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.

Systems and methods for navigating an aerial vehicle are provided. One example aspect of the present disclosure is directed to a method for navigating an aircraft. The method includes receiving, by one or more processors, one or more first geographic coordinates via an interface configured to receive geographic coordinates from a satellite transmission. The method includes receiving, by the one or more processors, one or more second geographic coordinates via an interface configured to receive geographic coordinates from a ground transmission. The method includes determining, by the one or more processors, that the one or more first geographic coordinates and the one or more second geographic coordinates are inconsistent. The method includes updating, by the one or more processors, a flight plan using the one or more second geographic coordinates when the one or more first geographic coordinates are inconsistent with the one or more second geographic coordinates.

Systems and methods for navigating an aerial vehicle are provided. One example aspect of the present disclosure is directed to a method for navigating an aircraft. The method includes receiving, by one or more processors, one or more first geographic coordinates via an interface configured to receive geographic coordinates from a satellite transmission. The method includes receiving, by the one or more processors, one or more second geographic coordinates via an interface configured to receive geographic coordinates from a ground transmission. The method includes determining, by the one or more processors, that the one or more first geographic coordinates and the one or more second geographic coordinates are inconsistent. The method includes updating, by the one or more processors, a flight plan using the one or more second geographic coordinates when the one or more first geographic coordinates are inconsistent with the one or more second geographic coordinates.

A beacon transmitter including a wireless transceiver and an electronic controller coupled to the wireless transceiver. The electronic controller is configured to repeatedly transmit, via the wireless transceiver, a first beacon signal through a first number of transmission repetitions spaced at a first repeat interval, and receive an acknowledgement signal via the wireless transceiver. The electronic controller is also configured to stop transmission of the first beacon signal for a first predetermined amount of time based on receipt of the acknowledgement signal, determine that the first predetermined amount of time has expired, and resume repeatedly transmitting, via the wireless transceiver, the first beacon signal in response to determining that the predetermined amount of time has expired.

A tracking system determines a location of a tracking device associated with a user using one or more access points at the location. Each access point at the location is configured to detect and couple with the tracking device when the tracking device is within a communicative range of the access point. An access point provides updates on the tracking device's presence, as well as the tracking device's arrival to and departure from the communicative range of the access point, to a tracking server. The tracking server determines, from these updates, whether the tracking device is at the location. The user may be notified, via a mobile device, of the tracking device's location.

A tracking system determines a location of a tracking device associated with a user using one or more access points at the location. Each access point at the location is configured to detect and couple with the tracking device when the tracking device is within a communicative range of the access point. An access point provides updates on the tracking device's presence, as well as the tracking device's arrival to and departure from the communicative range of the access point, to a tracking server. The tracking server determines, from these updates, whether the tracking device is at the location. The user may be notified, via a mobile device, of the tracking device's location.

Provided is a system 10 for remote activation of an emergency radio beacon by a Search and Rescue (SAR) party, the system 10 comprising a controller 12 operatively arranged in signal communication with an emergency radio beacon 14, a positioning module 16 arranged in signal communication with the controller 12 and configured to operatively provide spatial positioning data to the controller 12, and a receiver 18 arranged in signal communication with the controller 12 and configured to operatively receive an activation signal 20. The controller 12 is configured to activate the beacon 14 upon receipt of the activation signal 20 and to provide the spatial positioning data of a potentially lost or distressed party to the beacon 14 for transmission along with an emergency signal 22.

Provided is a system 10 for remote activation of an emergency radio beacon by a Search and Rescue (SAR) party, the system 10 comprising a controller 12 operatively arranged in signal communication with an emergency radio beacon 14, a positioning module 16 arranged in signal communication with the controller 12 and configured to operatively provide spatial positioning data to the controller 12, and a receiver 18 arranged in signal communication with the controller 12 and configured to operatively receive an activation signal 20. The controller 12 is configured to activate the beacon 14 upon receipt of the activation signal 20 and to provide the spatial positioning data of a potentially lost or distressed party to the beacon 14 for transmission along with an emergency signal 22.

A system and methods for estimating the location of a mobile device are disclosed. In accordance with one embodiment, a mobile device receives, at a first time t.sub.1, a wireless electromagnetic signal, where the wireless electromagnetic signal comprises a first identifier that identifies a first beacon that transmitted the wireless electromagnetic signal. The mobile device receives, at a second time t.sub.2, t.sub.2>t.sub.1, an ultrasound signal lacking an identification of the source of the ultrasound signal. A time difference of arrival (TODA) t.sub.2−t.sub.1 is compared to a maximum TDOA. A location of the mobile device is estimated based on the TDOA only when the TDOA is less than or equal to the maximum TDOA.

Disclosed is a beacon-based positioning system. A beacon position in which a beacon is installable is defined in a target space, and a path loss model of radio frequency (RF) signals between all beacon positions and all observation positions of a scanner is determined. Among all possible installation plans for the beacon positions, an installation plan in which different beacon signals, whose RSSIs calculated using the path loss model have significant values, are received in a number greater than or equal to a minimum reference number and a total number of the beacons installed is minimum is determined as an optimal installation plan. The optimization problem of determining the optimal installation plan may be expressed by binary linear programming.