60
2 PREPARATION FOR MEASUREMENT
• Prism type-2 (Normal prism)
• Prism type - 3 or 5 (Prism unit A2/A3/A6)
(Example)
In case Prism constant value (C) = 0mm, Prism inclination = 20°, Measuring distance = 100m by Prism
type-2 :
• Distance error is :
From the graph prism type-2, the distance error shows in increasing range quantity 2.5mm along
curved line of C=0 when prism inclination is 20°.
• Angle error is :
From the graph prism type-2, along curved line of C=0 with prism inclination of 20°, find angle error
quantity (14.2mm) and calculate angle error by the following formula.
C=40
C=30
0
30
20
10
22
12
8
-2
0
C=0
( mm )
5
4
2
0
( mm )
C=0
C=30
C=40
6
3
1
-1
30
20
10
0
Distance Measuring error
Angle measuring error
Inclined angle (degree)
Inclined angle (degree)
Increasing
distance
range
Angle error
range
4
16
Distance Measuring error
Angle measuring error
( mm )
Angle error
range
Increasing
distance
range
( mm)
Inclined angle (degree)
Inclined angle (degree)
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″