调频连续波激光雷达距离-多普勒解耦新方法

调频连续波激光雷达探测运动目标时,通常采用二维傅里叶变换解耦合方法.当探测高速运动目标时,由于目标移动导致不同调频周期的中频信号频谱峰值不在同一距离单元,用二维傅里叶变换法进行解耦将产生速度模糊.新的解耦方法通过对多个周期的中频信号频谱峰值位置进行直线拟合,获得目标径向速度估计值.利用速度估计值构建多普勒补偿信号,并与原中频信号相乘.补偿后的中频信号频谱峰值在同一距离单元内.将补偿后的中频信号用二维傅里叶变换法获得的径向速度与之前的速度估计值相加,得到最终的目标径向速度.仿真结果说明新方法在获得较高测距、测速精度的同时,可以有效提高调频连续波激光雷达的无模糊速度.

New range-Doppler decoupling method for FMCW ladar

FMCW(frequency modulation continues wave) ladar could detect moving target.It often uses 2-dimension FFT method to decouple range and doppler frequency.When detecting high speed target,different chirp period spectrum peaks are not in the same range bin,and using 2-dimension FFT method would acquire a fuzzy speed.In the new decoupling method,one fitting line was acquired from serial period’s spectrum peaks at first,and an estimated speed was achieved.Then a Doppler compensation signal based on the estimated speed was given and plus with the original IF signal.It makes the spectrum peaks of serial periods compensated IF signal are in the same range bin.By using 2-dimension FFT method on compensated IF signal,a compensated speed was achieved.And the target speed could be the sum of compensated speed and estimated speed.Simulation results indicate that the new range-Doppler decoupling method could effectively extend no fuzzy velocity of FMCW ladar,and achieve high precision of target range and velocity at the same time.