Research on Signal Receiving System of Phase Laser Range Finder
|School||Harbin Institute of Technology|
|Course||Instrument Science and Technology|
|Keywords||Laser range finder Avalanche photodiode Phase Difference Measurement DSP|
The laser range-finding technique is a widely used technique for distance measurement at present, which manifests the merit of high accuracy, non-contact operation, diurnal available server, and reliable performance. Along with the rapid development of technology on fields such as semiconductor laser, integrated circuit, digital signal processing, precision machinery, which promote the laser range finder towards high precision, miniaturization, and digitization, the laser range-finding technique has been widely used on geodesy, manufacturing industry and military equipment. This paper introduces the research result on signal receiving system of phase laser range finder. The receiving circuit system is designed in the paper, realizing the integration of modules performing different functions, which include the echo signal receiving and processing circuit, system control signal generation and data acquisition and processing system etc.This paper first compares and analyzes several common range-finding principles and characteristics in the field of laser range-finding techniques, and puts forward the general scheme of phase laser range-finding by the difference frequency phase measurement technique; Then, it introduces and analyzes the operating principle and features of avalanche photodetection diode, and expounds the relationship between measurement range of receiving system and receiving optical power. It also presents the realization of sinusoidal modulation wave generation circuit with direct digital synthesizer techonology, and completes the front-end design of signal receiving circuit, incluing high bias voltage generation circuit of APD, echo signal amplification circuit, filter network, frequency mixing and signal conditioning circuit etc.; Finally, it has been designed that signal conditioning and system control circuit based on DSP TMS320F2812 combined with external double channel high-speed analog to digital conversion circuit etc. The circuit debugging and simulation experiment of the algorithm for phase difference measurement has been carried on. The results demonstrate that the algorithm based on windowed FFT for the difference frequency phase measurement could satisfy the requirements of system. The works of this paper have provided the hardware platform and theoretical basis for the subsequent design work of complete machine system.