engleski

Independent control of geodetic networks above long tunnels by means of astronomically determined azimuths

The work presents the automated astronomical method of determining azimuth and grid azimuth toward to some object on the surface of the Earth. The accuracy of astronomical azimuth determination by observing Polaris with electronic thedolite Kern E2 and Leica T3000 amounts to ą0.4". Such high accuracy in grid azimuth determination enables the control in setting the direction for the tunnel cutting. The paper also describes the application of this method and computation of the influence that the deflection components of the vertical have during the independent control of geodetic networks above the tunnel Chiffa in Algeria and the tunnel Nevesinje in Bosnia and Herzegovina. They are longer than 12 km. The application of astronomical method in azimuth and grid azimuth determination makes it possible to obtain the control of geodetic network accuracy with another independent method. At the same time, the deflection components of the vertical are also controlled. They can significant to influence on the orientation of traverses at the entrances into tunnels, especially if the line of sight to the orientation points are steep. It is also very important in modern GPS technology.

control of geodetic networks; long tunnels; astronomically determined azimuths

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