Ground moving target imaging method study using GNSS-based passive bistatic radar
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摘要: 基于全球卫星导航系统(GNSS)的无源双基地雷达是一种极具潜力的天基雷达系统,具有功耗低、隐蔽性好等优点. 但由于信号功率密度低,需要通过长时间积累提升目标信噪比(SNR),而目标运动会造成距离徙动和多普勒扩散,传统的脉冲多普勒雷达处理方法不再适用. 针对此问题,本文提出一种基于拉东傅里叶变换的动目标成像方法. 首先通过在传统拉东傅里叶变换中增加去多普勒调频率补偿因子,联合搜索并估计动目标的三维参数,然后通过参数补偿实现目标在距离多普勒域的聚焦成像. 该方法既考虑了多普勒相位调制的影响,又在距离频域快速部署实现,可以达到比传统方法更好的聚焦效果. 最后基于GPS卫星照射源的实测实验对所提方法的性能进行了验证.
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关键词:
- 全球卫星导航系统(GNSS) /
- 无源双基地雷达 /
- 动目标成像 /
- 拉东傅里叶变换 /
- 长时间相干积累
Abstract: Passive bistatic radar based on Global Navigation Satellite System (GNSS) is a potential space-based radar system, which has the advantages of low power consumption and good concealment. Due to the low signal power density, it is necessary to increase the target signal-to-noise ratio through long-time integration. However, target motion will cause range migration and Doppler spread, and the traditional pulse doppler radar processing method is no longer applicable. Aiming at this problem, this paper proposes a moving target imaging method based on Radon Fourier transform (RFT). Firstly, by adding the Doppler rate compensation factor to the traditional RFT method, the three-dimensional parameters of the moving target are jointly searched and estimated. And then through parameters compensation to complete the target imaging in the range Doppler domain. This method not only considers the influence of Doppler phase modulation, but also realizes rapid deployment in the range frequency domain, which can achieve a better imaging effect than traditional methods. The performance of the proposed method is verified based on the actual experiment using GPS satellite as the illuminator of opportunity. -
表 1 实测实验参数设置
参数 取值 参数 取值 信号源 GPS L5 卫星 PRN 1 载频 1 176.45 MHz 等效PRF 1 000 Hz 系统采样率 62 MHz 信号带宽 10.23 MHz 天线增益 10 dBi 积累时长 4 s -
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