THE IMPORTANCE OF REFRACTION IN OPTICAL LEVELING

INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE “THE IMPACT OF ECONOMY, TOURISM AND BUSINESS MANAGEMENT ON THE DEVELOPMENT OF THE COUNTRY”, MAY 23, 2025 THE IMPORTANCE OF REFRACTION IN OPTICAL LEVELING Sherzod Toshpulatov1, Norkobilov Isroil Sherkul ugli2, Mamayusupov Jaloliddin Urozali ugli3 1Head of the Department at the sectoral center for retraining and professional development of pedagogical personnel under the “TIIAME” NRU 2Chief Specialist of the Department for Organizing Educational and Methodological Work at the Center for Retraining and Advanced Training of Personnel in Geodesy and Cadastre of Spatial Data Infrastructure, Cadastre Agency; 3Special Subject Teacher at the Tashkent Hydrometeorological Technical School https://doi.org/10.5281/zenodo.17395380 Annotation. This thesis analyzes the significance of refraction in the optical leveling process and its impact on measurement results. It examines the errors caused by refraction, their origins, and methods for their reduction. The study explores the potential of modern technologies, including artificial intelligence and digital modeling tools, to minimize the effects of refraction. The findings of this thesis include practical recommendations for mitigating refraction-related distortions. Keywords: optical leveling, refraction, geodetic measurements, accuracy, artificial intelligence, digital modeling, meteorological monitoring. Annotatsiya. Ushbu tezisda optik nivelirlash jarayonida refraksiyaning ahamiyati va uning o‘lchov natijalariga ta’siri tahlil qilinadi. Tadqiqotda refraksiya tufayli yuzaga keladigan xatoliklar, ularning kelib chiqish sabablari hamda ularni kamaytirish usullari o‘rganiladi. Shuningdek, refraksiya ta’sirini minimallashtirishda zamonaviy texnologiyalarning, jumladan sun’iy intellekt va raqamli modellashtirish vositalarining imkoniyatlari tahlil qilinadi. tezis natijalari refraksiya bilan bog‘liq buzilishlarni kamaytirishga qaratilgan amaliy tavsiyalarni o‘z ichiga oladi. Kalit so‘zlar: optik nivelirlash, refraksiya, geodezik o‘lchovlar, aniqlik, sun’iy intellekt, raqamli modellashtirish, meteorologik monitoring. Аннотация. В данной диссертации анализируется значение рефракции в процессе оптического нивелирования и её влияние на результаты измерений. Исследуются ошибки, вызванные рефракцией, их причины и методы их уменьшения. Особое внимание уделяется потенциалу современных технологий, включая искусственный интеллект и цифровое моделирование, для минимизации влияния рефракции. Результаты диссертации включают практические рекомендации по снижению искажений, связанных с рефракцией. Ключевые слова: оптическое нивелирование, рефракция, геодезические измерения, точность, искусственный интеллект, цифровое моделирование. Introduction. Optical leveling is one of the most widely used methods in geodesy, employed to determine elevation differences on the Earth's surface. However, during this process, the refraction of light rays in the atmosphere introduces errors that affect measurement accuracy. Refraction is one of the primary factors contributing to height determination errors. Addressing this issue plays a crucial role in improving the precision of geodetic measurements. INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE “THE IMPACT OF ECONOMY, TOURISM AND BUSINESS MANAGEMENT ON THE DEVELOPMENT OF THE COUNTRY”, MAY 23, 2025 Method. This research involves both theoretical and experimental analyses of optical leveling. A review of scientific studies conducted by various researchers on the significance of refraction in geodetic works has been carried out. According to scholars Olga Vshivkova and Igor Kalugin, geodetic production typically relies on a single methodological approach-determining refraction correction using a standard refraction coefficient. However, this method lacks sufficient accuracy. To address this issue, we are improving an angular refractometer based on a compensation method for refraction measurements. This approach implements a dual-wavelength dispersion method for determining angular refraction. 1 Findings indicate that variations in the refraction coefficient are influenced by temperature and pressure changes. To minimize the effects of refraction, it is necessary to integrate artificial intelligence and digital modeling technologies alongside traditional compensation methods. In modern scientific research, satellite data and digital simulation models are being effectively utilized for predicting the impact of refraction. Results. Analysis shows that refraction significantly affects the accuracy of optical leveling results. Changes in air temperature and frictional forces cause light rays to bend, while regional meteorological conditions alter the refractive index, leading to errors in elevation calculations. Considering the effects of wind and temperature fluctuations, it is advisable to correct measurements using specialized algorithms. A survey conducted among geodesists working in the field revealed that to minimize refraction effects, leveling should be performed in the early morning or late evening. This is because refraction intensifies when the sun is at its highest point, leading to substantial measurement errors. Additionally, a study by Lianhuan Wei, Jiaqi Zhang, Meng Ao, Shanjun Liu, and Yachun Mao analyzed the influence of meteorological parameters such as temperature, atmospheric pressure, humidity, and CO₂ on the refractive index based on field-collected meteorological data and the Rüeger equation. Furthermore, models describing the vertical gradient variations of temperature, humidity, and atmospheric pressure with respect to altitude were developed. To construct atmospheric gradient models along the optical path, the height difference between the optical path and the ground was estimated using laser scanning and precise digital elevation models. Based on this, a vertical atmospheric refraction coefficient model was proposed and applied for correcting trigonometric leveling data. 2 Thus, implementing realtime monitoring systems, developing digital refraction models, and integrating meteorological monitoring stations can help minimize refraction effects. Since refraction has a significant impact on the accuracy of optical leveling results, selecting the appropriate time for leveling based on meteorological conditions and employing specialized correction methods is crucial. Conclusion. In the future, the implementation of artificial intelligence and digital modeling technologies for the automatic compensation of refraction effects will remain a critical research direction. Additionally, integrating hydrostatic leveling, GNSS technologies, and high-precision laser scanners can further minimize refraction effects and enhance the accuracy of geodetic measurements. Future studies should focus on developing more precise refraction compensation models and designing new technologies that seamlessly integrate with real-time monitoring systems. 1 Olga Vshivkova, Igor Kalugin (Prospects for Combining a Geodetic Angle Refractometer and an Electronic Tacheometer to Improve the Accuracy of Angular Measurements) https://link.springer.com/chapter/10.1007/978-3031-43218-7_87 2 Lianhuan Wei, Jiaqi Zhang, Meng Ao, Shanjun Liu,Yachun Mao (High-Precision Trigonometric Leveling Based on Correction with Atmospheric Refraction Coefficient Model) Journal of Surveying Engineering Volume148, Issue3 https://doi.org/10.1061/(ASCE)SU.1943-5428.0000401 INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE “THE IMPACT OF ECONOMY, TOURISM AND BUSINESS MANAGEMENT ON THE DEVELOPMENT OF THE COUNTRY”, MAY 23, 2025 REFERENCES 2. Olga Vshivkova, Igor Kalugin (Prospects for Combining a Geodetic Angle Refractometer and an Electronic Tacheometer to Improve the Accuracy of Angular Measurements) https://link.springer.com/chapter/10.1007/978-3-031-43218-7_87 4. Lianhuan Wei, Jiaqi Zhang, Meng Ao, Shanjun Liu,Yachun Mao (High-Precision Trigonometric Leveling Based on Correction with Atmospheric Refraction Coefficient Model) Journal of Surveying Engineering Volume148, Issue3 https://doi.org/10.1061/(ASCE)SU.1943-5428.0000401