Study Of New Phase Laser Range Finder

Laser has many advantages, such as monochromatic, good orientation, high bright etc., which lead to the laser finder to be the appropriate equipment for the high accuracy distance measurement., Rapid and drastic changes are taking place in the filed of laser ranging, and it extensively used in the military and the civil field. By far up to now, it tends to eye-safe, and small size, high reliability, integrate with other optic instrument.In this paper, the main work is summarized as follows:(1) The background of the project was introduced, the principle of the phased-shift rangefinder is introduced in detail. And this paper gives an overview of key technique of phase laser ranging. Which is included the choice of modulation frequencies and the method of measurement of phase.(2) Using PIN photo diode, low noise CFA (Current Feedback Amplifier) and SAW (Surface Acoustic Wave) filter implement a receiving system of phase laser rang finder. The major noises of PIN photo diode are analyzed and a preamplifier circuit with low noise is designed which raise the SNR (signal to noise ratio) effectively. To reduce insert loss of the SAW filter, a matching net is designed. The circuit self-excited owing to high frequency operating is also taken into account. Some measure was implemented. Experiment's results indicate that the receiving circuit has small volume and high reliability with good capability.(3) A new signal generation method for phase laser ranging finder is proposed based on DDS (direct digital synthesizer) technology of FPGA. Accomplished the design of program and carried on experiment. The results of experiments proved that the SNR is more than 60dB.Compared with other methods, it has higher stable frequency, smaller size and lower power consume.(4) A practical design of new phase laser range finder based on (1) and (3) was introduced. The diagram of the instrument was given.This paper presents a new phase laser range finder, which is small size, high reliability, low power consume to be used in a practically work. In addition, if make some improvement, this instrument was expected to integrate easily with other optic instrument.