Research On Pulsed Laser Rangefinder

This paper is about the research and development of the pulsed laser rangefinder. The topic source is based on the development and application of integrated laser rangefinder which ranging accuracy is ± 10m for some stabilization collimator.According to the research of domestic and international laser ranging instrument selection, ranging theory chooses to use the time of flight method, and futher compares the two theories of the time of flight method, namely, the pulse laser ranging and the continuous wave laser phase shift ranging. And the former meets the system requirements most effectively.Pulsed semiconductor laser ranging system includes three parts:laser emission system, laser receiving system and time measurement unit. In order to improve the ranging precision of single pulse laser, narrow width and high energy of the laser pulse, speedy measurement of pulse rate and the wide bandwidth of receiver are required. Emission system chooses a kind of solid laser, using BND saturated absorption fuel as the Q element, to receive light with narrow pulse width and high energy. The receiving system unit uses avalanche photodiodes, and threshold circuits are added in the amplifying circuit to output accurate closing signal for time measurement unit. Time measurement unit uses the clock which frequency is chosen as 30MHz, and quartz resonators can achieve the precision of 5m. In theory, the paper analyzes the main sources of pulsed laser ranging error and various factors influencing the measuring accuracy of the flight time, summarizes several main methods to improve the ranging precision. Finally, the pulse semiconductor laser range finder is tested, and the experiment result proves that the measurement system meet the design requirements.