高速运动目标的频域合成带宽方法

Frequency Domain Synthetic Bandwidth Approach for High Speed Moving Target

为了利用线性调频步进雷达获得高速运动目标的高分辨距离像,提出了基于高速运动模型的频域合成带宽方法.该方法根据运动目标雷达回波的精确模型建立运动补偿因子,并在时域将回波信号与频域频谱搬移的误差频率混频,以消除频域频谱搬移误差的影响.与传统的基于低速运动模型的合成带宽法相比,所提方法对高速运动目标回波补偿后不存在子脉冲频谱的初相补偿误差和失配误差,具有更高的补偿精度.针对高速运动目标的仿真结果表明,在采用海明窗加权的情况下,与基于低速运动模型的频域合成带宽法相比,所提方法得到的距离像没有出现栅瓣且副瓣电平在-42 dB以下.

In order to utilize the linear modulated stepped frequency radar to acquire the high resolution range profile of the high speed moving target, an improved frequency domain synthetic bandwidth approach is proposed. In the approach, the motion compensation factor is established in terms of the precise echo model of the moving target, and the error of spectrum shift in the frequency domain is eliminated by mixing the echo signal and the error frequency. Compared to the traditional synthetic bandwidth approach based on the low speed moving target model, the proposed method avoids the initial-phase compensation error and unmatched error of the subpulse^s spectrum after compensating the high speed target echo, and possesses higher compensation precision. Aiming at the high speed moving target, the simulation results show that under the case that the Hamming window is used to weight the synthetic spectrum, the target range profile does not have grating lobe and the peak-to-side lobe ratio of that is-42 dB below.