Patent ID: 6885969

Claim:
A method for locating a mobile node in a partially synchronized wireless network, comprising: measuring a first time interval to transmit a first message from a first stationary node at a first known location to a mobile node at an unknown location; measuring a second time interval to transmit a second message from a second stationary node at a second known location to the mobile node, in which the first stationary node is time synchronized with the second stationary node; broadcasting, from the mobile node, a third message to a third stationary node at third known location and a fourth stationary node at fourth known location: measuring a first received signal strength of the third message at the third stationary node; measuring a second received signal strength of the third message at the fourth stationary node; determining a first set of possible coordinates of the mobile node from the first time interval and the second time interval; determining a second set of possible coordinates of the mobile node from the first received signal strength; determining a third set of possible coordinates of the mobile node from the second received signal strength; and intersecting the first, second and third sets of possible coordinates of the mobile node to estimate a location of the mobile node.