干涉阵列米波雷达的低仰角高精度估计方法

High accuracy estimation of low elevation angle based on the interferometric array in the VHF radar

针对米波雷达低仰角估计的难题,结合干涉技术和超分辨算法的优点,提出了干涉阵列米波雷达的高精度低仰角估计方法.该方法首先利用干涉结构扩展阵列孔径,再将常规的空间平滑算法推广到干涉阵,提出了干涉阵的空间平滑方法,然后应用其实现低仰角多径信号的解相干,最后利用双尺度酉ESPRIT算法得到低仰角的高精度估计.仿真结果和实测数据验证了干涉阵列的前后向空间平滑方法及干涉阵列的高精度低仰角估计方法的有效性,并分析了该方法存在的信噪比门限与基线模糊门限的产生原因.

Due to the difficulty with the measurement of the low elevation angle on targets near the horizon for VHF radar,combining the interferometry and the advantages of superresolution algorithms,a novel method to estimate low elevation angles with high accuracy based on the interferometric array is proposed.The interferometric array extends the array aperture with small pieces of hardware.The interferometric forward/backward spatial smoothing technique is proposed from the conventional spatial smoothing algorithm for the uniform linear array and is used to decorrelate the ground multipath signal.Then we obtain highly accurate estimation of the low elevation using the dual-size unitary ESPRIT algorithm.Simulation results and real data demonstrate the efficacy of the interferometric forward/backward spatial smoothing technique and the proposed method,with the reasons why there exist the SNR threshold and baseline ambiguity threshold in the proposed method analyzed.