面向海洋表面流场探测的紧凑型高频地波雷达天线校准方法研究

High-frequency (HF) radars can real-time monitor the sea surface current over a large area even in severe weather. The compact HF radar, which adopts the monopole-cross-loop antenna as receving antenna, is prefered by the oceanic radar user because it is smaller and easier installation and maintain than the phased array radar. The performance of the compact HF radar in ocean surface current measurement is dominated by the calibration method used to correct the system error within the receiving channels. The existing calibration methods without any know sources do not take the influence of the antenna pattern distortion into account, so that these calibration methods are often invalid in practical application. On the other hand, the existing calibration methods with know sources, which are based on the measured actual antenna patten, often produce ocean surface current mappings with low and uneven data rate, and local gaps within these current mappins. Therefore, this project is aimed at studying the calibration method without any know sources for single and dual monopole-cross-loop antenna array in compact HF radar system under the condition of the antenna pattern of monopole-cross-loop antenna being distorted, and also studying the measured antenna pattern based calibration method. The results of this project must be a substantial breakthrough in ocean surface current observation for the compact HF radar, so that this radar system can make more contribution to economic construction and coastal defense, and generate significant economic and social benefits for our contry.

高频地波雷达能够实现实时、全天候、大范围的海洋表面流场观测。采用单极子交叉环作为接收天线的紧凑型高频地波雷达因占地空间少、易于架设和维护等特点而备受高频海洋雷达用户的青睐。影响紧凑型高频雷达系统的海洋表面流场观测性能的最大因素在于其单极子交叉环接收天线系统的校准。现有的无源校准方法没有考虑天线本身方向图畸变带来的影响，导致校准算法在实际应用中经常失效；而现有的基于实测天线方向图的有源校准方法得到的海洋表面流场往往存在数据率低、数据率分布不均匀、流场中局部区域总是出现数据缺失等问题。为此，本项目将研究适用于方向图畸变情况下的一元和二元单极子交叉环天线阵的无源校准方法以及基于实测天线方向图的单极子交叉环天线有源校准方法。本项目的研究成果可望为紧凑型高频地波雷达海流探测性能带来实质性的突破，使该雷达系统更好地服务于我国经济建设和海防事业，产生重大的经济和社会效益。

高频地波雷达作为一种高效的海洋表面环境监测工具正被广泛地应用于海洋表面海流场、海浪场和风场的实时、大范围观测。相较于采用传统相控阵天线作为接收天线的阵列型高频地波雷达系统，采用单极子交叉环天线作为接收天线的紧凑型高频地波雷达系统因占地空间少、成本低、易于架设和维护等特点而更受高频地波雷达用户的青睐。目前，全世界正在运行的高频地波雷达系统有85%以上的是这种紧凑型雷达系统。本项目针对紧凑型高频地波雷达的海流提取问题研究了单极子交叉环天线方向图的畸变及其导致的海流信号方位角估计误差，并进一步地提出了天线的无源校准方法用以消除信号方位角估计误差，进而提升雷达的海流测量性能。此外，本项目还针对一阶海洋回波的提取方法进行了研究，提出了一种更加稳健的一阶海洋回波提取方法，用以弥补现有方法在海况剧烈波动时的性能下降的缺点，并通过实际试验验证了该方法的有效性。以上工作对于提升高频地波雷达的性能研究和促进高频地波雷达的应用推广都具有积极的作用。