共查询到20条相似文献,搜索用时 31 毫秒
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For the distributed targets arising in most synthetic aperture radar (SAR) images, it is the integrated sidelobe (ISL) energy rather than the peak sidelobe level (PSL) that governs the performance of the pulse compression processing. A sidelobe cancellation technique is suggested which reduces the ISL energy by eliminating a significant portion of the sidelobe pattern of the pulse compression output, while the PSL is presented at the optimal Barker-code level. The efficiency of this ISL reduction is proportional to the signal code length 相似文献
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In order to obtain better target identification performance, an efficient waveform design method with high range resolution and low sidelobe level for orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) radar is proposed in this paper. First, the wideband CP-based OFDM signal is transmitted on each antenna to guarantee large bandwidth and high range resolution. Next, a complex orthogonal design (COD) is utilized to achieve code domain orthogonality among antennas, so that the spatial diversity can be obtained in MIMO radar, and only the range sidelobe on the first antenna needs suppressing. Furthermore, sidelobe suppression is expressed as an optimization problem. The integrated sidelobe level (ISL) is adopted to construct the objective function, which is solved using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. The numerical results demonstrate the superiority in performance (high resolution, strict orthogonality, and low sidelobe level) of the proposed method compared to existing algorithms. 相似文献
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在雷达信号处理中,通过匹配滤波进行脉冲压缩可以获得最大化的信噪比,有效地减小了雷达回波中噪声对信号的影响。然而,脉冲压缩的输出具有较高的距离旁瓣,在气象雷达探测中,由于空间分布的散射粒子之间反射强度相差较大,弱散射粒子的回波容易掩没在强散射粒子的旁瓣中,因此有超低旁瓣的需求。本文主要研究了能够降低旁瓣的非线性调频(NLFM)波形和最小积分旁瓣水平(ISL)失配滤波器,分析了多普勒频移对其性能的影响,并在最小ISL滤波器的基础上通过进一步对滤波器系数加权的方法,使得在回波具有多普勒频移的情况下也能达到超低旁瓣的性能。 相似文献
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本文介绍用线性规划方法求解[4,3,0]反馈连接的、起始状态为1001的15位m序列相位编码信号的最小峰值旁瓣滤波器(LP滤波器)的计算结果。长度为15的LP滤波器的峰值旁瓣电平降到-21.47dB,比匹配滤波器改善7.49dB,当滤波器的长度增加时,LP滤波器可把峰值旁瓣抑制到更低电平。并介绍用声表面波(SAW)技术制作15位m序列相位编码信号(起始状态为1001)的LP滤波器,实验结果,其峰值旁瓣电平为-19dB,与理论值相差2.47dB。 相似文献
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Reflector sidelobe degradation due to random surface errors 总被引:2,自引:0,他引:2
It is well known that the sidelobe structure of a reflector antenna is highly susceptible to random surface errors, and that in most applications it is not adequate to investigate only the average behavior of the antenna. In this study, an attempt is made to determine the probability distribution of the sidelobe level of a reflector antenna subject to some random surface errors. Specifically, the random pattern function is considered and its sidelobe level studied using the level-upcrossing theory. Both the degradation of the maximum sidelobe and the degradation of the sidelobe region with respect to an International Radio Consultative Committee (CCIR) sidelobe envelope are obtained. The theoretical results are found in excellent agreement with those obtained by Monte Carlo simulations. Finally, some useful tolerance charts are presented. 相似文献
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针对传统的宽带MVDR自适应波束形成中,抑制干扰的同时会抬高旁瓣电平,且过多的线性约束会导致波束输出的SINR性能下降的问题,提出了一种基于SRV约束和稀疏约束的低旁瓣、高增益宽带自适应波束形成方法.该方法在窄带MVDR自适应波束形成基础上,通过增加波束图稀疏约束来降低波束的旁瓣电平,同时利用空间响应偏差(SRV)约束将窄带算法推广到宽带MVDR 自适应波束形成中,极大地降低了算法的复杂度,改善了波束输出的SINR 性能.与传统方法相比,该方法在降低宽带波束的旁瓣电平的同时,还具有良好的干扰抑制效果.数值仿真实验验证了该方法的有效性. 相似文献
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S. Alighale 《International Journal of Electronics》2013,100(10):1458-1466
P4 polyphase code is well known in pulse compression technique. For P4 code with length 1000, peak sidelobe level (PSL) and integrated sidelobe level (ISL) are ?36dB and ?16dB, respectively. In order to increase the performance, there are different reduction techniques to reduce the sidelobes of P4 code. This paper presents a novel sidelobe reduction technique that reduces the PSL and ISL to ?127dB and ?104dB, respectively. Also, other sidelobe reduction techniques such as Woo filter are investigated and compared with the novel proposed technique. Simulations and results show that the proposed technique produces a better peak side lobe ratio (PSL) and integrated side lobe ratio (ISL) than other techniques. 相似文献
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Chen Yujun 《电子科学学刊(英文版)》1988,5(4):307-311
This paper presents computation results of the minimum peak sidelobe filter (LP filter) for the 15-bitM-sequence phase coded signal with feedback connection [4,3,0] and initial condition 1001. The design of the filter resorts
to the linear programming method. The peak sidelobe level is reduced to −21.47 dB by the LP filter of length 15, and is 7.49
dB lower than that by the matched filter. The LP filter can suppress the peak sidelobe even more by increasing its length.
