Laser Range Finding Based on Correlation Method

The purpose of the paper is to present a new laser diode range finding method. The system belongs to the category of flight time measurement. The optical power of the laser diode beam is modulated and then both emitted and returned signals are compared in order to obtain the delay or distance information. The new method is an estimation of the distance by correlation computation. The main advantages of this method are presented by simulation studies showing the robustness of the method towards noise and coupling phenomena. Then a prototype is presented associating the optical head and a simple RF board producing the signal modulating the laser beam. This signal is itself frequency modulated by a sine wave. The sampling process is performed by a digital scope and correlation computation is performed by a PC computer. The main application concerns indoor robotics.