基于卷积神经网络的增强型罗兰包络提取方法

An envelope extraction method for eLoran signals based on convolutional neural networks

  • 摘要: 增强型罗兰(Enhanced Long-Range Navigation, eLoran)系统作为GNSS的可靠备份,可在GNSS拒止或强干扰场景下提供可靠的定位、导航与授时(positioning, navigation and timing, PNT)信息. 针对eLoran信号包络提取易出现失真的问题,本文提出了一种基于卷积神经网络(convolutional neural network, CNN)的包络提取方法,以增强低信噪比(signal-to-noise ratio, SNR)下eLoran信号包络提取的鲁棒性. 该方法利用仿真数据生成eLoran信号及对应包络,通过构建包含大尺度一维卷积核、批量归一化、最大池化及转置卷积等深层结构的CNN网络模型,将待处理含噪信号输入到模型中提取对应的包络信息. 实验统计结果显示,SNR在−10~0 dB区间内,所提方法的均方根误差(root mean square error, RMSE)与相关系数均显著优于带通联合希尔伯特变换法和正交解调低通滤波法. SNR为−10 dB时,所提方法的RMSE保持在0.098 2,相关系数高达0.926 3. 恒定SNR时,RMSE和相关系数的误差棒也最小. 这表明该方法在包络提取精度与抗噪性能方面具备显著优势,为eLoran系统的高精度时延测量提供了稳健的波形基础.

     

    Abstract: As a reliable backup to the GNSS, the Enhanced Long-Range Navigation (eLoran) system delivers credible positioning, navigation, and timing (PNT) information in GNSS-denied or severely interfered scenarios. To address the envelope distortion issue in eLoran signal extraction, a convolutional neural network (CNN)-based method was developed to improve extraction robustness under low signal-to-noise ratio (SNR) conditions. Simulated datasets were employed to generate eLoran signals and their corresponding ideal envelopes. A deep CNN model, integrated with large-scale one-dimensional convolutional kernels, batch normalization, max pooling, and transposed convolution, was constructed to directly extract envelope information from input noisy signals. Statistical results show that, within the SNR range of –10 dB to 0 dB, both the root mean square error (RMSE) and correlation coefficient of the proposed method are significantly superior to those of the band-pass filtering combined with Hilbert transform method and the quadrature demodulation low-pass filtering method. At an SNR of –10 dB, the RMSE of the proposed method remains at 0.098 2, and the correlation coefficient reaches 0.926 3. Furthermore, for any fixed SNR value, the error bars of both evaluation metrics are minimized. These findings demonstrate that the proposed method offers substantial advantages in extraction accuracy and anti-noise performance, providing a robust waveform foundation for high-precision time delay measurement in eLoran systems.

     

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