通过对地震计数学模型的详细分析,阐明了不同形式的反馈网络在地震计中的不同作用。结果表明:① 机械部分对反馈式地震计频率特性的影响在一定条件下可以忽略 ② 地震计的类型和通频带由反馈网络决定 ③ 反馈扩大了地震计的动态范围,降...通过对地震计数学模型的详细分析,阐明了不同形式的反馈网络在地震计中的不同作用。结果表明:① 机械部分对反馈式地震计频率特性的影响在一定条件下可以忽略 ② 地震计的类型和通频带由反馈网络决定 ③ 反馈扩大了地震计的动态范围,降低了地震计的分辨率 ④ 反馈系统对地震计的信噪比没有影响。展开更多
Based on dual-frequencies dual-apertures spaceborne SAR （Synthetic Aperture Radar）, a new SAR system with four receiving channels and two operation modes is presented in this paper, SAR imaging and Moving Target Ind...Based on dual-frequencies dual-apertures spaceborne SAR （Synthetic Aperture Radar）, a new SAR system with four receiving channels and two operation modes is presented in this paper, SAR imaging and Moving Target Indication （MTI） are studied in this system. High resolution imaging with wide swath is implemented by the Mode Ⅰ, and MTI is completed by the Mode Ⅱ. High azimuth resolution is achieved by the Displaced Phase Center （DPC） multibeam technique. And the Coherent Accumulation （CA） method, which combines dual channels data of different carrier frequency, is used to enhance the range resolution. For the data of different carrier frequency, the two aperture interferometric processing is executed to implement clutter cancellation, respectively. And the couple of clutter suppressed data are employed to implement Dual Carrier Frequency Conjugate Processing （DCFCP）, then both slow and fast moving targets detection can be completed, followed by moving target imaging. The simulation results show the validity of the signal processing method of this new SAR system.展开更多
基金Supported by the National Natural Science Foundation of China (NSFC) (No.60772103)China National Key Laboratory of Microwave Imaging Technology Foundation (No.9140C1903050804)
文摘Based on dual-frequencies dual-apertures spaceborne SAR （Synthetic Aperture Radar）, a new SAR system with four receiving channels and two operation modes is presented in this paper, SAR imaging and Moving Target Indication （MTI） are studied in this system. High resolution imaging with wide swath is implemented by the Mode Ⅰ, and MTI is completed by the Mode Ⅱ. High azimuth resolution is achieved by the Displaced Phase Center （DPC） multibeam technique. And the Coherent Accumulation （CA） method, which combines dual channels data of different carrier frequency, is used to enhance the range resolution. For the data of different carrier frequency, the two aperture interferometric processing is executed to implement clutter cancellation, respectively. And the couple of clutter suppressed data are employed to implement Dual Carrier Frequency Conjugate Processing （DCFCP）, then both slow and fast moving targets detection can be completed, followed by moving target imaging. The simulation results show the validity of the signal processing method of this new SAR system.
