机载分布式相参射频探测系统杂波特性研究
发布时间:2018-08-20 16:33
【摘要】:机载分布式相参射频探测系统作为新一代雷达体制,具有重大的军事应用前景。相比于机载相控阵雷达,机载分布式相参射频探测系统具有探测视场宽、分辨率高、自由度高、抗干扰能力强等优势。然而,正交波形的发射和布阵结构引起杂波谱特性发生变化,高自由度增加了杂波处理的样本需求量和计算量。本文以机载分布式相参射频探测系统为背景,重点研究机载分布式相参射频探测系统杂波特性及杂波抑制方法。论文研究了机载分布式相参射频探测系统杂波特性。收发阵列单元分别共线等间距布阵,以发射频率正交信号为例,建立了杂波模型;分别从多普勒频率维、角度-多普勒频率维及多普勒频率-距离维分析了杂波的多普勒特性、空时特性及时频特性。在正侧视阵列情况下,杂波多普勒频率的变化与距离无关,但是非正侧视阵列情况,多普勒频率与角度维成二次曲线关系且受近距离影响很大;分析了系统参数如CNR、采样单元数和载频步进频率对杂波特征谱的影响,及误差如多普勒模糊、载机偏航和杂波扰动对杂波特征谱和功率谱的影响。误差导致杂波去相关,使得杂波功率谱展宽、杂波自由度增大。进一步提出了空时多通道降维杂波抑制方法。通过分析现有的杂波抑制方法,并比较处理器性能,提出了降低运算量的空时多通道处理方法。将发射阵列-接收阵列-时间3维的处理变为合成阵列-时间2维的处理,经FFT后选择若干个相邻的波束通道和多普勒通道进行空时联合处理。仿真结果表明,该方法在低杂噪比环境下,不但能获得同EFA方法和3DJDL方法相同的处理效果,而且具有更低的计算量和样本需求量。最后从杂波改善因子、剩余杂波功率、计算量和样本需求量几个方面比较了不同杂波处理方法的性能。
[Abstract]:As a new generation radar system, airborne distributed coherent radio frequency detection system has a great prospect of military application. Compared with the airborne phased array radar, the airborne distributed radio-frequency detection system has the advantages of wide field of view, high resolution, high degree of freedom and strong anti-jamming ability. However, the transmission of orthogonal waveforms and the structure of arrays cause changes in the spectral characteristics of clutter, and the high degree of freedom increases the demand for samples and the amount of computation for clutter processing. In this paper, the clutter characteristics and clutter suppression methods of airborne distributed coherent radiofrequency detection system are studied with emphasis on the background of airborne distributed coherent radio frequency detection system. The clutter characteristics of airborne distributed coherent radio frequency detection system are studied in this paper. The clutter model is established by collinear equidistant array of transceiver array units, and the Doppler characteristics of the clutter are analyzed from Doppler frequency dimension, angle Doppler frequency dimension and Doppler frequency range dimension, respectively, taking the transmitted frequency orthogonal signal as an example, and analyzing the Doppler characteristics of the clutter from the Doppler frequency dimension, the angle Doppler frequency dimension and the Doppler frequency range dimension, respectively. Space-time characteristic-time-frequency characteristic. In the case of positive side-looking array, the Doppler frequency of clutter is independent of distance, but in the case of non-positive side-looking array, the relationship between Doppler frequency and angle dimension is conic and is greatly affected by the close-range. The effects of system parameters such as CNR, the number of sampling units and the step frequency of carrier frequency on the characteristic spectrum of clutter, as well as the effects of errors such as Doppler blur, carrier yaw and clutter disturbance on the characteristic spectrum and power spectrum of clutter are analyzed. The error causes the clutter to decorrelate and widen the power spectrum of the clutter and increase the degree of freedom of the clutter. Furthermore, a space-time multi-channel reduced-dimensional clutter suppression method is proposed. By analyzing the existing clutter suppression methods and comparing the performance of the processor, a space-time multichannel processing method is proposed to reduce the computational complexity. The processing of transmitting array, receiving array and time 3 D is changed into synthetic array 2 D processing. After FFT, several adjacent beam channels and Doppler channels are selected for space-time joint processing. The simulation results show that the proposed method can not only achieve the same processing effect as EFA and 3DJDL methods, but also have lower computational complexity and sample requirement under low clutter noise ratio environment. Finally, the performance of different clutter processing methods is compared in terms of clutter improvement factor, residual clutter power, calculation amount and sample demand.
【学位授予单位】:电子科技大学
【学位级别】:硕士
【学位授予年份】:2014
【分类号】:TN957.51
[Abstract]:As a new generation radar system, airborne distributed coherent radio frequency detection system has a great prospect of military application. Compared with the airborne phased array radar, the airborne distributed radio-frequency detection system has the advantages of wide field of view, high resolution, high degree of freedom and strong anti-jamming ability. However, the transmission of orthogonal waveforms and the structure of arrays cause changes in the spectral characteristics of clutter, and the high degree of freedom increases the demand for samples and the amount of computation for clutter processing. In this paper, the clutter characteristics and clutter suppression methods of airborne distributed coherent radiofrequency detection system are studied with emphasis on the background of airborne distributed coherent radio frequency detection system. The clutter characteristics of airborne distributed coherent radio frequency detection system are studied in this paper. The clutter model is established by collinear equidistant array of transceiver array units, and the Doppler characteristics of the clutter are analyzed from Doppler frequency dimension, angle Doppler frequency dimension and Doppler frequency range dimension, respectively, taking the transmitted frequency orthogonal signal as an example, and analyzing the Doppler characteristics of the clutter from the Doppler frequency dimension, the angle Doppler frequency dimension and the Doppler frequency range dimension, respectively. Space-time characteristic-time-frequency characteristic. In the case of positive side-looking array, the Doppler frequency of clutter is independent of distance, but in the case of non-positive side-looking array, the relationship between Doppler frequency and angle dimension is conic and is greatly affected by the close-range. The effects of system parameters such as CNR, the number of sampling units and the step frequency of carrier frequency on the characteristic spectrum of clutter, as well as the effects of errors such as Doppler blur, carrier yaw and clutter disturbance on the characteristic spectrum and power spectrum of clutter are analyzed. The error causes the clutter to decorrelate and widen the power spectrum of the clutter and increase the degree of freedom of the clutter. Furthermore, a space-time multi-channel reduced-dimensional clutter suppression method is proposed. By analyzing the existing clutter suppression methods and comparing the performance of the processor, a space-time multichannel processing method is proposed to reduce the computational complexity. The processing of transmitting array, receiving array and time 3 D is changed into synthetic array 2 D processing. After FFT, several adjacent beam channels and Doppler channels are selected for space-time joint processing. The simulation results show that the proposed method can not only achieve the same processing effect as EFA and 3DJDL methods, but also have lower computational complexity and sample requirement under low clutter noise ratio environment. Finally, the performance of different clutter processing methods is compared in terms of clutter improvement factor, residual clutter power, calculation amount and sample demand.
【学位授予单位】:电子科技大学
【学位级别】:硕士
【学位授予年份】:2014
【分类号】:TN957.51
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