Leica GDF312 Basic Tribrach with Optical Plummet Ideal for GNSS
Model: GDF312
Specifications:
Torsional stiffness <3", weight 885 grams
Introduction:
The GDF312 (and the GDF311) Professional 3000 series tribrachs are
the mid-grade professional tribrachs from Leica.
The tribrach and optical plummet are of a robust construction and
suitable for long period exposure in all environments. This makes
the GDF312 ideal for GNSS and backsights and control points.
All Leica original tribrachs comply with the strict specifications
and quality standards of Leica Geosystems. Your choice should
ideally be made according to your individual accuracy requirements.
These tribrachs are suitable for non-motorised TPS instruments with
angle accuracy from 5" to 7" and GNSS antenna stations as well as
backsights and control points.
The torsional rigidity (or hysteresis) of the Professional 3000
Series tribrachs amounts to a maximum of 3" (1.0mgon).
The accuracy with which a tribrach returns to its starting position
once the instrument has stopped, is called torsional rigidity or
hysteresis. This hysteresis is the relative movement between the
top plate and the base plate of a tribrach that occurs through the
rotation of a TPS instrument. The hysteresis has direct influence
on the angular accuracy of the instrument – and that speaks for the
original. To optimize the hysteresis as Leica Geosystems has done
is complex and calls for the highest precision: a movement of the
top plate to the base plate of 0.3µm corresponds to an angle error
of 1". Especially motorized instruments with their high
acceleration and brake power require tribrachs with very high
torsional rigidity.
The foot screws are maintenance free and have a larger diameter.
This allows for fine adjustments, even when wearing work gloves
under difficult environmental conditions.
