基于抛物方程的海陆环境信号时延与到达角估计

针对复杂海陆环境中的无线信号传播预测问题，研究了适用于抛物方程的信号时延与到达角估计方法。将自由空间中抛物方程轴向波前信号视为本地副本信号，然后利用信号的自相关特性，将接收信号与副本信号进行互相关运算，最后通过相关函数的峰值检索，得到脉冲信号在复杂环境中传播的附加时延。采用数值算例，验证了该方法的正确性和有效性。此外，采用多重信号分类算法，由抛物方程构建接收阵列的协方差矩阵，并对其进行特征值分解，然后利用信号子空间和噪声子空间的正交性，实现复杂环境中的信号到达角估计。仿真结果表明，相比于传统的平面波谱方法，该方法具有更高的多径分辨率。基于上述方法，并结合数字地图，在典型的海陆环境中进行了仿真实验，分析了蒸发波导对脉冲信号传播时延和到达角的影响。

Estimation of time-delay and direction of arrival in complex sea and land environment using parabolic equation method

Time-delay and direction of arrival are two important signal parameters in wireless positioning, radar detection, and target tracking applications. In this paper, a parabolic equation method is presented to simulate the propagation of pulse signals in the sea-to-land environment and to estimate the characteristic parameters of the signals considering irregular terrains and atmospheric refraction. A correlation function method is presented to extract the time-delay of the received signal from parabolic equation. Besides, a multiple signal classification algorithm is used to estimate the direction of arrival of signals, which provides a higher resolution compared with the traditional wave spectral method. Numerical examples are given to illustrate the correctness of the presented methods. Finally, with the presented methods, simulation experiments in a typical sea and land environment are presented to analyze the effects of evaporation duct on signal's delay and direction of arrival.