The Research And Design Of A Hand-held Phase Laser Ranger

Laser range finder is widely used in our daily life. It can replace the cumbersome manual operation and measure the untouchable corner easily. It is a kind of effective and convenient measuring tool. Laser has the characteristics of strong directivity, good monochromaticity and coherence which make it the ideal light of the new generation of range finder. Laser modulated with waves of different frequencies is sent and received. Measure the phase difference between the sent signal and the received signal and get the distance value through calculation.As the development of the contemporary electronics, the measurement of the phase can be very precise. APD(Avalanche Photo Diode) can receive the laser signal sensitively and we can process a large number of data so as to make out measurement precise through just one tiny Single Chip Microcomputer. Weak signal detection technology is introduced to recover the Signal in noise.Through the analysis of existing laser ranging technologies as well as the comparison of the performance of such different technologies, phase laser ranging method is proposed. Two significant technologys-difference frequency method and multiple rules technology are employed in the paper. My treatise has simulated two weak-signal-detection algorithms by Matlab.Innovative points:(1) Introduce two weak signal detection algorithms in our laser range finder system to improve the precision of the measurement.(2) Measure the Internal optical path and External optical path separately to eliminate the initial phase.(3) Frequency of sampling exactly synchronizes with the frequency of the input frequency.