Patent application number | Description | Published |
20090243934 | Wireless time reference system and method - Instead of normalizing time reference of independent spatially-located clocks using a reference tag transmission from known location, the present invention uses an interarrival time interval between a pulse pair of UWB pulses as a timing metric. Thus, a method of synchronizing spatially-located clocks or normalizing time indications thereof comprises transmitting a UWB pulse pair, determining at first and second monitoring stations a respective count value indicative of a locally measured time interval between received pulse pairs, determining a ratio between clock counts of first and second monitoring stations, and utilizing the ratio to determine clock skew, e.g., a timing correction to be applied to respective local clocks of the monitoring stations. A corresponding system comprises a reference tag transmitter that transmits a pulse pair of UWB pulses to define a time reference interval, a first independent receiver that receives, the pulse pair to generate a first count value indicative an interarrival interval between the pulse pair, a second independent receiver that receives the pulse pair to similarly generate a second count value, and a processor hub responsive to the count values to determine a ratio corresponding to the ratio of respective clock frequencies of the first and second receiver clocks. Once the correction is applied, time-of-arrival information from object tag transmissions may be used to determine object location with sub-foot position accuracies. | 10-01-2009 |
20120086607 | WIRELESS TIME REFERENCE SYSTEM AND METHOD - Various methods and apparatuses that utilize a wireless time reference system are provided herein. One example method involves calibrating independent, spatially-located clocks of a geoposition system in order to geolocate an object having an associated object tag. The example method may include transmitting an RF pulse pair, receiving the pulse pair at multiple locations, utilizing respective frequencies of first and second spatially-located clocks to produce count values to effect measurement of an interarrival interval at each of multiple locations, determining a ratio of count values relative to said first and second spatially-located clocks, and utilizing said ratio to calibrate time indications of said clocks. Other related methods and apparatus are also provided. | 04-12-2012 |
20120188129 | EXTENSIBLE OBJECT LOCATION SYSTEM AND METHOD USING MULTIPLE REFERENCES - An ultra wideband (UWB) or short-pulse RF system is disclosed that can be used to precisely locate or track objects (such as personnel, equipment, assets, etc.) in real-time in an arbitrarily large, physically connected or disconnected, multipath and/or noisy environment. A system implementation includes multiple zones or groups of receivers that receives RF signals transmitted by one or more timing reference tags and one or more objects having associated object tags. Each zone or group may share a common receiver. By combining a multiple reference tag system with a virtual group of receivers, i.e., a zoning technique or system, a cost-effective system can be provided that offers scalability and flexibility to monitor a significantly expanded coverage area. | 07-26-2012 |
20150356332 | SYSTEMS, APPARATUS AND METHODS FOR VARIABLE RATE ULTRA-WIDEBAND COMMUNICATIONS - Systems, methods, apparatuses, and computer readable media are disclosed for providing variable blink rate ultra-wideband (UWB) communications. Some embodiments may provide for a radio frequency (RF) tag including a motion sensor, processing circuitry, and a UWB transmitter. The motion sensor may be configured to generate one or more motion data values indicating motion of the RF tag. The UWB transmitter may be configured to transmit blink data at variable blink rates. The processing circuitry may be configured to receive the one or more motion data values from the motion sensor, determine a blink rate for the UWB transmitter based on the one or more motion data values, and control the UWB transmitter to wirelessly transmit the blink data at the blink rate. In some embodiments, the RF tag may include a UWB receiver and the blink rate may be controlled remotely by a system. | 12-10-2015 |
20150358852 | RECEIVER PROCESSOR FOR BANDWIDTH MANAGEMENT OF A MULTIPLE RECEIVER REAL-TIME LOCATION SYSTEM (RTLS) - A method, apparatus and computer program product are provided for an active bandwidth management system for a tag target location system. A method is provided including determining a buffer fullness level for a receive buffer in a receiver in a set of one or more receivers, determining, by the processor hub, a set of buffer elements to be removed from the receive buffer in at least one of the receivers based on the buffer fullness level, and communicating to the one or more receivers to remove from the receive buffers the set of receive buffer elements identified by a sequence number. | 12-10-2015 |
20150358938 | Receiver Processor For Adaptive Windowing And High-Resolution TOA Determination In A Multiple Receiver Target Location System - The present invention provides methods for a high-resolution active RTLS tag location determination system that provides for <1 ns TOA accuracy and resolution and significantly reduces the channel effects of multipath interference, even in low SNR applications. To accomplish these objectives, the present invention provides for an iterative and adaptive windowing function in each of the receivers of a receiver grid that captures multiple reflections of multiple transmissions from each of the associated target RTLS tags. The adaptive windowing function is used in conjunction with an asynchronous transmit and receive clock function that effectively increases resolution of TOA detection to levels less than the minimum detection window width associated with each of the receivers in the receiver grid. | 12-10-2015 |