【作者】 谢俊好；

【导师】 刘永坦；

【作者基本信息】 哈尔滨工业大学 ， 通信与信息系统， 2001， 博士

【摘要】 高频地波雷达（HFSWR）利用垂直极化电磁波沿海面绕射传播的机理，既能实现对海上舰船和低空飞行目标的超视距探测，又可用于海态遥感等民用事业。舰载HFSWR除具有岸基HFSWR的特点外，更突出的优势在于其灵活机动性，其研制近年来引起广泛关注。相比于岸基HFSWR，舰载HFSWR信号处理的难点在于一阶海杂波展宽谱中舰船目标的检测与估值，本文对此进行了深入研究。 首先理论分析了舰载HFSWR一阶海杂波谱的展宽机理，给出其展宽数学模型，这些已被舰载HFSWR数据采集试验所获得的实测海杂波数据处理结果所证实。平台运动时，雷达分辨单元内不同方向的一阶海杂波回波被附加不同的多普勒频移，使得岸基情形时强大的一阶Bragg峰（单频）被展宽，因此影响展宽谱中船目标检测的主要干扰为具有相同多普勒频率但方位不同的一阶海杂波，这也是全文的基础与出发点。 类似于机载预警雷达（AEW）的地杂波抑制，本文将天线相位中心偏置（DPCA）技术推广并应用于舰载HFSWR的一阶海杂波抑制。考虑到实际平台运动速度的波动，提出了通过空域插值获得等效阵元信号进行DPCA处理的方法。计算机仿真结果表明：当平台运动速度与理想速度偏离较小时，可通过空域插值获得较好的杂波抑制效果。进一步，基于阵列采样信号的时空等价性，本文还分析了基于时域插值进行DPCA处理的方法，结果表明只要平台匀速直线运动，通过时域插值就可获得较好的杂波抑制效果，这大大放松了空域插值方法对平台运动速度的限制。理论证明在理想条件下上述DPCA处理对单频的正负一阶Bragg峰是最优的。 DPCA是一种最简单的空时二维自适应处理，它需要满足特殊条件。由于舰载HFSWR的一阶海杂波具有时空耦合的二维谱，因此最佳杂波抑制应采用空时自适应处理（STAP）。本文利用卡亨南—洛厄维展开（KLE）对[O，T₀]观测时间、带宽为W的限带谱连续随机过程进行展开，得到其特征谱的解析表达式，即大特征值个数为2WT₀+1。进一步通过理论证明及计算机模拟，将连续限带谱的结论推广至离散序列情形，给出了机载预警雷达二维地杂波特征谱的表达式。针对舰载HFSWR的一阶Bragg展宽谱等带通谱情形，理论分析得到了其特征谱表达式，这与实测数据处理结果非常一致，可用于空时二维自适应处理结构的简化。 综合前面分析并考虑到系统简单化与实时性，本文提出了时域多普勒滤波更多还原

【Abstract】 High Frequency Surface Wave Radar (HFSWR), utilizing a vertical polarization electromagnetic wave that follows the curvature of the earth along the air-water interface with low propagation loss on highly conductive ocean surface, could detect and track targets beyond the horizon such as vessels on the sea and aircrafts at a low altitude. It provides a new technique for remote sensing of sea state and traffic control over the sea. Besides these characteristics, shipborne HFSWR also provide agility and maneuverability, which has attracted a number of countries’ attention in decade’s. Compared with the ashore HFSWR, the difficulty of signal processing in shipborne HFSWR is how to detect and estimate ships whose Doppler frequencies appeared in the spreading domain of the Bragg lines. The main purpose of this dissertation is to solve the problem both in theory and in practice.The dissertation firstly analyze the spreading mechanism of the Bragg line in shipborne HFSWR and present a mathematical spreading model, which are verified by experimental results from the shipborne HFSWR data collection experiment conducted in 1998. It is the vectorial summation of the platform motion with that of the clutter return from different directions within the radar range cell that results in spreading of the Bragg line. Therefore, the main interference for detection of targets in the spreading domain is the first order sea clutter returns from the direction different from targets’ azimuth but with the same Doppler frequency with consideration of platform motion.By analogy with the ground clutter rejection in Airborne Early Warning (AEW) radar, Displaced Phase Center Antenna (DPCA) technique is extended for suppression of the first order sea clutter in shipborne HFSWR. Moreover, interpolation in spatial domain is proposed to retrieve signal for DPCA processing in consideration of the vibration of the platform motion. Simulation results show that the method can remarkably attenuate the first order sea clutter when the platform velocity slightly vibrates over the theoretical value. Furthermore DPCA processing with interpolation in temporal domain is given based on the space-time equivalence of signal, which dramatically ease the restriction on the platform velocity required by interpolation in spatial domain. Theoretical analysis shows that DPCA with interpolation in temporal domain can detect target if only the platform moves at constant velocity. It can be更多还原