星载雷达杂波多普勒特性分析

Characteristic analysis of clutter Doppler frequency for spaceborne radar

针对星载雷达杂波的多普勒特性,提出了在某一距离处的多普勒模糊次数的数学模型,并从三维角度对多普勒频率进行了理论分析与仿真.在杂波角度-多普勒频率二维数学模型的基础上对多普勒模糊情况进行了具体分析,并理论分析了角度、距离等多个因素对多普勒频率的影响,最后综合考虑了地球自转及平台运动带来的两种偏航误差并推导了相应的数学模型.基于提出的模型进行了仿真实验,得到在一定多普勒模糊次数的前提下信号工作频率、脉冲重复频率的上下限,仿真结果表明:杂波多普勒随距离及角度的变化而改变,赤道轨道下地球自转带来的影响较小.

In order to study the Doppler frequency of spaceborne radar clutter,the mathematical model of Doppler ambiguity number was presented at a certain range and the clutter Doppler frequency characteristics were analyzed and simulated in three dimension. Based on the two-dimensional mathematical model between Doppler frequency and cone angle,Doppler ambiguity of the clutter was analyzed. Then,the theoretical analysis of the influence of angle,range and other factors on the Doppler frequency was carried out.Two kinds of crab errors caused by the rotation of the earth and the motion of the platform were taken into account and the mathematical models were modified accordingly. Based on the proposed models,the upper and lower limits of the signal operating frequency and pulse repetition frequency(PRF) were obtained on the premise of a certain number of Doppler ambiguous.Meanwhile,the simulation results show that the Doppler frequency of clutter varies with the range and angle and the effect of the earth′s rotation under the equatorial orbit is minor.