Determining a relative location of an object in an environment of a head-mountable device by performing a Wi-Fi round trip time (RTT) process to determine a location of the head-mountable device based on respective round-trip times for a plurality of access points or peer devices, using data generated by an inertial measurement unit as a basis for determining a pose of the head-mountable device, determining a location of a first object in an environment of the head-mountable device, and based at least in part on the location and pose of the head mountable device and the location of the first object, determining a relative location of the first object.

Disclosed herein are embodiments of a balloon-based positioning system and method. In one example embodiment, a system includes a group of at least three balloons deployed in the stratosphere and a control system configured for: determining a first set of spatial relationships relating to the group; determining a second set of spatial relationships relating to at least a portion of the group and to a reference point; determining a position of the reference point relative to the earth; using the determined first set, the determined second set, and the determined position of the reference point relative to the earth as a basis for determining a position of a target balloon in the group relative to the earth; and transmitting the determined position of the target balloon relative to the earth.

A method for tracking a device not actively sending patient data to a network of medical devices is disclosed. The method comprises the device giving a signal at a time interval; an active hub listening to the device at the time interval; the active hub storing information about the device; and the active hub continuing to listen at the time interval to the device until the device actively sends patient data, or until no more signals are heard from the device. A system for tracking a device of a network of medical devices is also disclosed. The network comprises a hub and at least one device. The at least one device is configured to give a signal to the hub at a time interval, if the at least one device does not actively send patient data. The hub is configured to listen at the time interval to any devices not actively sending patient data. The hub is configured to store information about any devices not actively sending patient data. The hub is configured to continue listening to any devices not actively sending patient data until all devices actively send patient data, or until no more signals are heard from any devices not actively sending patient data.

Methods and apparatus perform location estimation among peer-to-peer devices. For the various methods, data of several different types, such as received signal strength, timing measurements, time stamps, actual transmit power, etc., is measured, stored, and propagated within a peer-to-peer network to enable each device in the peer-to-peer network to calculate positioning coordinates for one or more devices having unknown positioning coordinates.

Methods and apparatus perform location estimation among peer-to-peer devices. For the various methods, data of several different types, such as received signal strength, timing measurements, time stamps, actual transmit power, etc., is measured, stored, and propagated within a peer-to-peer network to enable each device in the peer-to-peer network to calculate positioning coordinates for one or more devices having unknown positioning coordinates.

The present invention relates to a method for positioning multiple user equipments (UEs) by a base station in a wireless communication system supporting full-duplex communication and an apparatus therefor. More specifically, the present invention comprises: setting a unit distance on the basis of the magnitude of inter-device interference (IDI) with respect to a first UE; and establishing multiple boundaries around each of the multiple UEs and the base station according to relative distances on the basis of the unit distance and checking whether the boundaries overlap each other. Here, the relative distances indicate with respect to the multiple UEs, measured on the basis of the magnitude of inter-device interference (IDI).

Embodiments disclose a method and an apparatus for locating a wireless access point. M APs are deployed in a physical area, the M APs include N first reference APs and L to-be-located APs, and physical locations of the first reference APs and a first distance between any two first reference APs are determinate. The method includes obtaining a first electromagnetic wave signal received by a first to-be-located AP of the L to-be-located Aps, where the first electromagnetic wave signal includes an electromagnetic wave signal sent by each first reference AP. The method also includes determining a second distance between the first to-be-located AP and each first reference AP according to the first electromagnetic wave signal, and determining a physical location of the first to-be-located AP according to the first distance, the second distance, and the physical locations of all the N first reference APs.

The present invention relates to a position determination apparatus for the position determination of at least one RFID tag, comprising an RFID reader and a control device, wherein the control device is configured to transmit a radio signal by means of the RFID reader, said radio signal exciting an RFID tag to transmit a response signal. The position determination apparatus is movable to different locations from an original position and the control device is configured to transmit a respective radio signal at at least two different locations and to receive the respective response signal or the respective response signals.

An ordnance munition is included in an intelligent ordnance projectile delivery system and equipped with targeting and guidance systems that allow the ordnance munition to collaborate with other devices to intelligently select targets and/or to guide the ordnance munition to its selected target. The ordnance munition may be configured to generate first location information based on its determined approximate location, send the generated first location information to a wireless transceiver in proximity to the first ordnance munition, and receive location information from the wireless transceiver in response. The ordnance munition may determine its more precise location based on the received location information, and generating second location information based on the more precise location. The ordnance munition may change or adjust its flight path or trajectory based on the generated second location information.

A position estimation unit (2) comprising a first transceiver device (3) and a processing unit (10) that is arranged to repeatedly calculate time-of-flight (TOF) for radio signals (x.sub.1, x.sub.2, x.sub.3, x.sub.4, x.sub.5, x.sub.6) sent pair-wise between two transceivers among the first transceiver device (3) and at least two other transceiver devices (7, 8, 9); calculate possible positions for the transceiver devices (3, 7, 8, 9), which results in possible positions for each transceiver device (3, 7, 8, 9); and perform Multidimensional scaling (MDS) calculation in order to obtain relative positions of the transceiver devices (3, 7, 8, 9) in a present coordinate system. After two initial MDS calculations, between every two consecutive MDS calculations, the processing unit (10) is arranged to repeatedly perform a processing procedure comprising translation, scaling and rotation of present coordinate system such that a corrected present coordinate system is acquired. The processing procedure is arranged to determine the corrected present coordinate system such that a smallest change for the relative positions of the transceiver devices (3, 7, 8, 9) between the consecutive MDS calculations is obtained.