飞机超低空目标多径效应探测仿真研究
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摘要
在超低空目标探测问题的研究中,多径效应使雷达产生了探测盲区,限制了探测区域。为了有效探测超低空目标,研究多径效应对其探测距离的影响,提出了一种有效抑制多径效应的探测方法。采用物理光学法,结合等效电磁流法,计算出目标的直接散射场,并根据四路径模型,计算出介质微粗糙面与其上方三维导体目标的复合电磁散射。然后结合雷达距离方程,定义出归一化探测距离的概念,可用来作为分析多径效应对探测距离影响的依据。最后利用粗糙度、频率、极化特性等参量变化对多径效应进行仿真。仿真分析表明:当粗糙系数较小时,通过提高照射波频率、选用垂直极化波等方式可以有效抑制超低空目标的多径效应,为飞机超低空目标优化探测提供了参考。
To detect the target in super low altitude with effect and investigate the influence of multipath effect on the radar detection range,a target detection method is proposed to suppress the multipath effect. The EM scattering of the target is calculated by utilizing physical optics and combining with equivalent current method. Based on the four-path model,the electromagnetic composite scattering from a three- dimensional perfectly electric conducting target on a randomly rough dielectric surface is calculated. Then the concept of normalized detection range is defined,thus the evidence of analyzing the impact of multipath effect on the radar detection range is obtained,which is associated with the radar range equation. Ultimately,the impact of multipath effect is discussed on the parameters,such as roughness coefficient,frequency and polarization of the incident wave. The simulation result illustrate that,when the roughness coefficient is minor,the multipath effect could be suppressed by increasing frequency of the incident wave or choosing vertically polarized wave.
To detect the target in super low altitude with effect and investigate the influence of multipath effect on the radar detection range,a target detection method is proposed to suppress the multipath effect. The EM scattering of the target is calculated by utilizing physical optics and combining with equivalent current method. Based on the four-path model,the electromagnetic composite scattering from a three- dimensional perfectly electric conducting target on a randomly rough dielectric surface is calculated. Then the concept of normalized detection range is defined,thus the evidence of analyzing the impact of multipath effect on the radar detection range is obtained,which is associated with the radar range equation. Ultimately,the impact of multipath effect is discussed on the parameters,such as roughness coefficient,frequency and polarization of the incident wave. The simulation result illustrate that,when the roughness coefficient is minor,the multipath effect could be suppressed by increasing frequency of the incident wave or choosing vertically polarized wave.
引文
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[10]J T Johnson.A numerical study of scattering from an object above a rough surface[J].IEEE Trans.on Antennas and Propagation,2002,50(10):1361-1367.
[2]E A Shtager.An estimation of sea surface influence on radar reflectivity of ships[J].IEEE Trans.on Antennas and Propagation,1999,47(10):1623-1627.
[3]刘庆林,夏海宝,安磊,栾韶徽.地海杂波下机载预警雷达探测仿真[J].计算机仿真,2015,32(1):40-45,121.
[4]梁步阁等.超宽带脉冲对超低空目标的探测特性及其外场试验[J].微波学报,2006,22:142-146.
[5]李磊,等.一种探测低飞目标的PD雷达仿真系统[J].系统工程与电子技术,2010,32(6):1131-1135.
[6]Wang Xuezhi,D Musicki.Low elevation sea-surface target tracking using IPDA type filters[J].IEEE Trans on AES,2007,43(2):759-774.
[7]阮颖铮.雷达截面与隐身技术[M].北京:国防工业出版社,1998.
[8]A Michaeli.Equivalent Edge Currents for Arbitrary Aspects of Observation[J].IEEE Trans.Antennas Propagat.,1984,32(3):252-258.
[9]许小剑,姜丹,李晓飞.时变海面舰船目标动态雷达特征信号模型[J].系统工程与电子技术,2011,33(1):42-47.
[10]J T Johnson.A numerical study of scattering from an object above a rough surface[J].IEEE Trans.on Antennas and Propagation,2002,50(10):1361-1367.