本文提出了一种基于波束域实值处理的高阶奇异值分解(Higher-Order Singular Value Decomposition)双基地多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达测角算法。该算法与传统波束域测角算法不同,通过凸优化方法对发射和接...本文提出了一种基于波束域实值处理的高阶奇异值分解(Higher-Order Singular Value Decomposition)双基地多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达测角算法。该算法与传统波束域测角算法不同,通过凸优化方法对发射和接收波束域矩阵进行优化设计,可以灵活设置波束主瓣宽度并抑制副瓣电平,发射和接收波束的主副瓣比能够得到很大提高,从而达到提高回波信噪比的目的。相比于传统的矩阵信号模型,通过HOSVD获得的张量信号子空间可以得到更高的测角精度,所提算法对发射和接收波束矩阵的结构进行设计以构造实值张量信号模型。最后,通过建立映射关系的方法对插值误差进行补偿,仿真结果验证所提算法的有效性。展开更多
The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in...The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in a single stage setup. In this paper, we propose a new scheme to produce coherent hard X-ray FEL with two- beam based two-stage echo-enabled harmonic generation configuration. Electron beams with quite different proper- ties are separately used in each stage and a monochromator is adopted to purify the radiation from first stage for seeding the second stage. Three-dimensional start-to-end simulations have been performed with realistic parameters to show the feasibility of the proposed scheme.展开更多
文摘本文提出了一种基于波束域实值处理的高阶奇异值分解(Higher-Order Singular Value Decomposition)双基地多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达测角算法。该算法与传统波束域测角算法不同,通过凸优化方法对发射和接收波束域矩阵进行优化设计,可以灵活设置波束主瓣宽度并抑制副瓣电平,发射和接收波束的主副瓣比能够得到很大提高,从而达到提高回波信噪比的目的。相比于传统的矩阵信号模型,通过HOSVD获得的张量信号子空间可以得到更高的测角精度,所提算法对发射和接收波束矩阵的结构进行设计以构造实值张量信号模型。最后,通过建立映射关系的方法对插值误差进行补偿,仿真结果验证所提算法的有效性。
基金supported by the National Development and Reform Commission([2013]2347)National Natural Science Foundation of China(11475250)the Shanghai Natural Science Foundation(13ZR1464700)
文摘The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in a single stage setup. In this paper, we propose a new scheme to produce coherent hard X-ray FEL with two- beam based two-stage echo-enabled harmonic generation configuration. Electron beams with quite different proper- ties are separately used in each stage and a monochromator is adopted to purify the radiation from first stage for seeding the second stage. Three-dimensional start-to-end simulations have been performed with realistic parameters to show the feasibility of the proposed scheme.
