Patent ID: 7474214
Filing Date: 2009-01-06
Classification: B60C

Abstract:
1. A method for determining the position of four tires on corresponding four wheels in a vehicle, each wheel having an axis of rotation, each tire having an embedded Radio Frequency IDentification (RFID) tag, wherein the RFID tags embedded in the four tires have respective identifiers denoted as ID 1 , ID 2 , ID 3 , and ID 4 , wherein the four wheels are a front left wheel (wheel 1 ), a front right wheel (wheel 2 ), a rear left wheel (wheel 3 ), and a rear right wheel (wheel 4 ), wherein L denotes a distance between wheel 1 and wheel 3 and is equal to a distance between wheel 2 and wheel 4 , wherein l denotes a distance between wheel 1 and wheel 2 and is equal to a distance between wheel 3 and wheel 4 , wherein the axis of the four wheels have (X, Y) coordinates with respect to X and Y axes of a rectangular X-Y coordinate system, wherein the X and Y axes form a plane comprising the axes of the four wheels, wherein the (X, Y) coordinates on the axis of the four wheel are (−l/2, L/2) for wheel 1 , (l/2, L/2) for wheel 2 , (−l/2, −L/2) for wheel 3 , and (l/2, −L/2) for wheel 4 , and wherein the method comprises: determining a position P(x, y) to place a reader antenna subject to x<0 and y>0, wherein (x, y) denotes the (X, Y) coordinates of position P in the X-Y coordinate system, wherein d placing the reader antenna at the determined position P(x, y); after said placing and for z=1, 2, 3, and 4, said RFID reader emitting N signals (N at least 2) to the RFID tag whose identifier is IDz and measuring a delay Tzn for receiving the signal n (n=l, 2, . . . , N) reflected from the RFID tag whose identifier is IDz and determining Tz as a minimum of Tzn (n=l, 2, . . . , N), resulting in Ta<Tb<Tc<Td such that a, b, c, and d are each 1, 2, 3, or 4 and differ from one another; identifying the tire having identifier IDa, IDb, IDc, and IDd as being on wheel