Patent ID: 7647177
Filing Date: 2010-01-12
Classification: G01S

Abstract:
1. A method for determining the position of a vehicle, the method comprising: transmitting a first transmission signal from a transmitter at a vehicle toward three or more beacons associated with a work area; determining a first aggregate elapsed time between the transmission of the first transmission signal to a first beacon and a return signal from the first beacon to the vehicle with compensation for a bias delay associated with the transmitter and compensation for a first bias delay associated with the first beacon; converting the first aggregate elapsed time into a first position curve in at least two spatial dimensions for vehicle; determining a second aggregate elapsed time between the transmission of the first transmission signal to a second beacon and a return signal from the second beacon to the vehicle with compensation for the bias delay associated with the transmitter and compensation for a second bias delay associated with the second beacon; converting the second aggregate elapsed time into a second position curve in at least two spatial dimensions for vehicle; determining a third aggregate elapsed time between the transmission of the first transmission signal to a third beacon and a return signal from the third beacon to the vehicle with compensation for the bias delay associated with the transmitter and compensation for a third bias delay associated with the third beacon; converting the third aggregate elapsed time into a third position curve in at least two spatial dimensions for vehicle; and estimating a position of the vehicle at a confluence or intersection of the first position curve, the second position curve, and the third position curve.