Herzog+Mandt GmbH to develop a better and more effective
solution. The goal was to have automated tracking with
measurements at timed intervals.
The solution was a Trimble S8 robotic total station with
Trimble VISION technology and a Trimble MultiTrack™ target.
Mandt was confident: “If we use all our surveying aids and
instruments to their full capabilities, we can achieve excellent
As the gondolas travel across the river, they are separated by
roughly 160 m (525 ft). A critical parameter in evaluating the
results is the lowest point of the trajectory above the water. The
weight of adjacent gondolas had no measurable effect on this
point, and neither did cable length, which can vary according to
temperature conditions. The temperature was recorded but no
correction applied as the cables can be hydraulically tensioned
at the return wheels of the top and bottom stations.
In order to carry out measurements, a gondola was loaded at
the top station of the cableway with a weight of 2,800 kg
(6,300 lbs), corresponding to the maximum permitted number
of 35 people. After a brief start-up at the top station, the prism
was fixed to the bottom of the gondola using a magnetic
base and extensions. Since the gondolas are constructed of
aluminum, an opening in the bottom of the gondola floor was
used to access steel beams where the team could attach the
magnetic base with the prism.
The gondola was then moved beyond the top support until it
was above the east bank of the Rhine, where it was stopped.
From this point on, the prism could be measured once per
second over a length of 500 m (1,640 ft) to a point over the
west bank of the river. “It was fascinating to see how the total
station automatically tracked the target as far as the support
at the valley station on the west bank of the Rhine,” observed
Frickel. “We could even see the survey results displayed on
the controller. The Trimble VISION technology built into the
S8 enabled images to be combined with the georeferenced
measurements recorded.” Even with the moving gondolas, the
measurements met the required accuracy of 1–2 cm (0.4–0.8 in).
By capturing images during the survey, the team could overlay
the survey data and confirm while still in the field that the data
was correct and the instrument had accurately tracked the
With UNESCO extending operational approval until 2026, the
transit path will be measured every year. Trimble VISION enables
complete image documentation of data, which can be referred
to in the event of safety questions. Each point is georeferenced
and can be subsequently checked in the office. The photogram-
metric functions in Trimble Business Center software also allow
additional detailed data to be extracted without additional
need for field visits.