Designof Phase Shift Laser Rangefinder Based On Quadrature Modulation Method

Laser range finder has become a kind of regular measuring instrumentsin daily works, industrial production and scientific research in recent years. Because of its non-contact measurement and the reference traceable to the speed of light, it attracts so much attention.Even if mature products exist in market, the improvements of them are really frequently. Many companies devote themselves in researching and improving portable and industrial laser range finding technology, especially the Phase-shift laser range finder which has both considerable accuracy and working range.To improve the current phase of the laser ranging system, the defects, such as high cost , complexity , difficult to eliminate systematic errors, must be analyzed. A innovation scheme based on quadrature modulation is proposed to correct all the defects. By analyzing the structure of the system, why quadrature mixing laser ranging system is superior to traditional laser ranging system is explained in details.Subsequently, the overall system architecture and requirements are determined. After determine the whole demand, performance requirements of rangefinder some functional moduleare designed to meet the requirements of the clock , modulation , transmit , receive , filter , signal processing , as several modules the system's hardware.By comparing the some popular methods of phase measuring, the reason why Phase quadrature mixing type laser ranging system is superior to traditional laser ranging system is explained. Through compromise and comparison, a prototype is built based on the final selection of hardware and the method of phase measuring. The accuracy of the experimental system is tested. The final results confirm the accuracyof the quadrature modulation laser ranging method. Based on the experimental results and current trends of ranging products, the direction of future improvements is given.