Joint Angle and Range Estimation in the Fda-Mimo Radar: The Reduced-Dimension Root Music Algorithm

The frequency diverse array (FDA) multiple-input multiple-output (MIMO) radar is capable of producing the angle-range-dependent beampattern by utilizing a small frequency increment across the transmit elements, which enables to jointly calculate the angle and range estimates of the targets. However, the methods with tremendous computational burden, e.g., two-dimensional (2D) spectrum peak search (SPS), are involved due to the coupling of parameters, i.e., angle and range. In this study, We propose a reduced-dimension root MUSIC (RD-root-MUSIC) algorithm to detect the angle and range of targets in the FDA-MIMO radar. Specifically, we firstly decompose the angle and range by reconstructing the 2D-MUSIC spatial spectrum, where, resultantly, the range component is dismissed and the angle-dependent spatial spectrum function can be achieved. Moreover, to circumvent the SPS, the polynomial root finding is employed to obtain the angle estimates. Furthermore, we derive the closed-form solution to the range estimates which can be directly calculated based on the angle estimates. The proposed algorithm remarkably reduces the computational complexity without estimation performance degradation. In addition, the Cramér-Rao bounds (CRBs) are presented and the simulation results are provided to demonstrated the effectiveness of the proposed algorithm.