A method of direction of arrival (DOA) and direction of departure (DOD) angle estimation based on polynomial rooting for bistatic multiple-input multiple-output (MIMO) radar with uniform circular array (UCA) configuration is proposed in this paper. The steering vector of the UCA is firstly transformed into a steering vector with a Vandermonde structure by using the Jacobi-Anger expansion. Then the null-spectrum function of the MIMO radar can be written as an expression in which the transmit and receive steering vectors are decoupled. Finally, a two-step polynomial rooting is used to estimate DOA and DOD of targets instead of two-dimensional multiple signal classification (MUSIC) search method for bistatic UCA MIMO radar. The angle estimation performance of the proposed method is similar to that of the MUSIC spectral search method, but the computation burden of the proposed polynomial rooting algorithm is much lower than that of the conventional MUSIC method. The simulation results of the proposed algorithm are presented and the performances are investigated and analyzed.

Research on multiple-input multiple-output (MIMO) radar has been growing as evidenced by an increasing body of literature [

Unfortunately, both the ESPRIT and the polynomial rooting method are designed for ULAs. The steering vector of the ULA is dependent on

In order to come up with computationally efficient high-resolution DOA estimators for UCAs, the so-called beamspace transform [

In this paper, direction finding for bistatic MIMO radar with UCA configuration employing polynomial rooting is presented. Transmit and receive steering vectors are firstly decomposed using the Jacobi-Anger expansion [

The remainder of this paper is organized as follows. In Section

Consider a narrowband bistatic MIMO radar system with

Cosider that

The array covariance matrix can be written as

The signals and the noises are assumed to be stationary, uncorrelated random processes; substituting

In practical situations, the exact array covariance matrix

The eigenvalue decomposition of

The MUSIC null-spectrum function is defined as [

The transmit and receive steering vectors of the UCAs can be denoted as [

By using the Jacobi-Anger expansion, we can mathematically express the

The receive steering vector can be treated in the same way as the transmit steering vector; therefore, we obtain

Using the notations

By substituting the obtained roots

Here, we present simulation results showing the statistical performance of the proposed algorithm when using UCA configuration. Consider a narrowband bistatic MIMO radar system with 4 transmit antennas and 3 receive antennas; both are UCAs with radius equal to

The angle estimation result of two targets.

With the same configuration of the simulation as before, Figure

RMSE in DOA and DOD estimation versus SNR.

DOA

DOD

Finally, we compare angle estimation performance of MUSIC spectrum with the searching step 0.01° and polynomial rooting method with

Angle estimation RMSE versus SNR.

The first target

The second target

In this paper, we have proposed a new technique to transform the steering vector of the UCA configuration into a steering vector with a Vandermonde structure in bistatic MIMO radar by using the Jacobi-Anger expansion. The two-step polynomial root finding algorithm has then been used to estimate DOA and DOD of the targets. The simulation results show that the proposed algorithm provides good performances in angle estimation. In addition, the proposed polynomial rooting angle estimation method avoids spectral search and reduces the computational complexity for bistatic MIMO radar with UCA configure.

This work was supported in part by the National Natural Science Foundation of China (61372136, 61172137, and 61271290) and in part by the Fundamental Research Funds for the Central Universities (K5051202005, and K5051302089).