Delay Compensation for Distributed MIMO Radar with Non-Orthogonal Waveforms

Distributed multi-input multi-output (MIMO) radar with non-orthogonal waveforms has become a critical problem because waveform orthogonality may be lost as waveforms experience distinct delays and Doppler across different transmit-receive propagation paths. In such cases, the widely used matched filter (MF) cannot perfectly separate the waveforms, and it outputs the filtered echo of the desired waveform (auto term) as well as multiple undesired waveform residuals (cross terms). In this paper, a transmit delay compensation scheme is proposed by employing a set of transmit delay compensation variables to control the cross terms so that they can be utilized to enhance target detection. Specifically, the probability of detection is maximized by optimizing the delay parameters. To solve the resulting nonconvex problem, an optimum solution based on multi-dimensional search and a computationally efficient suboptimal method are proposed. Simulation results show that the proposed delay compensation approach can substantially improve the target detection performance.