each of the one or more additional host units, where the threshold change in the measured attribute is a threshold change in the measured AoS arrival.

An apparatus estimates successive headings of a mobile device based on respective results of measurements by the mobile device on radio signal transmitted by a plurality of transmitters to obtain estimated headings (201). It computes a mean heading based on a predetermined number of the estimated headings and computing a standard deviation of the predetermined number of estimated headings (202). It determines whether the mean heading is to be considered valid based on the computed standard deviation of the estimated headings (203). Finally, it provides an indication of the mean heading as an indication of a current heading of the mobile device for use by a specific application only if the mean heading is determined to be considered valid (204).

A method includes: separately performing, by a requester, time measurement with a plurality of responders, and calculating a location of the requester based on a measurement result. A measurement result obtained by the requester by performing time measurement with each responder includes time stamps t1, t2, t3, and t4, where t1 is a time when the responder sends a measurement frame, t2 is a time at which the requester receives the measurement frame, t3 is a time when the requester sends an acknowledgement frame in response to the measurement frame, and t4 is a time when the responder receives the acknowledgement frame. The acknowledgement frame is sent by the requester after waiting for a randomly generated short interframe spacing after receiving a last symbol of the measurement frame. The randomly generated short interframe spacing is randomly generated within a specified fluctuation range of a nominal short interframe spacing.

Methods and systems associated with aligning reference frames used for tracking an object are disclosed. One embodiment disclosed herein is a method for generating a transform between a first and second frame of reference (FOR) using a sequence of heading values of the object in the first and second FOR. The method comprises providing instructions to orient the object towards one or more external positioning devices in an orienting sequence. The method also comprises obtaining the sequence of heading values of the object in the second FOR using an onboard sensor and obtaining a sequence of position values of the object in the first FOR in accordance with the orienting sequence and using the one or more external positioning devices. The method also comprises deriving the sequence of heading values of the object in the first FOR using the sequence of position values.

A method, apparatus, and augmented reality system comprising an active portable anchor used by an augmented reality device to display augmented reality information on a live view of an object. The active portable anchor is configured to output a current physical anchor position of the active portable anchor relative to an object.

A device uses a hybrid pose tracking system, whereby the hybrid pose tracking system includes both an EM pose tracking system and a secondary pose tracking system, such as a line-of-sight pose tracking system. The hybrid pose tracking system collects EM pose data from the EM tracking system indicating a relative pose between a transmitter and a receiver, and further collects from the secondary tracking system secondary pose data that is also indicative of the pose of either the transmitter or the receiver. The hybrid pose tracking system calculates a weighted combination (e.g., a weighted sum) of the EM pose data and the secondary pose data to generate a final pose for the device.

A fence system can determine positions and orientations of objects. The fence system may include fence associated with a fence network that has a plurality of fence nodes. The locations of the fence nodes and fence are defined in a fence coordinate system. A tracked object has a plurality of transient nodes. The fence network may determine the position and orientation of the tracked object based on estimated distances between at least two of the plurality transient nodes and at least two of the plurality of fence nodes. The system may also include a second fence associated fenced object that also has a plurality of transient nodes.

Described examples include light fixtures and/or radio frequency (RF) nodes located in a service volume provided with a mobile asset detection system. The RF nodes receive beacon signals transmitted by mobile assets within the service volume. The mobile asset detection system includes a processor, a transceiver and multi-element antenna array. The multi-element antenna array includes multiple discrete antenna elements that, in some examples, are arranged so that at least one of the discrete antenna elements is non-coplanar with the other discrete antenna elements of the antenna array. Using signal attribute values determined from a signal received via each of the respective discrete antenna elements, a three dimensional estimate of the location of the mobile assets in a service volume may be determined.

An RF position tracking system for wirelessly tracking the three-dimensional position of a tracked object. The tracked object has at least one mobile antenna and at least one inertial sensor. The system uses a plurality of base antennas which communicate with the mobile antenna using radio signals. The tracked object also incorporates the inertial sensor to improve position stability by allowing the system to compare position data from radio signals to data provided by the inertial sensor.