A new method for measuring the time-of-flight in fast laser range finding

A new method for measuring the time -of- flight in fast laser range findingRaimo Ahola, Risto MyllylaUniversity of Oulu, Department of Electrical EngineeringSF -90570 Oulu, FinlandAbstractA new method for measuring the flight time in high speed, high resolution ranging applica-tions is presented. The detailed theoretical consideration of the method shows that themethod is well suited to these applications. Examples of practical constructions and theirperformance show that the method can be put into practice with a very small number ofcomponents with good results.IntroductionTime -of- flight laser ranging is inherently a fast method for distance measurement. In prac-tice the speed, resolution and accuracy of the measurement are very much dependent on the prin-ciple and construction of the unit used to measure the transit time of a light pulse. Fasthigh resolution applications for the time -of- flight method are numerous, especially in industry.In many industrial applications, the ranges to be measured are short (< 10 m), but theresolution and the speed of the measurement needed are usually very high1 -5