A Digital Signal Processing System for Terrestrial Laser Range Finding Systems

Abstract

This paper presents a digital processing system for terrestrial laser range finding systems. It is mainly comprised of a commercial digital signal processor with 400 MHz. For the signal digitization, an analog-to-digital converter with a 12-bit resolution is sampled with 50 MS/s. Such a digital system architecture has several advantages: automatic gain control, coherent multi-pulse averaging, digital signal filtering, upsampling, and advanced peak detection methods. When combined with a suitable laser and detector unit, the digital system outperforms the classic analog threshold-based laser finders with regard to required laser output power, multitarget discrimination, and peak detection accuracy. The best results were achieved using a matched filter, compared to wavelet denoising techniques and classic Savitzky-Golay filtering. Finally, this system architecture allows for a small-sized, lightweight, battery-operated, and energy-efficient, class 1 eye-safe laser range finder, capable of measuring distances up to multiple km with accuracy and precision of better than 1 m to uncooperative targets.