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相控阵雷达同时多波束成像可广泛应用于环境检测、弹载平台定位等场合.文中根据相控阵原理设计了同时多波束天线方向图,推导了方向图各波束指向、波束宽度与阵列结构参数的关系.在对各波束回波信号特性分析的基础上,得到了宽带条件下不同应用环境时多普勒谱不混叠条件,推导了多波束成像模式对脉冲重复频率的约束条件.在合理参数的情况下,获得总的回波信号并通过对应于各波束的频域滤波器分离各波束回波信号,利用方位向上的非线性调频变标算法分别进行SAR成像,并对各波束成像性能进行了分析.仿真结果表明,本文模式可实现同时多波束成像,当平台速度与阵列法线垂直时,SAR斜视角不大的情况下,各波束SAR图像方位分辨率基本保持不变;当平台速度与阵列法线重合时,各波束SAR成像方位分辨率随波束指向靠近法线分辨率急剧下降,但远离法线又会带来更严重的孔径渡越效应,因此应合理确定SAR成像各波束指向.
At the same time, the multi-beam imaging of phased array radar can be widely used in the environment detection, the positioning of the launch platform etc. According to the principle of phased array, the directional pattern of multi-beam antenna is designed and the beam directions, beam width and array structure The relationship between the parameters of the beam echo.Based on the analysis of the characteristics of each beam echo signal, the Doppler spectral non-aliasing conditions under different broadband environments are obtained, and the constraints of the multi-beam imaging mode on the pulse repetition frequency are deduced. Reasonable parameters, the total echo signal is obtained and each beam echo signal is separated by a frequency-domain filter corresponding to each beam, SAR imaging is performed by using an up-direction non-linear frequency modulation algorithm respectively, and each beam is imaged The simulation results show that this model can realize simultaneous multi-beam imaging. When the platform velocity is perpendicular to the array normal, the azimuth resolution of each beam remains almost unchanged under the condition of small SAR oblique angle. When When the velocity of the platform coincides with the normal of the array, the azimuth resolution of each beam SAR sharply decreases with the beam pointing near the normal resolution, but far away from the normal Lead to more serious effects transit aperture, and should therefore be reasonably determined SAR imaging point of each beam.