Fpga-based Computing, Portable Laser Rangefinder

In the first chapter of this paper, the theory of laser range finder is introduced; the technological disadvantages are discussed. In the following chapter, a novel laser ranging method based on phase ranging technology is proposed. By using FPGA and FFT operation,phase can be obtained. Various technical measures are adopted to minimize the interference from the environment .and the requirement of components' performance is decreased which redues the cost while not significantly increase the system complexity. The proposed system can work under hostile conditions such as high temperature and strong EMI.The hardware frame and the methods to calculating the power parameters are mainly discussed in this thesis.With regard to the hardware design,we use the 89C51 to control the ADwhich can sample the echo signal .The communication part of this system provides the interface to the user,and it can receive the upper's commands, set parameters and transmit the information.With regard to the software design, we use the Fast Fourier Transform Algorithm to analyse the harmonic of the signal ; also we analyse the method of calculating the distance.The feasibility of the laser ranging scheme is proved in the paper.Theoretically, The ranging precisi on in the order of millimeter is obtained. When various technical measures are adopted to minimize the interference from the environment. The method is novelty,and the influence from environment is tittle.It can be used to measure short distance(usually less than 20m) under hostile conditions.The results prove that the scheme is feasible.