An exit obstruction warning device monitoring an exit door and broadcasting an alert regarding an obstruction blocking the exit door is provided. The exit obstruction warning device includes a sensor, a processing module, and an output module. The sensor monitors the exit door for the obstruction. The output module broadcasts an alarm notification in response to the obstruction. The processing module receives a signal from the sensor that describes the obstruction blocking the exit door. The processing module processes the signal and operates the output module based on the signal.

Methods and apparatus for verifying respective positions of Nodes based upon wireless communications between Nodes included in an array. Values for variables derived from multiple wireless transmissions between Nodes are aggregated, and a position of a particular Node may be determined based upon multiple data sets generated by multiple communications between disparate Nodes. In addition, the presence of an obstacle to wireless communication between some Nodes may be derived from the data sets. A user interface may provide a pictorial view of positions of all or some Nodes in an array, as well as a perceived obstruction.

A tracking system can provide configuration instructions to an electronic device based on user presence. The tracking system can determine a user's location relative to a geographic boundary surrounding a geographic area associated with the user. Depending on the user's location, the tracking system may send instructions to configure an electronic device to send a notification or change the operating mode of the electronic device in response to the user's presence. The electronic device may be a scanning device that is configured to have a higher or lower scanning frequency, depending on the presence or absence of the user relative to the scanning device.

A tracking system can provide configuration instructions to an electronic device based on user presence. The tracking system can determine a user's location relative to a geographic boundary surrounding a geographic area associated with the user. Depending on the user's location, the tracking system may send instructions to configure an electronic device to send a notification or change the operating mode of the electronic device in response to the user's presence. The electronic device may be a scanning device that is configured to have a higher or lower scanning frequency, depending on the presence or absence of the user relative to the scanning device.

An antenna receiver has antenna elements that are arranged in an array and spaced apart from each other at a distance greater than one-half wavelength of the highest operating frequency of a signal that is to be detected by the antenna receiver. The antenna receiver has geolocation logic that uses the inter-element phase difference measurements to obtain a location of the signal source. The change in the inter-element phase differences enables the elements to be spaced apart at great distances, which is beneficial for the physical construction of the platform, as the elements may be easily placed at convenient locations for conformal aerodynamic properties.

An antenna receiver has antenna elements that are arranged in an array and spaced apart from each other at a distance greater than one-half wavelength of the highest operating frequency of a signal that is to be detected by the antenna receiver. The antenna receiver has geolocation logic that uses the inter-element phase difference measurements to obtain a location of the signal source. The change in the inter-element phase differences enables the elements to be spaced apart at great distances, which is beneficial for the physical construction of the platform, as the elements may be easily placed at convenient locations for conformal aerodynamic properties.

Disclosed are techniques for wireless communication. In an aspect, a base station performs one or more angle-based measurements in a first coordinate system, determines whether to report, to a positioning entity, the one or more angle-based measurements in a local coordinate system (LCS) or a global coordinate system (GCS), and reports the one or more angle-based measurements to the positioning entity in the LCS or the GCS based on the determination. In an aspect, a positioning entity receives, from a base station, one or more angle-based measurements in an LCS of the base station or a GCS, determines whether the one or more angle-based measurements are in the LCS or the GCS, and processes the one or more angle-based measurements based on the determination.

A positioning and tracking system is disclosed. The positioning and tracking system includes positioning sensors disposed in a space, wherein the positioning sensors are all movable and all have functions of sensing distance, angle and time, and the positioning sensors communicate with each other to sense relative distances, relative angles and relative times between every two positioning sensors of the positioning sensors. when at least one of the positioning sensors moves in the space, the positioning sensors re-communicate with each other to instantly update the relative distances, the relative angles and the relative times between every two positioning sensors of the positioning sensors.

A positioning and tracking system is disclosed. The positioning and tracking system includes positioning sensors disposed in a space, wherein the positioning sensors are all movable and all have functions of sensing distance, angle and time, and the positioning sensors communicate with each other to sense relative distances, relative angles and relative times between every two positioning sensors of the positioning sensors. when at least one of the positioning sensors moves in the space, the positioning sensors re-communicate with each other to instantly update the relative distances, the relative angles and the relative times between every two positioning sensors of the positioning sensors.

A method according to an embodiment includes receiving UWB data indicative of a distance of a mobile device relative to the access control device and a SNR of signals received by a plurality of UWB antennas, inferring a side of the passageway at which the mobile device is located based on the distance of the mobile device relative to the access control device and also based on the SNR of the signals, estimating a travel time of the mobile device to the passageway based on the UWB data if the inferred side of the passageway based on the distance of the mobile device is different from the side of the passageway inferred based on the SNR of the signals, and determining the side of the passageway at which the mobile device is located to be an unsecure side of the passageway if the travel time exceeds a predefined threshold time.