用于高频地波雷达阵列天线的孤立大目标分层校准算法

Hierarchical calibration algorithm using isolated large targets on an HFGW radar antenna array

高频地波雷达接收阵列不可避免地存在幅度和相位误差,这时天线方向图会产生歧变并使杂波对消算法失效。校准方法有采用辅助信源、建立阵列模型进行参数估计、利用噪声或杂波做为校准源等,缺点分别为成本高、实时性差、不能校准相位误差。针对以上问题,该文提出了孤立大目标分层校准算法。首先将阵列分成若干子阵,然后选取在空域和Doppler域都具有唯一性的大信噪比目标作为校准源,采用改进的噪声子空间拟合法或者相差校准法对各子阵的幅相误差进行校准,最后通过对各子阵误差矢量的融合得到统一的误差矢量,从而实现整个阵列的幅相校准。校准后阵列天线的幅度误差、相位误差和波束方向图旁瓣均显著减小。理论和实践都表明,孤立大目标分层校准算法比传统算法在实时性和精度方面都得到了大幅度的提高。

High frequency ground wave（HFGW） radar antenna arrays always have amplitude-phase errors; thus, when the antenna pattern is changed, the clutter cancellation algorithm must be recalibrated. The existing calibration methods include using an auxiliary source, building an array model for parameter estimation, and using the noise or clutter as a calibration source. However, the first method is expensive, the second has poor real-time performance, and the third cannot calibrate the phase error. This paper presents a hierarchical calibration algorithm using isolated large targets. The array is divided into several subarrays with a high SNR target which is unique in the spatial and Doppler domains as the calibration source.Then, the errors in each subarray are calibrated using the improved noise subspaee fitting method or the phase difference calibration method to get a uniform error vector by integrated each subarray error vector to calibrate the entire array＇s amplitude and phase errors. The calibration significantly reduces the amplitude error, phase error and the sidelohe of the antenna pattern. Both theoretical results and tests show that this calibration method greatly improves the accuracy and real-time response than the traditional algorithm.