The Low Altitude Moving Target Detection Technology Based On Mimo Radar Research

Tracking targets in a low-grazing angle scenario is one of the most challenging problems in radar, and the most difficult problem is multipath suppression. Multipath makes the received echo fluctuate, and the detection performance decline rapidly.Aiming at the problem of low-altitude target detection, MIMO radar technology can provide both frequency diversity and spatial diversity, and can reduce the probability of multipath cancellation, so MIMO radar can detect and track the target more effectively and reliably, and is studied widely to solve the problem in low-altitude target detection.This dissertation focuses on the problem of multipath suppression and target detection. Target detection method in multipath is studied, which is based on orthogonal frequency division multiplexing-multiple input multiple output (OFDM-MIMO) radar configuration and time reversal-multiple input multiple output (TR-MIMO) radar configuration. The main work is listed as follows:1. The impact of radar detection performance due to the multipath is analyzed, including the echo amplitude and the echo power. MIMO radar configuration and its detection performance is discussed, and compared with the traditional phased array radar.2. Aiming at the problem that the traditional multipath suppression technique can not effectively and reliably detect and track target, a method based on the generalized likelihood ratio test (GLRT) of OFDM-MIMO radar multipath suppression is proposed. This method uses both frequency diversity and spatial diversity technologies, which can reduce the probability of multipath cancellation effectively. The improvement of performance under OFDM-MIMO radar configuration is verified by the numerical results.3. Combining the MIMO radar technology and the time reversal technology, the signal-to-noise ratio is improved by tuning the transmitted waveforms to the propagation medium and the target scattering characteristics. The benefits of the proposed TR-MIMO detection includes:(1) exploiting the spatial diversity;(2) using time reversal to adaptively adjust the radar waveforms to the scattering characteristics of the channel;and it is demonstrated that a MIMO radar combined with time reversal (TR-MIMO) improves target detectability compared with statistical MIMO (S-MIMO).