Abstract:

Aiming at the problem of counter reconnaissance for multiple input and multiple output (MIMO) radar, the signal model of joint direction and frequency estimation based on the technique of passive synthetic arrays is constructed. The direction and frequency unambiguous estimation is achieved by the spatial spectrum algorithm based on the synthetic arrays at different velocities. Furthermore, the CramerRao bound (CRB) of joint estimation for multi radiation sources is derived under unknown frequency and the CRB of direction estimation for single array radar is derived under known frequency. Moreover, the closedform solutions of CRB for direction estimation to MIMO radar and phased array radar are respectively derived, and the estimation performance of two types is analyzed and compared. The theoretical analysis and simulation results illustrate that the proposed algorithm can reach direction and frequency unambiguous estimation for MIMO radar and the estimation performance can achieve asymptotically CRB with the signaltonoise and the number of synthetic arrays increasing in the presence of frequency unknown; The ratio of direction estimation performance between MIMO radar and phased array radar is only related with transmit beamforming gains of phased array radar and the array number in the presence of frequency known. Lastly, simulation results verify the correctness of the theoretical analysis and the effect of the proposed algorithm.