1. Adjustment of the 3 reference tables at building 180 AT960 measurement
EDMS :
Adjustment of the 3 reference tables at building 180 AT960 measurement
Measurement :
The goal of these measurements is the levelling of the 3 reference tables which will support the cold mass in building 180.
The measurement was done the 15th May 2019.

3. INTRODUCTION

4. Synoptic (building 180) 3 reference tables Network of reference points
The picture below shows :
the different fiducials of the 180 network
The 3 reference tables which must be levelled
3 reference tables
Network of reference points

5. Coordinate systems (for information)
Different coordinate systems have been used during the measurement and for the report.
R-instrument (AT960 gravity)
This coordinate system is the coordinate system of the instrument.
It’s linked to the gravity (Z axis).
The orientation of axis X and Y are dependent on the zero of the horizontal circle of the instrument.
R-building 180
This coordinate system has been created for this report.
The primary axis is defined by the gravity defined by the AT960. The secondary axis is determined by 2 points of the network (p1, p4). The origin is p1.
X (mm)
Y (mm)
Z (mm)
Primary Axis : Z : AT960 gravity
Secondary axis : Y : p1  p4
X (radial) : cross-product
Origine : p1
R-180

6. During this measurement, there is no old data
A priori data
During this measurement, there is no old data

7. AT 960 measurements The measurement took place on 15th May 2019.
Vivien RUDE (VR) and Leonard Watrelot (LW) conducted these measurements.
Vivien Rude analysed the data.

8. AT960 measurement (details)
1 offset
support
Detail of the measurements
Day of measurement : 15 May 2019
Place : 180/R-V33
Operator : VR, LW
Material
1 Laser Tracker Leica AT960 +accessories (borrowed by Michel Parent)
1 CCR PLX 1.5 inches
1 offset support (3 mm in radial, 25 mm in vertical)
1 portable metrology tripod (Carbon)
1 computer with Spatial Analyser software
Measurement mode
Static mode (1 circle, 0.5 sec) for the reference points
Dynamic mode for the levelling of the reference tables
Prism constants
No prism constants have been used
A priori precision of the measurements
A 4h warming-up of the laser tracker has be done.
Dynamic measurement (empirical value)
Angles : 1.25 arc second = 6.1 microradians = 3.5 cc
Distances : mm +/- 1.5 ppm
Fast measurement  1 circle and 0.5 sec (empirical value)
Angles : 1 arc second = 4.8 microradians = 2.8 cc
Distances : mm +/- 1 ppm
Precise measurement  2 circles and 5 sec (empirical value)
Angles : 0.75 arc second = 3.6 microradians = 2.1 cc
Distances : mm +/- 1 ppm
Closing point
ST 1 : 14 µm (at 2.8 m)
Temperature
[22.5°C – 23 °C]

9. AT960 measurement Station AT960 Support 3 Support 2 Support 1 AT960
The sketch below (print screen from the Spatial Analyser) indicates the position of the instrument during these measurements.
Support 3
Support 2
Support 1
AT960
Support 3
Support 2
Support 1

10. AT960 measurement Reference table
On each support, the levelling will be done on the inner ring of the support (Blue area on the below picture).
An offset support has been used.

11. AT960 measurement Precision (R-180) X (mm) Y (mm) Z (mm) R-180 1.6 m
The 180 coordinate frame was used in order to display the precision of the measurements for each point.
The precision depends on the distance of the laser tracker, the measurement mode and the geometry of the different stations.
For the Support 1, the 3D-precision is around 85 microns.
For the Support 2, the 3D-precision is around 40 microns
For the Support 3, the 3D-precision is around 22 microns
1.6 m
4.0 m
9.4 m
Support 3
Support 2
Support 1
Ø=228 mm
Ø=228 mm
Ø=228 mm
Precision at 1.6 m
x (mm)
y (mm)
z (mm)
Support 3
0.010
0.017
Precision at 4.0 m
x (mm)
y (mm)
z (mm)
Support 2
0.024
0.021
Precision at 9.4 m
x (mm)
y (mm)
z (mm)
Support 1
0.056
0.029

12. RESULTS

13. Plane Fitting and plane orientation (after adjustment) Details R-180
X (mm)
Y (mm)
Z (mm)
Plane Fitting and plane orientation (after adjustment)
Details
R-180
The tables below describe the plane fitting done for each support after the adjustment of the 3 support. The adjustment has been done with the tools Watch window from Spatial Analyser.
The flatness of each support is below 20 µm (r.m.s.) and the plane orientation of each support with respect to the gravity is below 300 µrad.
The plane orientation calculated with the 3 supports is below 60 µrad with respect to the AT960 gravity.
Support 3
Support 2
Support 1
Support
1+2+3
Fitting result
Fitting
Plane
Z-Offset
25 mm
Nb point
42 points
Removed
points
2 points
Flatness
RMS
0.022 mm
Normal
vector
A (Rx) =
B (Ry) =
C =
Min Z mm
Max Z mm
Mean Z mm
Support 3
Fitting result
Precision
Sigma
à priori
0.010 mm
Fitting
Plane
Z-Offset
25 mm
Nb point
41 points
Removed
points
---
Flatness
RMS
FUV
FUV = 1.01
Normal
vector
A (Rx) = +/
B (Ry) =
C =
Min Z mm
Max Z mm
Mean Z mm
Support 2
Fitting result
Precision
Sigma
à priori
0.024 mm
Fitting
Plane
Z-Offset
25 mm
Nb point
39 points
Removed
points
1 point
Flatness
RMS
0.018 mm
FUV
FUV = 0.58
Normal
vector
A (Rx) = +/
B (Ry) =
C =
Min Z mm
Max Z mm
Mean Z mm
Support 1
Fitting result
Precision
Sigma
à priori
0.056 mm
Fitting
Plane
Z-Offset
25 mm
Nb point
42 points
Removed
points
1 point
Flatness
RMS
0.016 mm
FUV
FUV = 0.09
Normal
vector
A (Rx) = +/
B (Ry) =
C =
Min Z mm
Max Z mm
Mean Z mm

14. Z values Support 3 Support 1 Support 2 Z (min-max) = 0.132 mm
The graphic below represents the Z value of the measured points (with a shift of 25 mm in vertical in order to canceled the offset support) after the adjustment.
All the Z values of the 3 supports are identical at 132 µm.
Support 3
Support 1
Support 2
Z (min-max)
= mm

15. Z values X (mm) Y (mm) Z (mm) R-180 Support 3 Support 2 Support 1
The graphic below represents for each support the Z value of the measured points (with a shift of 25 mm in vertical in order to canceled the offset support) after the adjustment.
R-180
Support 3
Support 2
Support 1
Support 3
Min Z mm
Max Z mm
Mean Z mm
Support 2
Min Z mm
Max Z mm
Mean Z mm
Support 1
Min Z mm
Max Z mm
Mean Z mm
Z (min-max)
= mm
Z (min-max)
= mm
Z (min-max)
= mm

16. CONCLUSION
The goal of these measurements was the levelling of the 3 reference tables which will support the cold mass in building 180.
The flatness of each support is below 20 µm (r.m.s.) and the plane orientation of each support with respect to the gravity is below 300 µrad. The plane orientation calculated with the 3 supports is below 60 µrad with respect to the AT960 gravity.
All the Z values of the 3 supports are identical at 132 µm.