On Estimating the Angle of Arrival and Doppler Frequency in Bistatic and Multistatic Systems

We consider a bistatic and a multistatic sensing scenario, in which both the sensing transmitter and receiver(s) are equipped with multiple antennas. Assuming perfect synchronization among the transmitter and receiver(s), we address the problem of estimating the Doppler frequency and the angle of arrival of a passive object. The input to this estimation problem is the received noisy sensing signals at multiple time instance(s), while the output is the estimated angle of arrival and Doppler frequency either at individual sensing nodes or at a hypothetical centralized entity. In this rather general setting, we evaluate how the estimation performance is affected by the system parameters such as the number of receive access points and the available time samples. Our numerical results show that the Cramér-Rao lower bound of the estimated parameters inversely depends on the number of time samples of the received echoes. We also observe an even stronger inverse dependency on the number and locations of the receiver access points within the region of interest, indicating the advantages of adopting a distributed multiple-input multiple-output architecture for sensing purposes.