Long distance precision measurement with double modulation laser

摘要

A new laser sensor for long distance measurement with high accuracy is proposed in this paper. A stable double modulation laser in the sensor combines the pulse modulation with the phase modulation in single time-of-flight or distance measurement. The double modulation method can be used to solve two problems. The first is the measuring range and the measuring accuracy, the second is the response speed and the measuring accuracy, which are the possible keys to advance the measuring capabilities. The measuring accuracy can be improved by the phase-based modulation. Meanwhile, the measuring range can be extended to several kilometers due to the introduction of pulse features, which can also be used to solve the multiple-solution problem in the phase modulation system. A field programmable gate array is introduced into the demodulation part to acquire the distance information. Based on the measuring uncertainty analysis the accuracy of the distance sensor is discussed.