METHOD FOR DETERMINATION OF WIRELESS TERMINALS POSITIONS AND ASSOCIATED SYSTEM AND APPARATUS THEREOF
First Claim
1. A position estimation method to estimate the position of wireless communications nodes using parameters of the wireless transmissions, said method comprising:
- a signal strength collection step where parameters of wireless transmission are collected from wireless communications nodes;
a virtual anchor selection step where for each target node whose position is to be estimated, one or more wireless communications nodes are selected to be virtual anchors based on some criteria; and
a position estimation step where position of the target node is estimated using the parameters of wireless transmissions associated with the selected virtual anchors and the target node;
wherein a position refinement iteration where the virtual anchor selection step and the position estimation step are re-iterated until there is no significant change in estimated positions.
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Abstract
Conventional position estimation methods require the deployment of more fixed anchors in order to increase the accuracy in a crowded indoor environment, or they suffer from inaccuracies due to multipath fading. The present invention overcomes the problems associated with the prior arts by selecting one or more mobile nodes as virtual anchors when estimating the position of a target mobile node. This takes advantage of the fact that mobile nodes are closer to the target mobile node than the access points in most typical deployments, thus eliminating the need to deploy more access points or fixed anchors for the purpose of position determination. After obtaining an initial estimate of the position of the target mobile node, the target mobile node can serve as virtual anchors to estimate the positions of other mobile nodes, which can then be used to further refine the position estimate of the target mobile node.
174 Citations
16 Claims
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1. A position estimation method to estimate the position of wireless communications nodes using parameters of the wireless transmissions, said method comprising:
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a signal strength collection step where parameters of wireless transmission are collected from wireless communications nodes; a virtual anchor selection step where for each target node whose position is to be estimated, one or more wireless communications nodes are selected to be virtual anchors based on some criteria; and a position estimation step where position of the target node is estimated using the parameters of wireless transmissions associated with the selected virtual anchors and the target node; wherein a position refinement iteration where the virtual anchor selection step and the position estimation step are re-iterated until there is no significant change in estimated positions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A position estimation system for estimating a position of wireless communications node using parameters of the wireless transmissions, said system comprising:
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a plurality of wireless communications nodes; and a position estimating node with the arrangement such that the said position estimating node estimates the position of one or more wireless communications nodes wherein the position estimating node comprises; a parameter collection unit to collect parameters of wireless transmission from the wireless communications nodes; a virtual anchors selection unit to select one or more wireless communications nodes to be virtual anchors for the position estimation of a target communications node based on some criteria; and a position estimation unit to estimate the position of the target node using the parameters of wireless transmissions associated with the selected virtual anchors and the target node; and wherein the position estimating node iteratively selects virtual anchors and estimates the position of communications nodes until there is no significant change in estimated positions. - View Dependent Claims (15)
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16. A position estimating apparatus for estimating the position of wireless communications nodes using parameters of the wireless transmissions, said apparatus comprising:
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a signal strength collection unit to collect parameters of wireless transmission from wireless communications nodes; a virtual anchor selection unit to select one or more wireless communications nodes to be virtual anchors based on some criteria for each target node whose position is to be estimated; a position estimation unit to estimate position of the target node using the parameters of wireless transmissions associated with the selected virtual anchors and the target node; and a position refinement iteration unit which reiterates the virtual anchor selection and the position estimation until there is no significant change in estimated positions.
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Specification