Chapter 3
Theory of Operation
Trimble S, VX, SPS & RTS Service Manual3 - 36 P/N 57150002, Revision 5.0
F
Angle Measuring System
Trimble total stations have traditionally been leading in producing high measuring efficiency with
servo driven total stations admitting full angle accuracy in single-face measurements. The concept
with measurement and automatic correction of horizontal and vertical collimation errors and tilt axis
errors is still valid. Now, a new step in the direction of improved angle measurement and servo
function has been taken with the design of a new fully integrated servo and angle measuring system.
A new dual-axis level tilt sensor is also part of the system handling traditional levelling errors.
Angle sensor
The purpose of the angel sensor is to generate a vertical and horizontal angle for the instrument. The
angle sensor is based on an optical principle. Glass circles hold a pattern consisting of a coarse code
and a fine code admitting the presentation of an absolute angle value. Several improvements of
previously used principles have been made and are now under patent applications.
Location of angle unit
Fig. 3-35 Angle unit location
Technical specifications
• 1"-2" standard deviation depending on instrument model.
Vertical angle disc
Horizontal
angle disc
MSB board
MSB board