  In this letter, a novel nested PARAFAC algorithm was proposed to improve the
8D parameters estimation performance for the bistatic EMVS-MIMO radar. Firstly,
the outer part PARAFAC algorithm was carried out to estimate the receive
spatial response matrix and its first way factor matrix. For the estimated
first way factor matrix, a theory is given to rearrange its data into an new
matrix, which is the mode-1 unfolding matrix of a three-way tensor. Then, the
inner part PARAFAC algorithm was used to estimate the transmit steering vector
matrix, the transmit spatial response matrix and the receive steering vector
matrix. Thus, the transmit 4D parameters and receive 4D parameters can be
accurately located via the abovementioned process. Compared with the original
PARAFAC algorithm, the proposed nested PARAFAC algorithm can avoid additional
reconstruction process when estimating the transmit/receive spatial response
matrix. Moreover, the proposed algorithm can offer a highly-accurate 8D
parameters estimaiton than that of the original PARAFAC algorithm. Simulated
results verify the effectiveness of the proposed algorithm.
