临近空间平台高分辨率宽测绘带重复访问合成孔径雷达成像模式及算法研究

High Resolution Wide Swath Repeat Acquisition SAR Imaging Mode and Algorithm with Near Space Platform

  • 摘要: 本文提出一种临近空间高分辨率宽测绘带快速重复访问模式。发射天线采用线性相控阵列天线,结合合适的接收天线模式,共形成一个主瓣两个栅瓣,对同一成像区域快速重复访问。在方位向高分辨率及距离向宽测绘带的要求下,各子波束方位向回波在方位时域及频域均存在混叠。本文提出一种多通道多子波束重建算法,以对方位向各子波束回波进行分离。采用非线性调频尺度算法对分离后各子波束回波进行成像。并对各子图像的成像性能参数进行研究。本文给出了一个系统设计示例。实验仿真结果表明,本文提出的成像模式及所提出的信号处理流程正确有效。计算所得性能参数表明,各子图像质量可满足实际应用的要求。

     

    Abstract: In this paper a short term repeat acquisition high resolution wide swath imaging mode with near space platform is proposed. The emission antenna is designed as linear phase steered array. It combined with proper receiving antenna mode forms one main lobe and two grating lobes, which provides the short term repeated visiting to the same imaged area. In order to get high azimuth resolution and wide swath, the echoes of the all sub beams are superimposed both in azimuth time and Doppler frequency domain. The paper proposes a multiple-channel multiple-beam reconstruction algorithm to separate them. The nonlinear chirp scaling algorithm is used to form the images of the sub beams. The performance parameters are analyzed as well. An example system design is given in this paper. The simulation results verify the validity and the correctness of the proposed imaging mode and the processing method. The calculated performance parameters show the qualities of the sub images satisfy the request of the applications.

     

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