Robust Waveform Optimization for MIMO-OFDM-Based STAP in the Presence of Environmental Uncertainty

Abstract

The issue of robust orthogonal frequency division multiplexing (OFDM) multi-input multi-output (MIMO) radar waveform optimization is considered here with clutter uncertainty to enhance the worst-case detection probability of the MIMO-OFDM radar-based space–time adaptive processing (STAP). Robust optimization is necessary on account of the fact that waveform design is generally sensitive to the initial parameter estimation errors. According to the max–min approach, the issue of robust waveform design is constructed with the criterion of maximizing the worst-case output SINR, namely signal-to-interference-noise ratio, under the constraints of the clutter covariance matrix (CCM) errors and constant modulus to ease this sensitivity systematically, and hence the robustness of STAP’s detection to the uncertainty in the CCM estimate can be enhanced. To handle the acquired nonlinear and sophisticated issue, an iterative approach based on diagonal loading (DL) is presented, in which the inner and outer optimization issues can be recast into semidefinite programming ones by employing DL method, and thus both of them can be tackled in an efficient way. As compared to uncorrelated waveforms and the non-robust algorithm, numerical simulations reveal that the developed approach can enhance the robustness of STAP’s detection to the uncertainty in the CCM considerably.