一种改进的FMCW雷达线性调频序列波形

A Modified Chirp Sequence Waveform for FMCW Radar

采用线性调频序列波形(chirp sequence waveform)的调频连续波(Frequency Modulated Continuous Wave,FMCW)雷达在汽车防撞探测等领域得到了广泛应用.针对该体制雷达的多目标解多普勒模糊问题,本文对线性调频序列波形进行了改进,在所有偶数序号扫频周期前插入了延时.改进后的波形可分解为两个扫频重复频率相同的传统调频序列,一个由奇数序号的扫频周期构成,另一个由偶数序号的扫频周期构成.波形中的延时会使两个序列对应的差频信号组之间产生相位差,利用此相位差信息可以解多普勒模糊.仿真结果验证了改进波形及其信号处理方法的多目标环境适应性和抗噪性.

FMCW（ Frequency Modulated Continuous Wave）radar with chirp sequence waveform is widely used in automotive applications. To resolve Doppler ambiguities in multi-target environment, we modify the classical chirp sequence waveform by adding a period of time delay before each chirp with even sequence number. The modified waveform is essen- tially a combination of two classical chirp sequences, one is composed of all the chirps with even sequence numbers, and the other one is composed of all the chirps with odd sequence numbers. The time delays in the modified waveform generate a phase difference between two beat signal groups corresponding to the two chirp sequences. Doppler ambiguities are resolved by the phase difference. Theoretical analysis and simulation results verify the effectiveness of the modified waveform.