elded 
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led at 
other 
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rthest 
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tively 
s the 
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After all nodes summarized, the related node distribution can be 
seen clearly in Figurell. For checking the accuracy of the 
method, several nodes is selected to be measured by TCA2003, 
we can see that the two floats have the same trend and there are 
errors between corresponding nodes due to the position diversity 
of surveying points. 
TCA2003 
  
  
  
  
HDS3000 
AE 
  
  
B13 C13 DI3 E13 F13 G13 H13 J13 K13 L13 M13 N13 P13 Q13 
[E 
  
  
  
Figurell data contrast between HDS3000 and TCA2003 
4.3 4.3 Installation and Quality Monitoring of Steel-shell 
of Tianjin West Station 
Tianjin west station engineering is Asia's largest railway station 
building engineering, and it's an important joint project in the 
establishing of Jinghu high speed railway. The construction area 
of this project is about 22.9 million square meters, and large 
span truss shell steel structure between east and west is 394.063 
  
EN 
    
  
  
  
  
  
  
Figure 13 Scanning sites and control network of Tianjin 
West station building 
m, overall length is 114m, the Height is 47m, and the total steel 
structure weight is 18000t. Station building engineering roof is 
arch structure .According to the site; it was divided into north 
area, central district and ascent part. The process of ascension of 
the total height is divided into three stages. In order to assure the 
final joining precision, it is necessary to measure all the 
interfaces before and after timely lifting, and the mosaic roof 
structure which maintains the steel frame should be taken 
overall deformation measurement before and after upload. 
  
Figurel2 Tianjin west station building 
4.3.1 Combination of Multi-types Scanners 
For reducing the effect of control connection error, Leica 
TDA5005 is used in control network surveying. The accuracy in 
ranging of instrument is 0.2mm and precision of angular 
accuracy is 0.5”. As shown in figure 13, seven control points 
are in first district in control network (T1 — T7). 
Tianjin west station has more net shell ascending interface and 
the field occlusion is serious. For ensuring the accuracy and 
speed of measurement, combined mode scanning with 
medium-range  (HDS6000) and  remote-range scanner 
(Scanstation II) is used. Figurel3 show Scanstation II sites, the 
big circles mainly scan the top interface, the residual are 
HDS6000 scanning sites. In the scanning process, remote 
scanner and control network can be measured jointly. To avoid 
splitting error accumulation in short-ranged sites, the scanning 
areas are separated into blocks; each block contains partial 
temporary control points so that the data could be transformed 
into the control coordination directly. According to the actual 
port scanning density, the actual interface determined as the 
scale 8mm point spacing. 
4.3.2 Feature Points Extraction 
Sphere targets are used in registration of point cloud. Each block 
is registered firstly, then the block could be transformed directly 
into the control network with control points, thus error 
accumulation can be avoided. The registration error is 45mm. 
In actual analysis, design coordinate system is used as reference 
coordinate system, the whole extraction of feature points and 
corresponding feature points design are matched with 
least-square adjustment method, thus the target point get unified 
with design coordinates. The transformed feature points that 
extracted could be made compare with designed corresponding 
feature points. As can be seen above, the data connection error 
is within 2mm, which can meet the practical measurement needs 
completely.