Method for iterative target location in a multiple receiver target location system
First Claim
1. A method for determining target location in a multiple receiver target location system, the multiple receiver target location system including a plurality of location tags each associated with a respective target, a plurality of receivers, and a central processor, the method comprising:
- receiving, from the receivers, time of arrival (TOA) data associated with location tag transmissions;
determining a set of the receivers based on the received TOA data;
calculating a tag location estimate for the set of the receivers by applying a minimizing function to a subset of the TOA data corresponding to the set of the receivers;
determining a data quality indicator (DQI) for the tag location estimate; and
when the DQI for the tag location estimate does not meet a DQI threshold;
determining, for the subset of the TOA data, impacts of respective delays on the minimizing function;
removing, based on the impacts of the respective delays, one of the receivers from the set of the receivers; and
after removing the one of the receivers, recalculating the tag location estimate for the set of the receivers.
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Accused Products
Abstract
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.
194 Citations
21 Claims
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1. A method for determining target location in a multiple receiver target location system, the multiple receiver target location system including a plurality of location tags each associated with a respective target, a plurality of receivers, and a central processor, the method comprising:
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receiving, from the receivers, time of arrival (TOA) data associated with location tag transmissions; determining a set of the receivers based on the received TOA data; calculating a tag location estimate for the set of the receivers by applying a minimizing function to a subset of the TOA data corresponding to the set of the receivers; determining a data quality indicator (DQI) for the tag location estimate; and when the DQI for the tag location estimate does not meet a DQI threshold; determining, for the subset of the TOA data, impacts of respective delays on the minimizing function; removing, based on the impacts of the respective delays, one of the receivers from the set of the receivers; and after removing the one of the receivers, recalculating the tag location estimate for the set of the receivers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer program product comprising at least one non-transitory computer-readable storage medium having computer-executable program code portions stored therein, the computer-executable program code portions comprising program code instructions configured to:
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receive, from a plurality of receivers, time of arrival (TOA) data associated with location tag transmissions; determine a set of the receivers based on the received TOA data; calculate a tag location estimate for the set of the receivers by applying a minimizing function to a subset of the TOA data corresponding to the set of the receivers; determine a data quality indicator (DQI) for the tag location estimate; and when the DQI for the tag location estimate does not meet a DQI threshold; determine, for the subset of the TOA data, impacts of respective delays on the minimizing function; remove, based on the impacts of the respective delays, one of the receivers from the set of the receivers; and after removing the one of the receivers, recalculate the tag location estimate for the set of the receivers. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus for determining target location in a multiple receiver target location system, the multiple receiver target location system including a plurality of location tags each associated with a respective target and a plurality of receivers, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the processor, cause the apparatus to at least:
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receive, from a plurality of receivers, time of arrival (TOA) data, associated with location tag transmissions; determine a set of the receivers based on the received TOA data; calculate a tag location estimate for the set of receivers by applying a minimizing function to a subset of the TOA data corresponding to the set of the receivers; determine a data quality indicator (DQI) for the tag location estimate; and when the DQI for the tag location estimate does not meet a DQI threshold; determine, for the subset of the TOA data, impacts of respective delays on the minimization function; remove, based on the impacts of the respective delays, one of the receivers from the set of the receivers; and after removing the one of the receivers, recalculate the tag location estimate for the set of the receivers. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification