Patent ID: 7617036

Claim:
A method for determining a velocity of a vehicle comprising: calculating an initial estimation of the velocity of the vehicle based on rates of rotation of a plurality of wheels on the vehicle, wherein the rates of rotation of the plurality of wheels are detected by wheel speed sensors and the acceleration of the vehicle is at least partially determined by an accelerometer; modifying the initial estimation based on an acceleration of the vehicle to generate a modified estimation of the velocity of the vehicle if any of the wheels on the vehicle are in a brake control situation, wherein said modification of the initial estimation comprises: calculating a rotational acceleration for each wheel on the vehicle; comparing the acceleration of the vehicle to the rotational acceleration for each wheel on the vehicle, said comparison being indicative of a coefficient of friction between each of the wheels on the vehicle and a driving surface on which the vehicle is traveling; and limiting the gradient of the initial estimation based on the acceleration of the vehicle and said comparison of the detected acceleration of the vehicle and the rotational acceleration for each wheel; and continuously repeating said calculation of the initial estimation and said modification of the initial estimation.