Using astronomical leveling in the modern geodetic support system

With the advent of zenith camera, it became possible to improve the accuracy (up to 0,1″) and efficiency (no more than an hour) of measuring the plumb line deviation components at the point where the device is located in real-time mode. This enables measuring the components of the mentioned deviation at 4–12 or more points, depending on the season, during one observational night. Zenith camera is field-based, relocatable and can quantify the required components with any given discreteness, the process is fully automated. This makes the possibility of using the well-known method of astronomical leveling in a new way to define the height differences of the quasi-geoid. With a mistake in computing the deviation of a plumb line of 0,2″, the error in determining the elevation of the quasi-geoid heights is less than 1 mm at a kilometer distance between the points. This indicator is comparable with miscalculating of existing levels. In this case, there is no need for direct visibility between measurement points, computations can be performed between unrelated spots, and the distances between them can be kilometers or dozens of them. The authors present reviews of works on the use of zenith camera in creating quasi-geoid height models, develop the theory of astronomical leveling, consider its errors, and compare it with other leveling methods.