The exact radar cross-section （RCS） measurement is difficult when the scattering of targets is low. Ful polarimetric cali-bration is one technique that offers the potential for improving the accuracy of RCS measurem...The exact radar cross-section （RCS） measurement is difficult when the scattering of targets is low. Ful polarimetric cali-bration is one technique that offers the potential for improving the accuracy of RCS measurements. There are numerous polarimetric calibration algorithms. Some complex expressions in these algo-rithms cannot be easily used in an engineering practice. A radar polarimetric coefficients matrix （RPCM） with a simpler expression is presented for the monostatic radar polarization scattering matrix （PSM） measurement. Using a rhombic dihedral corner reflector and a metal ic sphere, the RPCM can be obtained by solving a set of equations, which can be used to find the true PSM for any target. An example for the PSM of a metal ic dish shows that the proposed method obviously improves the accuracy of cross-polarized RCS measurements.展开更多
We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere...We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere, the radar cross section(RCS)of different metallic spheres is given at terahertz frequencies. The investigation of the RCS of polished metallic spheres shows the normalized RCS is always same to the metals’ normal incidence reflectivity when the sphere becomes electrically large. The metals which have high reflectivity(such as Al, Cu, Ag and Au) show that the corresponding RCS of the spheres is almost πa2 in terahertz band. The sphere’s RCS of the transition metal such as Fe begins to decrease obviously since the far infrared.展开更多
This paper studies the development on the first order sea clutter cross section for bistatic high frequency surface wave radar (HFSWR). Based on the received first order electric field expression, a closed-form of cro...This paper studies the development on the first order sea clutter cross section for bistatic high frequency surface wave radar (HFSWR). Based on the received first order electric field expression, a closed-form of cross sections is derived to account for the case of receiving antenna array being mounted on the shipborne platform. The uniform linear motion and sway motion components are assumed to be responsible for the observed differences in comparison with the bistatic fixed antenna case. Correspondingly, simulations are conducted to study the sea clutter spectral characteristics for these two cases versus different system parameters and sea state conditions. It is shown numerically that the forward motion component will spread the Bragg lines severely and the influence triggered by the sway motion can be explained as the Bessel function modulation of the ordinary sea clutter spectra. The obtained results have important implications in the application of shipborne HFSWR technology to ocean remote sensing and target detection.展开更多
高精度雷达散射截面(RCS)测量对背景环境具有较高要求,当背景环境存在较强干扰时,通过背景矢量对消难以消除杂波影响。提出基于成像提取的高精度RCS测量方法,从背景杂波中分离和提取出目标的散射信号,从而提高了测量的精度。首先推导了...高精度雷达散射截面(RCS)测量对背景环境具有较高要求,当背景环境存在较强干扰时,通过背景矢量对消难以消除杂波影响。提出基于成像提取的高精度RCS测量方法,从背景杂波中分离和提取出目标的散射信号,从而提高了测量的精度。首先推导了像与RCS的数学关系,然后利用转台模式下的测量回波进行成像处理,得到目标区域的二维像;从成像区域中提取目标的二维像,通过波谱变换和定标获得目标的RCS。仿真结果表明,该方法对于具有干扰情况下的RCS测量,可以改善3~5 d B的测试精度,并且能够对弱散射目标进行测量。实验结果表明了成像提取方法的有效性和准确性。展开更多
基金supported by the National Basic Research Program of China(973 Program)(2010CB731905)
文摘The exact radar cross-section （RCS） measurement is difficult when the scattering of targets is low. Ful polarimetric cali-bration is one technique that offers the potential for improving the accuracy of RCS measurements. There are numerous polarimetric calibration algorithms. Some complex expressions in these algo-rithms cannot be easily used in an engineering practice. A radar polarimetric coefficients matrix （RPCM） with a simpler expression is presented for the monostatic radar polarization scattering matrix （PSM） measurement. Using a rhombic dihedral corner reflector and a metal ic sphere, the RPCM can be obtained by solving a set of equations, which can be used to find the true PSM for any target. An example for the PSM of a metal ic dish shows that the proposed method obviously improves the accuracy of cross-polarized RCS measurements.
基金supported by the National Science Fund for Young Scientists of China(6130214861571011)
文摘We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere, the radar cross section(RCS)of different metallic spheres is given at terahertz frequencies. The investigation of the RCS of polished metallic spheres shows the normalized RCS is always same to the metals’ normal incidence reflectivity when the sphere becomes electrically large. The metals which have high reflectivity(such as Al, Cu, Ag and Au) show that the corresponding RCS of the spheres is almost πa2 in terahertz band. The sphere’s RCS of the transition metal such as Fe begins to decrease obviously since the far infrared.
基金supported by the National Natural Science Foundation of China(61471144)
文摘This paper studies the development on the first order sea clutter cross section for bistatic high frequency surface wave radar (HFSWR). Based on the received first order electric field expression, a closed-form of cross sections is derived to account for the case of receiving antenna array being mounted on the shipborne platform. The uniform linear motion and sway motion components are assumed to be responsible for the observed differences in comparison with the bistatic fixed antenna case. Correspondingly, simulations are conducted to study the sea clutter spectral characteristics for these two cases versus different system parameters and sea state conditions. It is shown numerically that the forward motion component will spread the Bragg lines severely and the influence triggered by the sway motion can be explained as the Bessel function modulation of the ordinary sea clutter spectra. The obtained results have important implications in the application of shipborne HFSWR technology to ocean remote sensing and target detection.
文摘高精度雷达散射截面(RCS)测量对背景环境具有较高要求,当背景环境存在较强干扰时,通过背景矢量对消难以消除杂波影响。提出基于成像提取的高精度RCS测量方法,从背景杂波中分离和提取出目标的散射信号,从而提高了测量的精度。首先推导了像与RCS的数学关系,然后利用转台模式下的测量回波进行成像处理,得到目标区域的二维像;从成像区域中提取目标的二维像,通过波谱变换和定标获得目标的RCS。仿真结果表明,该方法对于具有干扰情况下的RCS测量,可以改善3~5 d B的测试精度,并且能够对弱散射目标进行测量。实验结果表明了成像提取方法的有效性和准确性。
