A novel solution to generate an optimal spatial placement map of Radio Frequency (RF) beacons, such as Bluetooth Low Energy (BLE) beacons, which can be used for indoor localization. A described embodiment solves for both generating optimal number of beacons required in a given environment and optimizing their location. The solution also incorporates behavior of RF signal due to various environmental factors such as signal reflection and absorption due to static and dynamic obstacles. In one embodiment, the framework is built upon Genetic Algorithm (GA) for optimization of beacon placement. The experimental results achieved using one implementation of the described method reduced the number of beacons by 50% as compared to beacons placed using expert knowledge. Furthermore, the overall localization error increased by 0.4 m when the results using the RF/BLE map generated by the described system were compared with the RF/BLE map generated using expert knowledge.

Embodiments provide a positioning method, an assistant site, and a system, to improve positioning accuracy of a mobile terminal. The method according to the embodiments of the present invention includes: generating, by an assistant site, a downlink assisted positioning signal; and sending, by the assistant site, the downlink assisted positioning signal to a mobile terminal. The downlink assisted positioning signal can enable a base station to determine position information of the mobile terminal based on a measurement result obtained by the mobile terminal by measuring the downlink assisted positioning signal.

Disclosed is a system, method, mobile communication device and one or more computer programs for a monitoring system. In one aspect, the system includes a plurality of transmitters, each transmitter having associated therewith a reflector antenna configured to substantially reflect signal transmission toward a detection area; and a mobile device configured to: receive transmitter signals from at least two transmitters from the plurality of transmitters; and determine that the mobile device is located within the detection area based on received signal strengths of the at least some of the transmitter signals.

A reach and placement tool includes an eyepiece, an orientation sensor, a distance sensor, and a controller. The controller is configured to obtain a distance value and an orientation from the distance sensor and the orientation sensor when the reach and placement tool is directed towards a point of interest at a particular location. The controller is also configured to determine a coordinate of the point of interest using the distance value and the orientation, and compare the coordinate of the point of interest to a reach envelope to determine if the point of interest is within range of a particular reach apparatus.

A modular backpack system includes a personal floatation harness having an automatic inflator mechanism and pack attachment features; and a plurality of pack modules selectively attachable to the pack attachment features to form a floatation-enhanced backpack. Each one of the plurality of pack modules may further include a different arrangement for accommodating accessories. For example, the different arrangements may include arrangements having different compartments. Other arrangements may have different attachment features. The different attachment features may include different lash points. The backpack module may be one taken from the list of: a pack adapted for kayaking with a waterproof compartment and lash points for ready access to accessories; a pack adapted for sailing with waterproof and non-waterproof compartments; a pack adapted for hiking with multiple compartments for tools and supplies; and a pack adapted for everyday carry (EDC) having multiple quick-access compartments for carrying everyday tools.

User devices (1-4) are each provided with a data connection (20) to a remote server (30) and a beacon transceiver. Device (2) is operable to actively transmit beacon signals including its unique beacon identification code for a limited period. During active transmissions by device (2), devices (1 & 3) are within range of the transmissions and are operable to extract the beacon identification code of the transmitting device (2) and thus directly infer that they are in proximity to the transmitting device (2). The receiving devices (1, 3) communicate with server (30) their own unique beacon identification code and the received beacon identification code of the transmitting device (2). In response, the server (30) communicates details of the transmitting device (2) to the receiving devices (1, 3) and the beacon identification codes of the receiving devices (1, 3) to the transmitting device (2). The transmitting device (2) is thus able to infer the proximity of the receiving devices (1, 3) without the receiving devices (1, 3) having to transmit any beacon signals.

Systems and methods for determining a location of one or more user equipment (UE) in a wireless system can comprise receiving reference signals via a location management unit having two or more co-located channels, wherein the two or more co-located channels are tightly synchronized with each other and utilizing the received reference signals to calculate a location of at least one UE among the one or more UE. Embodiments include multichannel synchronization with a standard deviation of less than or equal 10 ns. Embodiments can include two LMUs, with each LMU having internal synchronization, or one LMU with tightly synchronized signals.

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.

One or more surfaces within a facility are equipped with devices having several segments, each segment with an antenna. Segments may be grouped together into a cluster. Each segment within a cluster is associated with a particular timeslot. A transmitter at the device transmits on a specific frequency. During the particular timeslot for that segment, a signal at the specific frequency is transmitted and radiated from the antenna for that segment. An object electromagnetically couples to one or more antennas of the device, acting as a signal path for the signal. A receiver in a second segment detects the signal, and information about the timeslot for the signal and relative signal strength is generated. By using this information, a location and path of the object may be determined. Receivers in shelves may also be used to facilitate disambiguation of one user from another when interacting with items on those shelves.

The subject matter described herein includes methods and systems for performing physical measurements using radio frequency (RF) signals. According to one embodiment of the present invention, a method is disclosed for determining the distance between a first radio device and a second radio device. The method includes transmitting a radio frequency (RF) signal from the first radio device and receiving the RF signal by the second radio device. The method further includes a determining a carrier frequency of the RF signal and determining a slope of a carrier phase versus the carrier frequency corresponding to a rate of change of the carrier phase with the carrier frequency. The method also includes determining a physical distance between the first radio device and the second radio device based on the slope; wherein the physical distance is proportional to the slope plus an integer ambiguity term and a bias term.