Zebra Technologies Corporation

Zih Corporation

Chang Wang

Edward Anthony Richley

Belinda Turner

Aitan Ameti

An example method includes receiving environmental data from a plurality of receivers; calculating, using a processor, an environmental offset based on the environmental data, wherein the environmental offset is operable to adjust a reference phase offset; and dynamically adjusting the environmental offset in response to a detected change in the environmental data.

Method, apparatus, and computer program product for real time location system referencing in physically and radio frequency challenged environments

An disclosed method includes receiving, from receivers, TOA data associated with location tag transmissions; determining a first set of the receivers based on the received TOA data; calculating a first tag location estimate for the first set of the receivers by applying a minimizing function to a first set of the TOA data corresponding to the first set of the receivers; determining a first data quality indicator (DQI) for the first tag location estimate; and when the first DQI for the first tag location estimate does not meet a threshold: determining, for the first set of the TOA data, impacts of respective delays on the minimizing function; determining, based on the impacts of the respective delays on the minimizing function, a second set the receivers different from the first set of the receivers; and calculating a second tag location estimate for the second set of the receivers.

Method for iterative target location in a multiple receiver target location system

Systems, methods, apparatuses, and computer readable media are disclosed for improving, in some examples, reference in a location system. In one embodiment, a method is provided comprising: receiving reference tag blink data from a plurality of receivers; calculating, using a processor, a reference phase offset between the plurality of receivers; and generating a suspended reference phase offset table, wherein a suspended reference phase offset table is generated by causing the reference phase offset to be stored in a memory for later tag location calculations.

A disclosed example apparatus receives a tag transmission signal from a tag at a receiver, wherein the tag transmission signal comprises a series of pulses; determines a coarse estimate of a time-of-arrival (TOA) of the tag transmission signal based on a detection of a pulse of the series of pulses in an adjustable coarse timing window, wherein the coarse estimate is based on a plurality of coarse timing windows; determines a fine estimate of the TOA based on a detection of the pulse in at least one of a parallel set of fine timing windows; and determines a sub-window resolution of the TOA based on at least one detection transition between consecutive fine receiver windows of at least one of a plurality of pulses and a weighted average of the TOA for each pulse of the series of pulses.

Receiver processor for adaptive windowing and high-resolution TOA determination in a multiple receiver target location system

The present invention provides methods for an active RFID tag target location system that provides for an iterative recalculating of a target location estimate by successively testing receiver TOA and DTOA error measurements and discarding outlier receivers. The present invention works to reduce the erratic effects that multipath channel interference and random noise play in target location systems due to incorrect identification of the main pulse of the transmit signal. In addition to providing for a greater accuracy and consistency in a TOA-based target location system, the method also provides for an opportunity to reduce a transmission bandwidth associate with the TOA transmission by the multiple receivers. The method may be considered a post-processing element, as the determination of TOA and DTOA may require a real-time calculation, where the timing constraints for the ensuing target location estimate may be less severe.

The present invention provides methods for a high-resolution active RTLS tag location determination system that provides for &#x3c;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.

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.

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Boyds, MD, United States of America

Chang Wang