With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With ...With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.展开更多
FMCW-SAR因其体积小、重量轻、成本低和高分辨率等优点近年来发展迅速,在低成本的民事应用领域具有广阔的发展前景。传统脉冲SAR的系统冲击响应函数不同于FMCW-SAR,因而,脉冲SAR的快速回波模拟算法不能直接应用于FMCW-SAR。该文在分析...FMCW-SAR因其体积小、重量轻、成本低和高分辨率等优点近年来发展迅速,在低成本的民事应用领域具有广阔的发展前景。传统脉冲SAR的系统冲击响应函数不同于FMCW-SAR,因而,脉冲SAR的快速回波模拟算法不能直接应用于FMCW-SAR。该文在分析了条带FMCW-SAR信号特性的基础上,提出了其原始回波数据的2维频域快速模拟算法。该算法利用FFT快速实现了回波数据时域模拟方法中的距离向和方位向积分运算。与时域模拟方法相比,其计算效率提高了O(N a N r/log 2(N a N r))个数量级。点目标回波数据的仿真实验验证了所提算法的合理性和有效性。展开更多
基金supported by the National Basic Research Program of China(2011CB707001)the Fundamental Research Funds for the Central Universities(106112015CDJXY500001CDJZR165505)
文摘With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.
文摘FMCW-SAR因其体积小、重量轻、成本低和高分辨率等优点近年来发展迅速,在低成本的民事应用领域具有广阔的发展前景。传统脉冲SAR的系统冲击响应函数不同于FMCW-SAR,因而,脉冲SAR的快速回波模拟算法不能直接应用于FMCW-SAR。该文在分析了条带FMCW-SAR信号特性的基础上,提出了其原始回波数据的2维频域快速模拟算法。该算法利用FFT快速实现了回波数据时域模拟方法中的距离向和方位向积分运算。与时域模拟方法相比,其计算效率提高了O(N a N r/log 2(N a N r))个数量级。点目标回波数据的仿真实验验证了所提算法的合理性和有效性。
