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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2021, Vol. 42 ›› Issue (6): 324502-324502.doi: 10.7527/S1000-6893.2020.24502

• Electronics and Electrical Engineering and Control • Previous Articles     Next Articles

Error model-aided autofocus for airborne high resolution wide swath DBF-SAR

BAO Yue1, CHEN Junyu1, SHI Tianyue1, MAO Xinhua1,2   

  1. 1. College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2. Key Laboratory of Radar Imaging and Microwave Photonics, Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2020-07-06 Revised:2020-07-20 Online:2021-06-15 Published:1900-01-01
  • Supported by:
    National Natural Science Foundation of China(62071225,61671240);Natural Science Foundation of Jiangsu Province(BK20170091);National Defense Science and Technology Key Laboratory Fund(6142503180201)

Abstract: The High-Resolution Wide-Swath (HRWS) Digital Beam Forming (DBF) Synthetic Aperture Radar (SAR) operates with multi-channel spatial sampling instead of partial time-domain sampling, effectively easing the contradiction between high resolution and wide swath of SAR images, exhibiting important military and civilian values. Conventional DBF-SAR imaging methods assume that the relative position of the radar sensor is accurately known. However, phase errors caused by inaccurate sensor positions will seriously affect the high-resolution imaging capability of the DBF-SAR. Based on the Polar Format Algorithm (PFA), the analytical model of the residual azimuth phase error after DBF-SAR imaging processing is derived, and the effect of the error on the imaging quality is analyzed. An autofocusing algorithm based on image contrast optimization is proposed with the deduced analytical structure model of a priori phase errors. This method reduces the spatial dimension of the parameters to be estimated, improving the parameter estimation accuracy and calculation efficiency of the autofocus algorithm by introducing a priori analytical structure information. Simulation data processing results verify the correctness of theoretical analysis and the effectiveness of the proposed method.

Key words: Synthetic Aperture Radar (SAR), High-Resolution Wide-Swath (HRWS), Polar Format Algorithm (PFA), autofocus, Contrast Optimization Autofocusing Algorithm (COAA)

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