Trimble S - Tracker (Autolock) collimation; Target ID; FineLock Technology

Chapter 3
Theory of Operation
Trimble S, VX, SPS & RTS Service Manual3 - 82 P/N 57150002, Revision 5.0
F
Tracker (Autolock) collimation
When the instrument is locked to a target, the cross-hairs viewed through the telescope should point
at the target’s center. Most units will have a small misalignment and this is normal. A tracker
collimation will store the misalignment error and use it to compensate for misalignment.
Target ID
The Target ID unit is an optional accessory with the Trimble Standard telescopic rod that allows the
instrument to identify a target before locking and tracking. The Target ID unit is mounted on the
reflector rod below the prism ring. An infrared LED, modulated with a certain frequency, transmits
a beam, which is received by a detector in the instrument. When the target is detected the instrument
will lock onto the prism using the Autolock system.
The Target ID unit is a single direction, manually activated device that is controlled by the operator
at the rod. Eight different Target ID channels can be defined, allowing multiple systems to be used in
the same area without interference.
FineLock Technology
The Trimble S8 Total Station is equipped with FineLock technology. Similar to Autolock, FineLock
technology is used to automatically aim the instrument towards a target, however in FineLock mode
the instrument uses only the fine detectors of the quadrant tracker receiver, the coarse detectors are
switched off. This makes it possible to position targets closer to each other especially useful in
engineering applications such as monitoring and tunnelling where multiple targets with very tight
spacing are used.
FineLock technology enables the Trimble S8 total station to distinguish between and measure to
targets that are placed very close together. Guidelines for target spacing can be are in the following
table.
To avoid disturbances it is recommended that FineLock mode is not used for distances shorter than
25 m when two prisms at different distances are in the field of view, see table above. The prism to be
measured (prism 1 in the figure) must be between d and 2d and the angle between both prisms > 0,25
gon (4 mrad).
FineLock is designed for measurements to static targets. It cannot be used to track a moving target
such as a robotic rod.
Range (d) 4 mrad Minimum Target Spacing
25 m / 82 ft 0,1 m / 0,3 ft
100 m / 328 ft 0,4 m / 1,3 ft
200 m / 656 ft 0,8 m / 2,6 ft
300 m / 984 ft 1,2 m / 3,9 ft
400 m / 1312 ft 1,6 m / 5,2 ft
500 m / 1640 ft 2,0 m / 6,6 ft