Five generations of integrated electronic tachymeters

Five decades have passed since the introduction of the first integrated electronic tachymeter. Many innovative technologies in the construction of them have appeared since then. Compared to the early models, which only measured and stored direct measurements, tachymeters have become more sophisticated by means of incorporating internal microprocessor and software packages, reflector-less distance-measuring capabilities, robotic functions, image assistance, and other features, and have become multi-sensor systems. The modern tachymeter is a universal measuring platform that adapts, with its great flexibility to the application in various terrestrial surveying tasks. To better understand tachymeters and their specific characteristics, capabilities, and development, it is necessary to group them by generations. The authors of this paper have recognized five tachymeter generations with the purpose of marking the main technological advances in the historical development of these instruments.