Estimating the ego-motion of a vehicle, e.g., the self-motion of the vehicle, can be improved by pre-processing data from two or more radars onboard the vehicle using a processor common to the two or more radars. The common processor can pre-process the data using a velocity vector processing technique that can estimate a velocity vector at each point of a predefined number of points, such as arranged in a grid in the field-of-view of radars, with coordinates (X, Y, Z (optional)), where U is the component of the velocity in the X-direction, V is the component of the velocity in the Y-direction, and W is the component of the velocity in the optional Z-direction.