Update Setups; Terminology - Leica GPS1200 Series Technical Reference Manual

Update Setups

33
33.1
Description
Setup
Backsight
Unknown backsight
point
Update Setups

Terminology

This chapter describes technical terms related to Setup.
Setup is an application program on TPS1200 instruments. It can be used to orientate the
TPS1200 instrument.
In a TPS survey, the instrument is set up over a point.
A reading onto a fixed point of reference, usually a benchmark of some sort, is taken in order
to orientate the instrument. This reading is called backsight.
Since a survey progresses from a point of known position to points of unknown position, a
backsight is a reading looking backward along the line of progress.
A point with unknown coordinates used as backsight point is called unknown backsight point.
It may happen that at the time of a set up, the coordinates of the backsight point are not
known yet. The survey starts with wrong angles. The coordinates of the backsight point are
determined later by a COGO calculation, for example, or by GPS.
If the coordinates of the unknown backsight point are determined, the setup using this back-
sight has to be updated in order to correct the angles. Additionally, the coordinates of all TPS
measurements related to this setup must be recalculated.
GPS1200 742