The Application Of DSP Technology In Laser Range Finder

Since Dr. T.H.Maiman of U.S.A. made the first laser instrument in the world in 1960, the laser's excellent monochromatic, directionality and high light characteristic cause the concerns from all walks of life. Technology of the laser range finder is a kind of comparatively extensive laser technology at present. Comparing with general method of range finder, it has a lot of advantages, such as easy to operate, available with the day and night, high precision, etc. The laser range finder was divided into two kinds of the pulse type and continuous type at present. Pulse type laser range finder is used widely for its large measurement range, precision high and easy to use (without cooperative goal). Comparing with pulse type, the continuous type laser range finder arouses the attention from people again with the development of technology of the laser instrument in recent years. In the civil field, the continuous type laser range finder is especially expected in some no real-time character systems, such as earth measurement, products error-detecting, road surface precision measure, etc.Miniaturized, intelligent, high accuracy, safe to the human eye is the developing direction of laser range finder, but present laser range finder generally has a lot of shortcomings, such as more components and parts, weight is heavier, the consumption is relatively high, flexibility is not enough, weak anti-interference ability. So it is unfavorable to realizing the integration and miniaturization of the laser range finder.Aiming at the shortcomings of the laser range finder at present, this thesis puts forward a kind of new thought, applying digital signal processing technology to the continuous type laser range finder. The detail way is to utilize DDS technology produce sine signal to modulate laser instrument and to utilize FFT technology and digital correlation technology detect the phase.The laser range finder with digital signal processing technology is not only merely overcoming the shortcomings provided above, but also holding the following advantages: First is the frequency of modulating can be changed through the method of the software. Comparing with traditional several sets of circuits, it simplifies the design greatly and improves the convenience; Second is it solves theproblem that frequency is unstably and the phase is shaking in the laser range finder by using DDS technology. It makes the stability of the range finder higher; Third is not only it has high precision, but also it has space of promotion on the precision by using FFT technology and digital correlation technology detect the phase with the constant development of the micro-electronics technique; Fourth is it uses DSP IC deal with the signal to improve real-time character.