An Analysis of Phase Synchronization Mismatch Sensitivity for Coherent MIMO Radar Systems

摘要

In this study, the hybrid Cramer-Rao bound (CRB) is developed for targetlocalization, to establish the sensitivity of the estimation mean-square error(MSE) to the level of phase synchronization mismatch in coherent Multiple-InputMultiple-Output (MIMO) radar systems with widely distributed antennas. Thelower bound on the MSE is derived for the joint estimation of the vector ofunknown parameters, consisting of the target location and the mismatch of theallegedly known system parameters, i.e., phase offsets at the radars.Synchronization errors are modeled as being random and Gaussian. A closed-formexpression for the hybrid CRB is derived for the case of orthogonalwaveforms.The bound on the target localization MSE is expressed as the sum oftwo terms - the first represents the CRB with no phase mismatch, and the secondcaptures the mismatch effect. The latter is shown to depend on the phase errorvariance, the number of mismatched transmitting and receiving sensors and thesystem geometry. For a given phase synchronization error variance, thisexpression offers the means to analyze the achievable localization accuracy.Alternatively, for a predetermined localization MSE target value, the derivedexpression may be used to determine the necessary phase synchronization levelin the distributed system.