Passive Positioning and Movement Direction Method Based on Doppler Shift Change

The paper proposes a method for determining the location and direction of an object (hereinafter referred to as the OwlEars-1 method) based on changes in the Doppler shift of the signal emitted by this object. To determine the location, three short measurements are taken over one signal period to determine the relative change in the Doppler shift between these three measurements. There are several prerequisites for obtaining correct results. It is assumed that the object’s speed is known with a specific error, and the trajectory of movement is linear over the interval of three consecutive measurements. The absence or incomplete fulfillment of these prerequisites affects the method’s accuracy. The key advantages of the method are the use of the Doppler shift change as an input signal and the absence of the need for high-precision synchronization of receivers. The input data for the method is in the form of a change in the Doppler shift, instead of a signal without a Doppler shift, which allows the method to be applied to ambiguous signals. Low requirements for receiver synchronization simplify the implementation of the method, since only the change in the Doppler shift is used, unlike the phase method, where the TDoA (time difference of arrival) phase shift is the main parameter. The proposed mathematical model of the method has been validated by a series of simulations, particularly for a moving object emitting an acoustic signal. Further research steps are defined to investigate the method’s accuracy for various deviations from the assumptions made in the method.