共查询到19条相似文献,搜索用时 218 毫秒
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针对双极化气象雷达中非气象回波的滤除问题,该文提出一种基于谱极化参数(SPP)的杂波滤波方法。不同于传统时域或频域的杂波抑制方法,该方法根据气象和杂波在距离-多普勒(RD)域内的特征不同进行前者的保留和后者的抑制。首先利用频谱极化特征构造SPP,结合形态学方法,在RD域内生成一个2元掩模。基于面向对象的思想,将2元掩模标记为气象对象掩模和杂波对象掩模。然后引入谱宽作为额外的参数,筛选出所有气象对象掩模,将其进行叠加可以获取完整的气象信息,最终生成SPP杂波滤波器。实测X波段和C波段气象雷达数据验证了所提方法的有效性。与移动双重谱线性退极化比(MDsLDR)滤波器和基于时域的门限因子杂波抑制方法相比,SPP滤波器在保留弱气象信息方面效果更好。此外,该方法计算复杂度低,可以实时应用于同时发射同时接收(STSR)和交替发射同时接收(ATSR)双极化气象雷达。 相似文献
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针对双极化气象雷达中非气象回波的滤除问题,该文提出一种基于谱极化参数(SPP)的杂波滤波方法.不同于传统时域或频域的杂波抑制方法,该方法根据气象和杂波在距离-多普勒(RD)域内的特征不同进行前者的保留和后者的抑制.首先利用频谱极化特征构造SPP,结合形态学方法,在RD域内生成一个2元掩模.基于面向对象的思想,将2元掩模标记为气象对象掩模和杂波对象掩模.然后引入谱宽作为额外的参数,筛选出所有气象对象掩模,将其进行叠加可以获取完整的气象信息,最终生成SPP杂波滤波器.实测X波段和C波段气象雷达数据验证了所提方法的有效性.与移动双重谱线性退极化比(MDsLDR)滤波器和基于时域的门限因子杂波抑制方法相比,SPP滤波器在保留弱气象信息方面效果更好.此外,该方法计算复杂度低,可以实时应用于同时发射同时接收(STSR)和交替发射同时接收(ATSR)双极化气象雷达. 相似文献
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针对瞬态极化雷达发射波形自相关和互相关特性相互制约的矛盾,本文对瞬态极化雷达的接收滤波器进行优化设计,以减小相同极化通道的距离旁瓣和不同极化通道之间的相互串扰,提高全极化雷达的检测和估计性能.建立了瞬态极化雷达回波信号模型,分析了目标极化散射矩阵估计的误差来源,根据估计误差函数建立优化模型,通过凸优化求解对不同极化通道的滤波器进行优化设计.分析了单个静止点目标、运动目标和多目标情况下滤波器的性能,并给出了仿真结果.最后,利用实测数据验证了本文方法的有效性. 相似文献
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具有双极化接收能力的雷达利用极化滤波手段能够抑制波束主瓣内的干扰信号.然而多径等传播环境效应会对干扰信号的极化特性产生扰动,影响实际接收信号的极化度,同时影响极化滤波器的干扰抑制性能.本文基于工程中对干扰抑制极化滤波器性能分析的需求,分别在理想条件及环境扰动条件下建立了用于描述干扰抑制极化滤波器性能的数学模型,仿真分析了极化滤波器的干扰抑制性能同干噪比、干扰极化状态以及环境扰动系数间的关系.随后为改善环境扰动影响下干扰抑制性能,提出了一种新的基于天线主辅阵联合的极化滤波的方法.最后通过极化雷达抗干扰实验不仅验证了极化滤波器性能表征模型的正确性,同时还在环境扰动条件下对比了两种滤波器性能,结果表明新的滤波方法在该扰动条件下干扰抑制方面的优势. 相似文献
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移动通信基站的下行信号会影响UHF波段雷达的目标探测和跟踪,开展基站干扰环境的极化特性测量与分析,是利用极化处理手段对抗此类干扰的基础和依据。该文首先建立了UHF波段双极化雷达对基站信号接收模型,推导了极化比和极化度估计量的概率密度函数用以表征干扰环境极化统计特性;而后分别开展了对单个基站和多个基站的雷达外场接收测量试验,实验结果说明了确定性描述方法仅适用于表征极化度较高的单个基站信号,对多基站或极化度较低的情形则不再适用。通过实测数据与理论模型的拟合验证了该文给出的统计模型在描述两种场景下干扰信号统计特性上的正确性和适用性。 相似文献
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瞬态极化雷达采用同时发射、同时接收的测量体制,可以利用正交极化通道的单次回波信号测量目标极化散射矩阵。首先给出了窄带瞬态极化雷达信号模型和信号处理方法;然后详细分析了两类瞬态极化雷达信号波形(频移脉冲矢量波形和正负调频斜率LFM矢量波形)的测量性能;最后用国防科技大学研制的X波段瞬态极化雷达系统开展外场实验,实验结果表明:与分时极化测量结果相比,两者的相对幅度测量结果差异小于2 dB,相对相位测量结果差异小于10,°从而验证了瞬时极化测量的有效性。 相似文献
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极化滤波利用干扰信号和目标信号的极化状态差异,可有效抑制有源压制干扰,然而,现有极化雷达需要两路发射通道和接收通道,存在系统复杂、实现代价高等诸多困难。该文提出了一种新体制极化雷达模型极化二元阵雷达,该系统仅需一路发射通道和接收通道即可实现极化测量。基于极化二元阵天线的空域极化特性,建立了有源压制干扰、目标回波的接收信号模型,研究了抑制有源压制干扰的空域虚拟极化滤波算法,仿真实验结果表明:对于窄带噪声调频干扰,信干比(SIR)改善因子能达到20 dB以上。 相似文献
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高频地波雷达多干扰的极化抑制 总被引:17,自引:1,他引:16
天波电台干扰是高频地波雷达所面临的主要干扰,虽然采用频率捷变技术可以躲避干扰,但是当短波电台十分密集时很难找到合适工作频段的,而且当存在与雷达回波同方向入射的干扰时,空间滤波技术也无能为力。利用极化技术可以较好地解决以下问题,但目前高频地波雷达中的极化滤波还只限于对单干扰的抑制,为了进一步拓宽雷达的工作频段,本文研究了多干扰的极化抑制问题,给出了一种在频域同时提取多干扰极化特征的方法,并根据这一方法构造了一种频域极化滤波器,使得频带互不重叠的多个干扰可以被有效滤除,而不受极化度的限制,从而克服了以往极化滤波器只能处理极化度较高的干扰的特点。理论和仿真实验证明了算法的有效性。 相似文献
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Mead J.B. Pazmany A.L. Sekelsky S.M. McIntosh R.E. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1994,82(12):1891-1906
Millimeter-wave radars have been used since the early 1950s to study clouds and precipitation, but until recently these early instruments were limited to simple backscatter power measurements and were plagued by hardware problems. However, development of solid-state millimeter-wave componentry and high-power klystron amplifiers has spurred the evolution of reliable, coherent radars operating up to 95 GHz. In addition, advances in digital signal processing technology have resulted in single-card processors that can simultaneously execute algorithms to compute reflectivity, Doppler, and polarimetric quantities in real time. A review of the current state of the art in millimeter-wave cloud radars is presented, including a discussion of transmitters, antennas, and receiver components. Two radar systems built by the University of Massachusetts are described, including a mobile, dual-frequency (33- and 95-GHz) polarimetric radar, and an airborne 95-GHz polarimetric radar that was recently flown in a cooperative experiment with the University of Wyoming. Spaceborne applications are also discussed, especially the use of satellite-based 95-GHz radars for measuring the vertical distribution of clouds 相似文献