The minimum peak sidelobe filter for the 15-bitM-sequence phase coded signal (initial condition 1001) has been implemented with a surface acoustic wave (SAW) device. Experiments
show that the peak sidelobe level of the manufactured filter is −19 dB and, thus, only differs from the theoretical value
of −21.47 dB by 2.47 dB. 相似文献
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相控阵天线由于馈电误差的影响,旁瓣电平恶化,抗干扰能力降低。由于馈电误差随机分布,提出了采用数字统计特征分析旁瓣电平恶化情况的方法。论述了均值旁瓣电平和峰值旁瓣电平的基本原理。通过理论分析和数值模拟,计算了峰值旁瓣电平的概率密度分布,并给出了抑制旁瓣电平恶化的一些措施。 相似文献
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Applying a sparse constraint on the beam pattern has been suggested to suppress the sidelobe of the minimum variance distortionless response (MVDR) beamformer recently. To further improve the performance, we add a mixed norm constraint on the beam pattern. It matches the beam pattern better and encourages dense distribution in mainlobe and sparse distribution in sidelobe. The obtained beamformer has a lower sidelobe level and deeper nulls for interference avoidance than the standard sparse constraint based beamformer. Simulation demonstrates that the SINR gain is considerable for its lower sidelobe level and deeper nulling for interference, while the robustness against the mismatch between the steering angle and the direction of arrival (DOA) of the desired signal, caused by imperfect estimation of DOA, is maintained too. 相似文献
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WangFeixue OuGang ZhuangZhaowen 《电子科学学刊(英文版)》2004,21(1):33-36
A kind of novel binary phase code named sidelobe suppression code is proposed in this paper.It is defined to be the code whose corresponding optimal sidelobe suppression filter outputs the minimum sidelobes.It is shown that there do exist sidelobe suppression codes better than the conventional optimal codes-Barker codes.For example,the sidelobe suppression code of length 11 with filter of length 39 has better sidelobe level up to 17dB than that of Barker code with the same code length and filter length. 相似文献
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A formula is derived for the peak sidelobe level of a phased array in which the elements are randomly located. The parameters of the formula are the number and size of the array elements, size of the array, wavelength, beamsteering angle, and signal bandwidth. The theory is tested by measurement of the peak sidelobe of several hundred computer-simulated random arrays. Unlike the case for the conventional array the effect of spatial taper (nonuniform density of element location) upon the peak sidelobe level is minor. The peak sidelobe of the two-dimensional planar array is approximately 3 dB higher than that of the linear array of the same length and same number of elements. 相似文献
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Chu S.T. Pan W. Sato S. Maeda T. Little B. Kokubun Y. 《Photonics Technology Letters, IEEE》1998,10(3):391-393
An antiresonant reflecting optical waveguide (ARROW) type vertical coupler filter exhibiting low sidelobe characteristics is demonstrated. The sidelobe level of the filter has been suppressed by using an X-crossing arrangement to provide strength apodization along the device. The main sidelobe of the fabricated filter is measured to be less than -17 dB with the central wavelength in the 1.55-μm region 相似文献
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线性调频(LFM)信号是一种被广泛应用的大时宽带宽积信号,利用LFM信号的多样性可设计多输入多输出(MIMO)雷达的正交波形。该文针对现有波形相关函数存在的问题,以理论分析为基础,提出一种基于LFM时宽的发射波形,并给出了一种相应的正交波形设计方法。该方法以峰值旁瓣电平为准则,利用序列二次规划对各子脉冲LFM信号的时宽进行优化设计。仿真结果表明,与现有方法相比,所设计波形具有较低的自相关旁瓣电平和互相关电平。此外,通过数值实验分析了相关性能随波形个数及子脉冲个数的变化关系。 相似文献
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Minimization of the maximum sidelobe level for a given array geometry by phase-only adjustment of the element excitations is considered. Optimum phases are obtained by using a numerical search procedure to minimize the expression for the pattern sidelobe level with respect to the element phases. Results for both linear and planar arrays of equispaced elements are presented. The data suggests that optimum sidelobe level is a logarithmic function of array size, and optimum patterns have relative efficiencies that are typically somewhat greater than for comparable-amplitude tapered arrays. An analytic synthesis algorithm is presented for use on very large arrays for which the numerical search technique for the minimization of the sidelobe level is computationally impractical. This method produces patterns with characteristics similar to arrays synthesized using the numerical search method, i.e. relatively uniform angular distribution of energy in the sidelobe region, and generally decreasing maximum sidelobe level as the array size is increased 相似文献
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