基于回波信号插值重建的峰值判别技术

在脉冲式激光测距技术中,测量距离和目标反射特性变化等因素会引起微弱回波信号的峰值判别误差,造成激光飞行时间的测量误差,峰值判别误差是影响激光测距精度的主要因素之一.针对激光测距中微弱回波信号不规则引起的峰值判断精度低的难题,采用FPGA控制采样电路对回波信号进行高频采样,通过软件对采样数据进行插值重建,根据重建图形判断出回波信号的峰值点位置作为计数停止点,有效提高了回波信号峰值判别精度.实验证明:采用该项技术的激光测距机能够达到0.1 m测距精度.

Peak recognition technology based on linear-interpolation rebuilding method of echo signal

One of the main disadvantage of the pulsed laser rangefinder is the low precision of peak recognition, affected mainly by the faint irregular echo signal. Echo signals of the pulsed laser rangefinder change greatly for various operating ranges and target reflection characteristics, which induces measurement error of laser flying time and couldn't be treated perfectly by the traditional peak recognition circuit. Aiming at the problem of low precision for the pulsed laser ranging, a novel peak recognition method of the echo signal was introduced. In the proposed method, the echo signal was sampled by the high frequency sampling circuit controlled by FPGA. Through the interpolation program, the echo signal was rebuilt to recognize the position of peak point, which was used as the stop point of timing system. This method would lead to higher precision peak recognition finally. The experimental results prove that the linear-interpolation method of echo signal can improve the laser ranging accuracy to 0.1 m.