CONCEPTUAL MODELING OF A GNSS-BASED GEODETIC CONTROL NETWORK FOR ELEVATED METRO CONSTRUCTION (CASE STUDY: TASHKENT CITY)

This study presents a conceptual modeling of a GNSS-based geodetic control network for elevated metro construction using open spatial data. A 12 km model metro corridor in Tashkent city was analyzed using SRTM digital elevation data and OpenStreetMap infrastructure layers to simulate the route alignment. Theoretical accuracy assessments of GNSS Static and Real-Time Kinematic (RTK) methods were conducted and compared against conventional polygonometric surveying. Results demonstrate that GNSS Static post-processing provides horizontal accuracy of ±5 mm and vertical accuracy of ±8 mm, making it the most suitable method for rail alignment control. RTK mode offers efficient real-time accuracy for construction monitoring. An optimal control point spacing of 2 km is recommended for this type of infrastructure, with reduced intervals to 1 km in sections with terrain gradients exceeding 3%.