Some phase synchronization algorithms for coherent MIMO radar

Practical realization of the coherent processing in widely separated multiple-input multiple-output (MIMO) radar systems requires the development of implementable techniques to ensure a common notion of phase among all the distributed radar elements. In this work, we present two effective approaches to achieve phase synchronization in coherent MIMO radar systems. The first one is the master-slave closed-loop approach, which employs a master-slave architecture. This method is very simple, and is particularly suitable for fine phase synchronization. The second one is the round-trip algorithm, which employs an unmodulated beacon signal to travel through all the radar elements in a round-trip manner. These algorithms are both time asynchronous in nature, and they require no a priori establishment of either time or frequency synchronization. Under a similar analytical framework, we mathematically characterize each of these algorithms, and further derive and analyze the statistical properties of the corresponding phase synchronization error.