Enhanced Parameters Estimation With STAP-Based PA-FDA Dual-Mode Radar

Space-time adaptive processing (STAP) is significant for detecting moving targets with phased array (PA) and frequency diverse array (FDA). However, the parameter estimation will be affected by the residual clutter. To mitigate this issue, this article puts forward an enhanced moving target parameter estimation method for STAP-based PA-FDA dual-mode radar, where dual-mode radar contains several advantages: it has simultaneously narrow-beam tracking and wide-beam searching capabilities and it can resolve range ambiguity problem with FDA mode and improve target detection performance with PA mode. With the dual-mode cooperative design, an accurate clutter covariance matrix is reconstructed to calculate weights for the maximum likelihood (ML) parameters estimator, where range-ambiguous clutter is considered. The Taylor series expansion of the ML estimator is developed to mitigate the problem of biased parameter estimation caused by residual clutter after suppression. Moreover, enhanced unambiguous range estimation is proposed with PA-FDA. Overall, the proposed method with PA-FDA enhances the parameters estimation performance of moving target. Simulation experiments are employed to demonstrate the validity of the proposed approach.