Abstract

Frequency diverse array (FDA)-aided spacetime adaptive processing (STAP) is a useful approach to suppressing range-ambiguous clutter in airborne radars. In general, FDA-STAP schemes based on subspace techniques can provide excellent clutter rejection capability when only limited secondary data are available. However, transmit array gain and phase errors may cause serious performance degradation. To overcome this problem, a robust subspace-based FDA-STAP algorithm is proposed in this work: RSUB-FDA-STAP. Firstly, the influence of transmit array errors on subspace-based FDA-STAP is analyzed, indicating that the errors must be calibrated. Secondly, an error calibration vector is constructed, and an optimization problem is formulated to estimate the errors. Finally, by minimizing the objective function of the optimization problem, the errors are effectively estimated with limited secondary data, and an effective RSUB-FDA-STAP is developed for range-ambiguous clutter suppression. The proposed method effectively suppresses range-ambiguous clutter under transmit array gain and phase errors in comparison with existing robust FDA-STAP techniques. Numerical simulations demonstrate that the developed RSUB-FDA-STAP shows superior robustness against transmit array gain and phase errors.

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