The Influence of Temperature on Gyrotheodolite Measurements

Abstract This master's thesis focuses on studying the influence of different ambient and internal temperatures on the measurement accuracy of the Gyromat 5000 gyrotheodolite. The study's primary objective was to determine the expected measurement results when performing gyroscopic measurements at varying air temperatures, to investigate the relationship between air temperature and the internal temperature of the instrument, and to examine how these factors affect the measured values. The work is based on raw data collected during a seventeen-hour continuous measurement campaign, which was thoroughly analysed through a visual and statistical correlation study using scatter plots of essential factors, such as ambient temperature, the instrument's internal temperature, and the torsion tape zero position. In the theoretical part, an attempt was made to explore and precisely describe the knowledge related to the principles of the suspended gyroscope operation. The results of scholars dealing with issues related to practical gyroscopic measurements, the development of algorithms related to the mechanics of suspended gyroscopes, and the problem of geodetic refraction and its influence on precise geodetic measurements of horizontal angles were also accessed and presented. The research part focused on conducting a measurement campaign following the principles applicable to the performance of precise geodetic measurements in variable field conditions, considering such factors as the need for perfect stabilisation of the instrument or the most accurate isolation of the station and target point from the extreme direct influence of external factors, such as direct sunlight or a strong gust of wind. The results indicate that the ambient and the instrument's internal temperatures significantly and systematically influence the measured azimuth values. The analyses confirmed that sudden temperature drifts can change the measured azimuth value. The conclusion presents the most critical observations gathered during fieldwork and while analysing the raw data.