Existence and uniqueness of motion parameters in active ranging

Motion estimation of distributed objects is discussed. Measurements include position plus Doppler. We show that 2D position plus Doppler is sufficient to uniquely determine the motion parameters of an object on a circular trajectory except for special cases. The uniqueness enhances occlusion tolerance and implies an approach to associating features. We show that the sensitivity of calculated motion parameters to measurement error is bounded. We also show that the error in the motion parameters tends to zero as the measurement error approaches zero