Coherent targets DOA estimation with electromagnetic vector sensors in MIMO radar

In this paper, we develop a joint transmit and receive diversity smoothing technique to estimate two dimensional direction-of-arrival (2D-DOA) of coherent targets with electromagnetic vector sensor (EMVS) array elements in multiple input multiple output (MIMO) radar. The DOA estimates are obtained through the estimation of the six components of the EMVS based on subspace based rotational invariance algorithm. It is based on the cross product of the vectors signal´s electric-field and the associate magnetic-field, which directly computes the direction cosines of the three-dimensional Cartesian coordinates. The proposed method utilizes the waveform diversity benefit drawn from the coherent MIMO radar. Compared to receive-only spatial smoothing, this scheme has more number of covariance matrices for averaging which reduces the correlation among the coherent targets leading to better estimation results.