基于抛物方程的海陆环境信号时延与到达角估计

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

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。

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.