微波光子相控阵的技术分析与展望

该文探讨了相控阵雷达的发展需求,提出了基于微波光子技术的新型相控阵的架构形式和技术路线。针对其工程实现,凝练了当前所面临的主要科学问题和重大技术挑战,并对未来的研究工作和该领域的发展进行了展望。      

基于去调频接收技术的微波光子双波段线性调频连续波雷达

该文提出一种基于光子辅助去调频接收技术的双波段线性调频连续波雷达方案,该双波段雷达接收机基于平行架构光子混频器,能够利用同一套硬件设备同时接收双波段雷达的回波信号。接收机中使用一个双偏振正交相移键控(DP-QPSK)调制器,工作中将双波段雷达的两组参考信号和回波信号通过DP-QPSK调制器调制到正交偏振的光载波上,调制后的双带光回波和参考信号经过放大和滤波后,输入到偏振解复用相干接收机中进行光子辅助去调频处理。在发射机端,对于具有更高频率和带宽的发射信号,采用包含延时功能的光子倍频信号产生技术,产生参考信号与发射信号的同时,将发射信号延时,使得在接收机端对相同距离目标的双带回波信号去调频得到的中频信号可在频域分离。实验中通过逆合成孔径雷达成像实验评估了该双波段雷达系统的性能,该双波段雷达系统工作在C波段和Ku波段,发射信号带宽分别为1 GHz和2 GHz,接收机模拟-数字转换器的采样率为100 MSa/s。实验结果证明微波光子技术能为双波段线性调频连续波雷达提供有效的实现方案。      

雷达发射机浮动板调制器与故障检测电路的设计

提出了一种改进的浮动板调制器和对正负偏电压的故障检测电路,利用MOSFET寄生电容特性,通过固定脉宽窄脉冲控制调制脉宽,通过增加负偏MOSFET提高输出负偏电压。对故障检测电路进行仿真实验,通过模拟故障,验证故障检测报警信号发生时间均在微秒级别。完成样机的搭建,利用多重方式解决高压绝缘问题,并对其加电进行试验验证,分析实验波形,证明此电路满足设计要求并且具有可行性。     

双频雷达动目标近场定位算法

利用双频雷达对运动目标进行定位现已受到广泛关注。虽然已有文献对双频雷达进行了一些研究，但这些方法都是基于远场假设的。因此，提出了一种简单的基于菲涅耳模型的利用单站双频雷达进行近场定位的新方法。有别于现有方法需要联合搜索或者需要复杂的矩阵运算，该方法仅使用简单的代数运算就能提供闭式解，可直接应用于低成本的嵌入式设备。此外，推导了单站双频雷达定位问题的克拉美罗下界（CRLB），为性能评估提供了基准。仿真结果验证了该方法的有效性。     

雷达目标辨识网络的对抗性样本分析

为了验证雷达目标辨识网络存在风险,提升基于辨识网络的雷达目标辨识效果,文中研究了不同雷达目标辨识网络的对抗性样本。针对雷达目标辨识网络中的卷积神经网络和分解卷积神经网络,建立对抗性样本生成模型,按照该模型生成对抗性样本,并对生成的结果进行分析总结。实测数据处理结果表明,雷达目标辨识网络存在潜在风险。     

Joint Monitoring of Ground and Sky for Cereal Crops Based on Scatterometer Measurement and ASAR Images

The joint monitoring of the ground and sky for cereal crops based on microwave data has become a popular method for researches on earth surface objects. Focused on the sensitivity of backscatter from the scatterometer measurement and advanced synthetic aperture radar (ASAR) images to cereal parameters of rice, nine acquisitions, including rice parameters related eco-physiological variables and scattering coefficients, have been carried over the paddy field corresponding to rice growth stages. This paper analyzes the relationship between the corresponding backscatter to the cereal parameters based on the measurement at the interesting bands, polarizations, and incidence angels. Further, a modified water cloud model is built based on the ground measurement and advanced integrated equation model (AIEM), and then cereal parameters from ASAR images are retrieved and verified. The research results show that the sensitivity of backscatter to cereals from the sensor of the radar scatterometer could be helpful to build the retrieve model for synthetic aperture radar (SAR) images, which can achieve the scientific goals of the joint monitoring of ground and sky for cereal crops.     

Separable transmit beampattern design for MIMO radars with planar colocated antennas

Multiple-input multiple-output (MIMO) radar transmit beampattern design for one-dimensional arrays has been widely studied in literatures. In this paper, transmit beampattern design is considered for two-dimensional (2D) arrays. As the size of the array is increased, the computational complexity and time for pattern optimization are increased drastically. To overcome these problems, we introduced the conditions upon which the 2D beampattern design for uniform rectangular arrays (URA) can be achieved via the product of two perpendicular transmit beampatterns of uniform linear arrays (ULA). The transmit beampattern design is accomplished under special characteristics such as minimum integrated sidelobe level or special 3 dB beamwidth in azimuth and elevation with much lower computation time.     

On the Smith normal form of a skew‐symmetric d‐optimal design of order

We show that the Smith normal form of a skew‐symmetric D ‐optimal design of order is determined by its order. Furthermore, we show that the Smith normal form of such a design can be written explicitly in terms of the order , thereby proving a recent conjecture of Armario. We apply our result to show that certain D ‐optimal designs of order are not equivalent to any skew‐symmetric D ‐optimal design. We also provide a correction to a result in the literature on the Smith normal form of D ‐optimal designs.     

基于Nef的组网雷达包络三维可视化研究

提出了采用基于CGAL库定义的Nef多面体数据结构,并结合Nef多面体之间的三维布尔操作来解决组网雷达探测范围相互重叠的雷达包络可视化问题。试验测试结果表明,每组试验样本求交后的三角网格正常,可视化效果好,满足项目应用需求。     

TNR型调频广播外辐射源雷达探测实验

针对信号带宽时变、目标RCS闪烁造成单调频广播外辐射源雷达探测性能下降的问题,研究了一种TNR型外辐射源雷达的试验方案,并开展了外场试验验证。首先,阐述了TNR型外辐射源雷达的定位原理。然后,基于外辐射源雷达探测原理和广播信号的特性,提出了TNR调频广播外辐射源雷达探测系统中多个辐射源的筛选原则。最后,构建试验系统并给出探测试验结果。结果表明,TNR型系统方案可以大幅度提高调频广播外辐射源雷达的发现概率和定位精度等性能。