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| 一种基于FRFT的宽带LFM信号角度距离估计算法 |
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钟俊1,2,3, 徐凡丁1,2,3, 曾琦1,2,3, 刘星1,2,3
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1.四川大学电气工程学院 2.成都 3.610065
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| 摘要: |
| 传统的超分辨测角测距算法是将子空间分解算法从角度维拓展到距离维，面向窄带信号进行多维参数估计，计算复杂度高，在低信噪比和低快拍数条件下性能不佳。该文针对宽带线性调频信号( Linear Frequency Modulation, LFM)提出一种基于分数阶傅里叶变换的角度距离估计算法。首先利用LFM信号在分数阶傅里叶域上的能量聚集特性，推导出各阵元接收数据在分数阶傅里叶域上的修正峰值位置与阵元位置的线性关系，采用批量梯度下降法进行斜率拟合求得角度估计值，接着利用发射信号与阵列接收信号的时延关系求得距离估计值。通过估计的均方根误差与复杂度分析，与传统算法进行了对比，实验结果显示在低信噪比和低快拍数情况下该文算法估计效果优于传统算法，证明了所提算法的优异性能。 |
| 关键词: 角度距离估计 分数阶傅里叶变换 峰值位置 斜率拟合 |
| DOI： |
| 分类号:TN911.7 |
| 基金项目:四川省科技计划项目(2023NSFSC0480) |
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| An Angle-Range estimation algorithm of wideband LFM signal based on Fractional Fourier Transform |
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| Abstract: |
| The traditional super-resolution angle-range estimation algorithms extend the subspace decomposition methods from angle dimension to distance dimension, enabling multi-dimensional parameters estimation for narrowband signal, which are burdened with high computational complexity and estimation error. This paper proposes an Angle-Range estimation method for wideband linear frequency modulation (LFM) signal based on Fractional Fourier Transform. The linear relationship between the corrected peak position of received data from different array elements in FRF domain and the array elements' position is initially derived based on the energy aggregation characteristics of the LFM signal in FRF domain. The angle estimates are obtained using slope fitting through batch gradient descent method, followed by obtaining distance estimate using the delay relationship between the transmitted signal and the received signal. The root mean square error and complexity of the proposed method are compared with those of traditional algorithms. Experimental results demonstrate superior performance of the proposed algorithm over traditional methods under low signal-to-noise ratios and low number of snapshots. |
| Key words: Angle-Range estimation Fractional Fourier Transform peak position slope fitting |