Research On Key Technology Of Phase-Shift Semiconductor Laser Range Finding

The laser range finder is a precision measuring technology, which is widely used in the military field and the civil field in which high accuracy is needed.In this paper, the major tasks are as follows:Various methods of phase detecting are analyzed. The principle of phase laser range finder is discussed in detail. A practical range finder system is designed. The system is divided into three parts based on their functions. They are sending systems, receiving system, phase testing and signals candling system.The phase-locked loop with negative feedback to realize the automatic frequency track is designed, and the modulating technology of semiconductor laser ranging is studied. The study selects the direct modulation method to carry on the luminous power of laser's projection.The receiving system is designed based on the MULTISIM and PROTEL software about circuit designing, using PIN as the detecting device which can convert the modulated signal to electric signal successfully. The amplifier and filter circuit is designed correctly also. And the receiving system is realized.An Analog Multiplier is used as mixer and the high isolation of the mixer between two input signals is obtained to remove the interference between two different frequency signals. It uses the multi-cyclical synchronization phase demodulation to realize the fast and high accuracy of automatic digit range finding technology.The result is analyzed about noise and error, and the precision of range finding is improved. The ideality results of system and the practical experimental results are discussed. As a result, the method using phase laser range finding to detect distance is feasible.