High-Precision Triangular Elevation Measurement Based on Correction of Refraction Coefficient of Unsteady Space Atmosphere

In practical engineering, precise triangulation elevation measurements are required for the construction of large-span bridges across rivers. During this process, the atmospheric conditions above the water area exhibit complex and varying states in different times and spatial locations. The collection of environmental parameters such as temperature and pressure in the airspace above the water area is extremely difficult, making it impossible to establish a stable spatial atmospheric refraction coefficient model that satisfies high-precision triangulation elevation measurements. In this paper, based on the method of mathematical statistics, ignoring the atmospheric environment parameters, a non-uniform atmospheric refraction correction model is constructed according to the variation law of the atmospheric refraction coefficient in a certain time and space. Through combinatorial optimization and iterative calculation, the interference of atmospheric refraction coefficient in unstable space is solved to a certain extent. This method does not need to solve the problem of collecting atmospheric environmental parameters, and continuously adjusts the atmospheric refraction coefficient suitable for different time and space through program design. This method is effectively applied in a large-scale cross-river bridge under construction. At the same time, the algorithm design has strong practicability and flexibility, which greatly improves the accuracy of triangular elevation measurement in the unstable space of cross-river monitoring.