Method for determination of wireless terminals positions and associated system and apparatus thereof

摘要

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.

主权项

1. A position estimation method to estimate positions of wireless communications nodes using parameters of wireless transmissions, said method comprising:
a signal strength collection step where signal strength parameters of wireless transmissions are collected from wireless communications nodes; a virtual anchor selection step where for a target node whose position is to be estimated, one or more wireless communications nodes are selected to be virtual anchors based on some criteria; a position estimation step where position of the target node is estimated using the signal strength parameters of wireless transmissions associated with the selected virtual anchors and the target node; and a position refinement iteration step where the virtual anchor selection step and the position estimation step are re-iterated until there is no significant change in estimated positions, and wherein the virtual anchor selection step selects a first communications node as a virtual anchor for the position estimation of a second communications node, such that said first communications node is a target node in a previous position refinement iteration.