MIMO-SAR Imaging Based On Double Frequency Slope Waveform

As a new radar technology, MIMO(Multi-Input Multi-Output) radar has been widely concerned by domestic and foreign researchers. Because of its comprehensive utilization of array and diversity technology, much more equivalent observation channel and signal processing DOF than traditional synthetic aperture radar(SAR) were obtained, which can effectively resolve the contradictions between the high-resolution and wide swath imaging in the SAR. However, Traditional radar imaging algorithms cannot be directly used in the MIMO due to the characteristics of multiple input and multiple output arrays. Simultaneously MIMO-SAR imaging will be affected by the mutual interference between each transmitted waveforms, the equivalent phase center error and array distributed.Aiming at these problems, the optimization design of waveform, the compensation of equivalent phase center error and MIMO radar array configuration were in-depth studied in this thesis from the principle of MIMO-SAR. In addition, a new imaging algorithm was proposed base on the characteristics of the waveform. Our research work can be described as following.1. Considering the orthogonal performance and Doppler tolerance of the MIMO transiting waveform, a double frequency waveform(DFS) was proposed and the correlation properties and Doppler tolerance of DFS were focuses on researching. In order to improve the performance of pulse compression, window of the waveform were designed.2. Through analyzing of equivalent phase center error influence on MIMO radar imaging, the error model of equivalent phase center is constructed, and the corresponding compensation method is given. Meanwhile, according to the designed rule for uniform equivalent spatial samplings, the MIMO-SAR transceiver array is optimized configuration.3. Aiming at the model of DFS, the MIMO-SAR echo waveform was model. The range-Doppler domain’s feature of the echo was analyzed, then the compression function of distance and phase compensation function and the phase compensation in the range-Doppler domain is given. Through compared with the imaging performance of OFDM- LFM, highlight the advantages of the DFS waveform in MIMO-SAR.4. Aiming at the far distance, wide swath and high-resolution of range migration problem, a frequency domain correction range imaging method was proposed. In addition, through real wide swath imaging, the effectiveness of MIMO-SAR to resolve the contradictions between the high-resolution and wide swath imaging was verified.