The Design Of High Precision Pulsed Laser Ranging System

Laser range finder has the advantages of far measuring range, fast speed, high precision and strong anti-interference ability, so it has been widely used in the fields of Surveying and Mapping, Construction, Transportation, Aerospace and Industry. The laser ranging is divided into two kinds of pulse method and phase method. In this paper, through the study of laser ranging, aims to provide a low cost, multifunctional, wireless laser range finder.This paper firstly introduces the principle of laser range finder, choose the pulse method as the measurement method of the system, and then puts forward the overall design scheme of the system, the laser ranging system is consists of laser emission circuit, laser pulse receiving and processing circuit, the time interval measurement circuit,the main control circuit based on TMS320F2812, Zigbee wireless transceiver module and software,to achieve distance, area, volume and height measurement of the target.The laser emission circuit adopts a small power semiconductor laser diode that is safe to eye as the laser of system, using the D trigger design laser drive circuit. Laser pulse receiving and processing circuit selects PIN photodiode as photodetector, designed pre current to voltage conversion circuit to realize the conversion of the photodiode current, according to the characteristics of signal in low SNR, designed low noise amplification circuit and filter circuit makes the SNR is improved greatly, and identify the began time of laser pulse and the return time of the echo pulse accurately. In the time interval measurement part, using the time to digit technology design a high-precision timing circuit for accurate measurement of the laser pulse time of flight.The main control circuit is mainly consist of TMS320F2812 and its peripheral circuit, it is responsible for scanning function selection keys, control the laser emission circuit generates laser pulse, control timing circuit measure the flight time of laser, calculating and processing the data, control the serial port to send the measurement results and the liquid crystal display unit to display the measurement results. Zigbee wireless transceiver module realizes the wireless transmission of measurement data, the software system includes the measurement procedure, wireless transceiver module program and the upper computer data receiving system, the upper computer software is designed by C# language, enabling users to view data and remote operation.Finally, the pulse laser range system has been tested and put forward a data fitting algorithm that can reduce the measurement error, the measurement results show that the system has basically met the design requirements, has the advantages of low cost, convenient use, high precision and good application prospect.