Research And Design Of High Precision Laser Range Finder Based On Phase Method

The application of laser ranging technology is becoming more and more extensive with the continuous improvement of intelligent requirements of various industries.However,compared with foreign laser ranging products,domestic laser ranging products still have the defects of low ranging accuracy and low performance.In view of the above defects,the thesis combined with the advantages of the phase method of laser ranging,and proposed a design idea of laser ranging based on PLL signal source.The key technologies needed in the phase-method laser rangefinder are analyzed and discussed based on the product technical indicators.Then the design and analysis of the multi-group frequency for ranging are carried out.The error generated by the commonly used phase discrimination method at the same SNR is simulated with the simulation results are analyzed.Finally,the design select the full phase FFT digital phase discrimination method as the phase discrimination method.Then the overall design scheme is proposed.STM32F407 is designed as the main controller,which is divided into signal generation unit,laser modulation transmitting unit,APD photoelectric receiving unit and serial port unit responsible for debugging communication with serial port according to the functional modules.The generation of PLL high frequency signal and the implementation of phase detection algorithm are mainly analyzed in the software design with the analysis results verified.Finally,the system test platform was built,and the hardware module of the system was functionally verified by using high-performance oscilloscope.Meanwhile,the entire prototype was tested and the error analysis of the test results was completed.The test results show that the designed laser rangefinder can meet the requirements of ranging accuracy and range of1 mm,which proves that the designed laser rangefinder can meet the requirements of the system design index.The laser range finder designed in the thesis adopts PLL technology to realize laser modulation frequency higher than 150 MHz,and the actual laser ranging accuracy is 1 mm.