Study On The Algorithm Of Laser Ranging System Based On FPGA

With the continuous development of science and technology, the requirement of the ranging accuracy is getting higher and higher in the modern society, Measurement methods are updated constantly. This paper studies the laser ranging system based on FPGA, the laser ranging is a kind of precise measuring technology generated in the process of the development of the laser technology. It is applied effectively in military and civilian.Two common methods of laser ranging are studied in the paper, they are pulse laser ranging and phase laser ranging, Choosing the pulse laser ranging in the end by comparing their strengths and weakness. After described the basic principles of the pulse laser ranging in detail, the whole system was divided into three parts: the laser emission module, laser receiver module, signal and data processing module. Then analysis each modules. First of all, in the laser emission module, the excitation signal generated by FPGA. This paper used the SPLLL series laser transmitter which is specially applied and developed in laser ranging and used the EL7104 as SPLLL90’s driver chip. Second, in the laser receiver module, introduced several kinds of photoelectric conversion device, after analyzed the advantages and disadvantages of them, chose the PIN photodiode which has the advantage of low noise, and then used the preamplifier circuit to filter out the noise and the amplification circuit to amplify again, then obtained the termination signal of the counter by the high voltage comparator. At the last, in the signal and data processing module, we analyzed the error sources of the time interval measurement and introduced the algorithms for reduce time interval measurement error in detail, combining with the actual demand of the system, the subject used FPGA as the main platform of time interval measurement and used the delay line interpolation method to measure time.This paper mainly analysised the signal and data processing of the pulse laser ranging system in detail, and used the PLL of FPGA to redouble the system clock, in order to improve the measurement precision. After the whole working process of the system and designed of each module are completed, we tested the performance of each module and got the relevant measurement data. The experimental results show that the desired requirements were reached.