针对SAR的快速1-bit极简欺骗干扰方法研究

Deceptive jamming can generate false targets with high fidelity in a SAR imagery. To improve the elusiveness and power of the jamming, elaborate modulation and wide-area coverage are required by a deceptive jammer, resulting in leaping operand and complex system, which cause high cost and low efficiency. For these reasons, this project studies a rapid and highly simplified deceptive jamming method against SAR based on 1-bit sampling and quantization theory. Firstly, a 1-bit interception method for the SAR signal is discussed to solve the roots causing problems such as high data-width and large data amount in the jamming modulation. Then, by dissecting the focusing mechanism of the false targets, a modulation template generation strategy is addressed using different accuracy for time delay and phase to reduce the computational complexity. Moreover, a highly simplified 1-bit deceptive jamming modulation method is designed employing logical operations, which accomplishes low cost and high efficiency. Furthermore, different time-varying thresholds are utilized to compensate the nonlinear distortion in the 1-bit retransmission for false targets with different scattering characteristics. Finally, the error transfer and accumulation features during the “interception-modulation-retransmission” stages in the 1-bit deceptive jamming are revealed, and an effective error feedback regulation is provided as a basis for the jammer’s parameters design. This project is aiming for achieving significant system simplification and efficiency improvement at the cost of a slight accuracy loss, which is able to provide support to low cost and miniaturization for the SAR deceptive jammer.

欺骗干扰能够在SAR中产生逼真的虚假目标。为了提高干扰的隐蔽性与威力，干扰机需要进行精细调制与广域覆盖，导致运算量剧增，系统复杂，引发高成本、低效率等问题。为此，本项目基于1-bit采样量化理论对SAR的快速极简欺骗干扰方法展开研究。首先探讨SAR信号的1-bit截获方法，解决干扰调制中数据位宽高、数据量大的问题根源。然后剖析虚假目标聚焦的深层机理，利用延时与相位异精度的调制模板生成策略降低运算复杂度。并设计基于逻辑运算的1-bit极简干扰调制方法，达到降低成本、提高效率的目的。进而针对不同散射特性的目标，采用不同的时变阈值来补偿1-bit转发中的非线性失真。最后，探索1-bit欺骗干扰“截获-调制-转发”各阶段误差传递与积累特性，提出有效的误差反馈调节方法，为干扰机的参数设计提供依据。本项目以期以微小的精度损失获取显著的系统简化与干扰效率提升，为SAR欺骗干扰机的低成本与小型化提供支撑。

本项目基于1-bit采样量化理论对SAR的快速极简欺骗干扰方法展开研究，解决了干扰机在精细调制与广域覆盖需求下面临的运算量剧增，系统复杂，引发高成本、低效率等问题。针对SAR欺骗干扰“截获-调制-转发”的不同阶段，开展的具体研究工作如下：(1)建立1-bit SAR信号模型，为1-bit截获提供理论支撑，为干扰调制中的谐波分析提供依据；(2)设计异精度的调制模板生成策略，在保障干扰性能的同时降低运算复杂度，基于FPGA设计并验证干扰调制方案有效性；(3)提出基于时变阈值的1-bit量化策略，有效补偿1-bit转发中的非线性失真。.利用1-bit量化信号，传统卷积过程中的相乘运算被转化为逻辑运算，大大简化了欺骗干扰机的硬件实现。本项目所提方法有效地保留了虚假目标的幅度信息，并保证了欺骗干扰的2维聚焦质量，能够达到与传统方法一致的干扰性能。本项目提出的1-bit欺骗干扰算法能够适用于不同的瞬时斜距差计算方案，可以用于简化不同的欺骗干扰机实现架构，具有广泛的适用性。此外，本项目研究成果表明，采用不同的量化阈值进行1-bit量化可产生不同的干扰效果，如高斯阈值能够实现欺骗与噪声联合干扰效果，单频阈值能够实现与高精度欺骗干扰相似的性能，为1-bit干扰理论体系的深化与完善提供了可行的思路，为后续的研究奠定了必要的基础。.本项目发表期刊论文12篇，其中SCI检索10篇、EI检索2篇；发表会议论文9篇，其中EI检索9篇；申请国家发明专利19项，其中已授权12项，受理/实审7项；培养博士后4人，独立指导硕士研究生7人，合作指导硕士研究生12人；获得国家自然科学基金面上项目资助2项。项目组多次参加国内外相关学术会议交流，扩大了本项目1-bit SAR成像及对抗相关领域理论与方法在学术、应用领域的认同和影响力。