Angular control quality in survey

This paper dealt with the quality control of angular measurements which are a critical element in the construction of subway tunnels and similar projects, in which it is necessary to maintain precise alignments and points coordinates on an open polygonal without controlled closing and with direct application on guiding digging machines and tunnel construction. Thus, methods and procedures to control the precision and accuracy of these measures were studied. Performance of several total stations, in several campaigns were analysed; a quadrilateral and their angles were measured and adjusted to serve as a standard, to allow not only the assessment of the precision, but also the accuracy of the equipment. As a result, proposals, procedures and criteria were presented to be incorporated into standard quality control measurement of angles.