The precision of dimensional measurement plays an important role in guaranteeing the assembly accuracy of its internal components during the upgrading phase of EAST device. In this paper, the experimental research and analysis were done based on three dimensional combined measurement systems, combining Laser Tracker, flexible Measure ARM and measurement fiducials network, which are used for alignment and measurement of EAST components during the assembly process. The error sources were analyzed, e.g. temperature, gravity, welding, and so on. And the effective weight of each kind of error source was estimated by the simulation method. Then these results were used to correct and compensate the actual measured data, the stability and consistency of the measurement results was greatly improved in different measurement process, and the assembly precision of the EAST components was promised.
A precision spatial measurement network for EAST was studied and established base on the EAST configuration and Laser Tracker system. 34 fiducials in outside network and 64 fiducials in inside network were united in one cylindrical coordinate by a laser tracker system. Unified Spatial Metrology Network (USMN) analysis showed that the single point average uncertainty of this measurement network was about 0.2mm, which can meet the measurement accuracy requirements of EAST. A combination measurement method with a laser tracker system and measurement arm was used for the assembly process of EAST device and some researches of environmental temperature influence have been done to improve the measurement process.