Fig. 1. Laser tracker measures the tunnel control network

Fig. 2. Laser tracker coordinate measuring principle

Fig. 3. Linac tunnel control network

Fig. 4. Result of 3D adjustment without height constraints

Fig. 5. Measuring station coordinate system and vertical coordinate system

Fig. 6. Vertical orientation 3D adjustment result

Fig. 7. Cartesian coordinate system and the geoid

Fig. 8. Elevation correction

Fig. 9. 3D adjustment result of Level elevation transformation method

Fig. 10. Difference of Starnet adjustment result and 2D+1D adjustment result

Fig. 11. Difference of 3D adjustment with elevation constraints result and 2D+1D adjustment result