Time Expansion of Pulse Echo Signal Implemented for Laser Ranging System With High Precision

This article proposes a pulse laser ranging method based on the correlated sampling time expansion, which enhances the precision of pulse laser ranging. We introduced an additional sampling pulse signal, which has a certain frequency difference from the transmission signal. By utilizing the principle of correlation sampling, the sampling signal is used to sample the pulse echo signal, resulting in temporal expansion of the echo delay. The actual distance is then calculated based on the expansion factor. This method overcomes the limitations of traditional time-of-flight (TOF) methods that rely on time-to-digital converter (TDC) chip timing, substantially reducing timing errors. Our approach is implemented using a field-programmable gate array (FPGA), a sampling unit, and a set of laser transmission and reception devices, resulting in a low-cost system. Experimental results demonstrate that our method achieves high-precision ranging and effectively reduces errors in TOF ranging, with each measurement error reduced to the millimeter level or even lower. Our proposed method holds great promise in the field of high-precision ranging.