基于脉组间频率步进的合成超宽带距离像及速度分析

 对脉组间频率步进信号进行信号处理可直接获得合成超宽带(UWB)距离像及目标速度信息,但由于多普勒色散引入的快速傅里叶变换(FFT)输出失配误差和距离多普勒耦合,导致距离像的失真。介绍消除多普勒色散的影响的方法,分析且补偿距离多普勒耦合对距离像的影响,进一步讨论由测速误差产生的补偿量化误差对距离像的影响,并推导由此导致的距离走动公式。提出的迭代二分逼近法使速度分辨提高 N 倍( N 为脉组个数),从而得到目标真实高分辨距离像。仿真实验结果表明多普勒色散得到消除且 N 的选取更加灵活。

Analysis of Synthetical Ultra-wideband Range Profile and Velocity Based on Stepped Frequency During Pulse Trains

The synthetical ultra-wideband (UWB) range profile and velocity information of a target can be obtained directly via the signal processing of a signal, i.e., via the waveform of stepped frequency during pulse trains. However, mismatch error of fast Fourier transform (FFT) output introduced by Doppler dispersion and range-Doppler coupling often results in serious distortion of the range profile. This article introduces a method of eliminating the effect of Doppler dispersion on range profile, analyzes the influence of the coupling between range and Doppler on range profile and compensates the influence. The article then proceeds from discussing the impact on range profile to the existence of quantified compensation errors caused by the error in calculating velocity, and derives an equation to estimate the shift of range profile brought by the errors of quantified compensation. A technique by the name of iterative and dimidiate approach is proposed to improve the N resolution of the calculated target velocity (where N denotes the number of pulse trains). Therefore, the proposed approach can finally yield true target high resolution range profile. The simulation results show that Doppler dispersion is eliminated and the restriction of N is relieved.