Patent Document ID: 9414239
Application ID: 13523659
Patent Flag: 1

Claim One:
1. A method for determining location and timing for wi-fi nodes in a wi-fi network, wherein at least one of the nodes is moving, and the nodes have free running clocks, with a corresponding clock error parameter, the method comprising: obtaining observations of count stamps from the free running clocks for wi-fi packet transmissions between nodes in a group of the nodes occurring over a current time interval, the nodes in the group having a radio, and a processor for obtaining a count stamp from the free running clock in the node, the count stamp corresponding to receipt of a wi-fi packet transmission from another node in the group; with a programmed processor, generating from the model an estimate of network state based on the observations and a previous estimate of the network state, the network state comprising: a first difference between a previous clock parameter in a previous time interval and a corresponding clock parameter in the current time interval; a second difference between location parameter estimates in the previous time interval and corresponding location parameters in the current time interval; the model of network state characterizing statistical properties of errors between clock and location parameter estimates for a previous time interval and corresponding clock and location parameters in the current time interval; with a programmed processor, adding the estimate of network state to clock parameter and location parameter estimates of a previous time interval to recursively calculate updated clock parameter and location parameter estimates for the current time interval; and providing a solution of node position from the location parameter estimates for the current time interval via wireless transmission to at least one of the nodes.