Local positioning systems and methods
First Claim
Patent Images
1. A local positioning system, comprising:
- at least one node configured to track a mobile tag, the at least one node configured to determine a plurality of sample values, each of the sample values indicative of a respective location of the tag relative to the at least one node and based on at least one signal communicated with the tag, the at least one node having a filter configured to combine the sample values via a filtering algorithm thereby providing an estimate indicative of a current location of the tag, the at least one node further configured associate each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value,wherein the filtering algorithm is based on the filter parameter values associated with the sample values, wherein for one of the sample values the at least one node is configured to perform a comparison between the one sample value and an estimate indicative of a previous location of the tag, and wherein the filter parameter value associated with the one sample is based on the comparison.
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Abstract
A local positioning system uses at least one node to track a location of a mobile tag. The system measures flight times of signals communicated between the node and the tag to determine values indicative of the range of the tag from the node. If desired, the values may be filtered in an effort to increase the accuracy of the range estimation. As an example, a Kalman filtering algorithm may be used. Multiple antennas are used at both the node and the tag to provide more accurate range estimates and to determine when the tag is entering a dead zone where signals are blocked or attenuated by obstacles.
31 Citations
27 Claims
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1. A local positioning system, comprising:
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at least one node configured to track a mobile tag, the at least one node configured to determine a plurality of sample values, each of the sample values indicative of a respective location of the tag relative to the at least one node and based on at least one signal communicated with the tag, the at least one node having a filter configured to combine the sample values via a filtering algorithm thereby providing an estimate indicative of a current location of the tag, the at least one node further configured associate each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value, wherein the filtering algorithm is based on the filter parameter values associated with the sample values, wherein for one of the sample values the at least one node is configured to perform a comparison between the one sample value and an estimate indicative of a previous location of the tag, and wherein the filter parameter value associated with the one sample is based on the comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A local positioning system, comprising:
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at least one node configured to track a mobile tag, the at least one node configured to determine a plurality of sample values, each of the sample values indicative of a respective location of the tag relative to the at least one node and based on at least one signal communicated with the tag, the at least one node having a filter configured to combine the sample values via a filtering algorithm thereby providing an estimate indicative of a current location of the tag, the at least one node further configured associate each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value, wherein the filtering algorithm is based on the filter parameter values associated with the sample values, wherein the at least one node is configured to perform a comparison between a threshold and a value indicative of a sensed movement of the tag, and wherein the at least one node is configured to update the filter based on the comparison. - View Dependent Claims (9)
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10. A local positioning system, comprising:
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at least one node configured to track a mobile tag, the at least one node configured to determine a plurality of sample values, each of the sample values indicative of a respective location of the tag relative to the at least one node and based on at least one signal communicated with the tag, the at least one node having a filter configured to combine the sample values via a filtering algorithm thereby providing an estimate indicative of a current location of the tag, the at least one node further configured associate each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value, wherein the filtering algorithm is based on the filter parameter values associated with the sample values, wherein the at least one node, for one of the sample values, is configured to determine a plurality of distance measurement values, each of the plurality of distance measurement values indicative of a measured distance between the at least one node and the tag, and wherein the at least one node is configured to perform a comparison of the plurality of distance measurement values and to select, based on the comparison, one of the distance measurement values as the one sample value to be filtered by the filter. - View Dependent Claims (11, 12, 13)
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14. A local positioning system, comprising:
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at least one node configured to track a mobile tag, the at least one node configured to determine a plurality of sample values, each of the sample values indicative of a respective location of the tag relative to the at least one node and based on at least one signal communicated with the tag, the at least one node having a filter configured to combine the sample values via a filtering algorithm thereby providing an estimate indicative of a current location of the tag, the at least one node further configured associate each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value, wherein the filtering algorithm is based on the filter parameter values associated with the sample values, wherein the at least one node is configured to determine a value indicative of a number of lost antenna paths between the at least one node and the tag, and wherein the at least one node configured to determine whether the tag is in a dead zone based on the value indicative of the number of lost antenna paths. - View Dependent Claims (15, 16)
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17. A local positioning method, comprising the steps of:
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determining a plurality of sample values, each of the sample values indicative of a respective location of a mobile tag and based on at least one signal communicated with the tag; associating each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value; comparing one of the sample values and an estimate indicative of a previous location of the tag; determining the filter parameter value associated with the one sample value based on the comparing step; filtering the sample values thereby providing an estimate indicative of a current location of the tag, wherein the filtering step comprises the step of combining the sample values via a weighted filtering algorithm based on the associated filter parameter values; and storing the estimate in memory. - View Dependent Claims (18, 19, 20)
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21. A local positioning method, comprising the steps of:
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determining a plurality of sample values, each of the sample values indicative of a respective location of a mobile tag and based on at least one signal communicated with the tag; associating each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value; filtering the sample values thereby providing an estimate indicative of a current location of the tag, wherein the filtering step comprises the step of combining the sample values via a weighted filtering algorithm based on the associated filter parameter values; storing the estimate in memory; determining a plurality of distance measurement values, each of the plurality of distance measurement values indicative of a respective location of the tag; comparing the plurality of distance measurement values; and selecting, based on the comparing step, one of the plurality of distance measurement values as one of the sample values to be filtered in the filtering step. - View Dependent Claims (22, 23, 24)
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25. A local positioning method, comprising the steps of:
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determining a plurality of sample values, each of the sample values indicative of a respective location of a mobile tag and based on at least one signal communicated with the tag; associating each of the sample values with a respective one of a plurality of filter parameter values, the one filter parameter value indicative of a confidence in the associated sample value; filtering the sample values thereby providing an estimate indicative of a current location of the tag, wherein the filtering step comprises the step of combining the sample values via a weighted filtering algorithm based on the associated filter parameter values; storing the estimate in memory; determining a value indicative of a number of lost antenna paths for the tag; and determining whether the tag is in a dead zone based on the value indicative of the number of lost antenna paths. - View Dependent Claims (26, 27)
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Specification