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10. TARGET SIGHTING AND MEASUREMENT
Appropriate prism for Auto Pointing and Auto Tracking
<Single prism>
The prism center is sighted optically during Auto Pointing and Auto Tracking operation. Therefore angle
error will be caused depending on the prism constant values of the prism to use when it is not positioned
in alignment with the objective lens of the instrument. The following recommended prisms with the
described prism constant correction values are optically designed to eliminate the angle error. Those
prisms with the described prism constant correction values enable accurate measurements without taking
care to face the prism toward the instrument.
When using prisms other than shown above, make sure to face the prism toward the instrument to keep
the angle error as small as possible. (How the measurement error is caused is illustrated below).
Targets available for the iX: "24. TARGET SYSTEM"
<360°prism>
360
°
prisms reduce the possibility of "lost prism" during Auto Tracking measurement regardless of the
direction of the prism.
Details of 360
°
Performing high accuracy measurement using 360
°
prism:"27.1 High Accuracy with the 360° Prism"
Prism
Prism constant
correction value
Note
AP01
-40
Directly attach AP01 whose
constant correction value is "-
40" to the tilt mount as
indicated left.
(Illustration is the Single tilt
mount AP11)
Prism
Prism constant correction value
ATP1/ATP1S
-7
How the measurement error is caused
Measurement point
When setting prism constant correction value to 0mm
When setting prism constant correction value to an appropriate value
Prism
Prism
Measurement point
Measurement error
Actually measured point
Actually measured point
Gap from the position the prism is facing toward the instrurment
Gap from the position the prism is facing toward the instrurment