The Design Of Portable Laser Rangefinder

With the rapid development of semi-conductor laser technology,laser's application in the field of ranging has become far more common.Nowadays,the laser range finder's development trends have become convenience,low power consumption and high precision.Main laser ranging methods are included pulsed measurement and phase measurement.This paper designs a portable laser range finder based on pulsed measurement,which ranging measurement has expanded to 800 meters and the accuracy is 0.1 meters.Also,the final product meets the performance index in the actual measurement.This paper introduces the research background and significance of this task at first,then discusses the development situation in the domestic and international.Several principles of laser ranging are introduced in this paper.In the part of hardware circuit,a suitable laser diode is selected as the laser emission source by analyzing the transmission characteristics of the laser in the atmosphere.The boosted circuit is designed to generate high voltage and drive the laser diode emitting circuit on the basis of chopping boost principle.The PIN photodiode is chosen as the photo detector.The bias circuit of the photodiode is introduced,and the photocurrent is converted into the voltage signal through the two-stage amplifying circuit.In this paper,a new timing measurement method based on TDC-GP21 is used to reduce the difficulty of the circuit design and ensure the accuracy of the timing measurement at the same time.Also,the working principle of TDC chip and its calibration principle is introduced briefly here.At last,the working principle of the acceleration sensor and the way converting to the measurement of obliquity through acceleration is illuminated.What's more,the design procedures of the rest peripheral circuits are given,and the working principle is analyzed.In the software part,the corresponding software workflow is given for each module in the whole system.The error analysis in the actual measurement process is analyzed and compared.A new algorithm is proposed and programmed which has achieved good performance in the practice.At the end of the paper,a summary of the existing research result is given,and some deficiencies which appear in the result are analyzed.Finally,the future improvement and research direction are pointed out.