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Phased Array Radar Polarimetry for Weather Sensing: A Theoretical Formulation for Bias Corrections 总被引:1,自引:0,他引:1
《Geoscience and Remote Sensing, IEEE Transactions on》2009,47(11):3679-3689
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Nashashibi A.Y. Sarabandi K. Frantzis P. De Roo R.D. Ulaby F.T. 《Geoscience and Remote Sensing, IEEE Transactions on》2002,40(8):1777-1786
With the advent of high-frequency radio frequency (RF) circuits and components technology, millimeter-wave (MMW) radars are being proposed for a large number of military and civilian applications. Accurate and high-resolution characterization of the polarimetric radar backscatter responses of both clutter and man-made targets at MMW frequencies is essential for the development of radar systems and optimal detection and tracking algorithms. Toward this end, a new design is developed for ultrafast, wide-band, polarimetric, instrumentation radars that operate at 35 and 95 GHz. With this new design, the complete scattering matrix of a target (magnitude and phase) can be measured over a bandwidth of 500 MHz in less than 2 /spl mu/s. In this paper, the design concepts and procedures for the construction and calibration of these radars are described. In addition, the signal processing algorithm and data-acquisition procedure used with the new radars are presented. To demonstrate the accuracy and applicability of the new radars, backscatter measurements of certain points and distributed targets are compared with their analytical radar cross section (RCS) and previously measured /spl sigma//spl deg/ values, respectively, and good agreements are shown. These systems, which can be mounted on a precision gimbal assembly that facilitates their application as high-resolution imaging radar systems, are used to determine the MMW two-way propagation loss of a corn field for different plant moisture conditions. 相似文献
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多普勒天气雷达的交替PRT地物滤波算法 总被引:1,自引:0,他引:1
交替脉冲技术是多普勒天气雷达解速度模糊的一种方法,但是对于交替脉冲技术中的非均匀时间序列,由于没有行之有效的地杂波滤波器,因而阻碍了这种方法在多普勒天气雷达中的实际应用。该文研究了新的谱处理地物滤波器,它从频域滤除地杂波的谱分量,并利用幅度反卷积和幅度谱校正重建天气回波的频谱,然后从重建的频谱进行多普勒参数的估计。与时域地物滤波器相比,它不仅解决了滤波器频率响应中出现错误对消区的问题,而且还可以在地杂波存在时,在扩展的不模糊速度范围内更准确地估计出多普勒参数,使交替重复周期解速度模糊技术更有实用价值。 相似文献
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All current incoherent backscatter radars can make mesospheric or D region measurements (60-90-km altitude) under at least some conditions. This paper, which is tutorial in nature, develops the basic concepts of incoherent scatter radar measurements in the D region and the conditions under which measurements are possible are derived and shown for each radar. Conditions examined include overall system sensitivity, electron and ion spectral line widths and power distributions, and time/height averaging effects. The appropriate form of the radar equation is derived and calibration of the radar system is discussed along with the various aspects of signal processing involved. Total power only and combined total power and ion line spectral measurements are described in terms of ease of use, applicability to various radars, and parameters of aeronomic interest derivable from the measurements. 相似文献
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综述了多普勒天气雷达双发双收、单发双收、单发单收微波系统的系统体系、技术特点、功能模块、优缺点等,提出了多普勒天气雷达微波系统技术体系和功能模块的研发准则,比较了国内外已经开发成功的S/C/X各波段多普勒天气雷达微波系统的系统体系及功能,指出了多普勒天气雷达微波系统的发展方向。 相似文献