This paper presents an experimental demonstration with respect to a high-range-resolution imaging scheme for software-defined receiver-based passive GPS-based SAR, and a signal processing scheme for imaging is proposed correspondingly. In the proposed scheme, to reduce the computational complexity and high-memory requirement for receiver, GPS signals are down-converted to baseband for digitized collection at first. After performing range compression, the region of interest is selected based on the numbers of detected compressed pulses. Thereafter, the detected compressed pulses are up-sampled, modulated by a waveform with the frequency larger than bandwidth value and then spectrum-equalized for obtaining high-resolution range-compressed signals. The field results obtained from both land and ocean scenarios indicate that compared to the conventional signal processing scheme for imaging, indeed the proposed scheme can provide a significantly lower range ambiguity around the scene center; compared with the authors’ previous related work (Zheng et al. in Sensors, 2017. https://doi.org/10.3390/s17071496 ), the proposed scheme is obviously more computationally efficient.

中文翻译：

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使用波形调制距离压缩脉冲的软件定义的基于 GPS 的 SAR 成像的高分辨率：现场实验演示

本文针对基于软件定义接收机的无源 GPS SAR 高分辨率成像方案进行了实验论证，并相应地提出了一种成像信号处理方案。在所提出的方案中，为了降低接收机的计算复杂度和高内存要求，首先将GPS信号下变频到基带进行数字化采集。执行距离压缩后，根据检测到的压缩脉冲的数量选择感兴趣的区域。此后，对检测到的压缩脉冲进行上采样，用频率大于带宽值的波形进行调制，然后进行频谱均衡以获得高分辨率的距离压缩信号。从陆地和海洋场景中获得的现场结果表明，与传统的成像信号处理方案相比，所提出的方案确实可以提供显着更低的场景中心周围的距离模糊度；与作者之前的相关工作（Zheng et al. in Sensors, 2017. https://doi.org/10.3390/s17071496）相比，所提出的方案显然计算效率更高。