Setting up a station for surveyors: a meticulous process

Land surveying is a slow and meticulous process that requires a high degree of precision. It is essential that all constructions (bridges, roads, residential and commercial buildings or any other infrastructure) are located in the right place. Any error can lead to exorbitant cost overruns. In the surveying profession, this is a challenge because, to stake out or survey with precision, you must first have the most precise setting up (positioning) possible.

Possible sources of error in setting up the surveying device

In setting up a surveying station, there are two risks of error: imprecise setting up (positioning) and a level error which is the misadjustment of the level of the rod. What interests us in this article is positioning error and how to reduce the risk for more efficient positioning!

Does relying solely on a surveyor's positioning system cause risks of errors in construction surveying?

When a surveyor uses a positioning system, he targets 2 to 3 different reference points. Then the surveying device's positioning system calculates and compensates by oscillating between the points used to swing.

What is wrong with the conventional positioning system that a surveyor has in construction?

The problem with the conventional positioning system in construction is that if the points used by the surveyor do not correspond to each other or if the layout is taken with a surveying rod, this leads to a positioning error that the positioning system positioning of the device (total station) must compensate by taking an average between its points. So for each station at different locations with the same landmarks, the positioning of the construction device will be moved from left to right and bottom to top.

Concrete example of a costly error of incorrect positioning of the device (Total Station) on a construction site

Let's say you are a construction surveyor and you set up in a location to stake out anchor bolts for a bridge beam and you have a tolerance of 5mm.

If your device's docking configuration is offset by 5 to 10 mm on one side and you then reinstall the device's positioning system (Trimble, Leica, Topcon or any other) in another location to stake out the other end of the beam, your configuration decompensates on the opposite side. Therefore, it generates an implantation error varying between 10 and 20mm.

Positioning errors caused by inaccurate stationing can quickly add up

In the example above, the inaccuracy of setting up the instrument is at least 10 to 30 mm. Additionally, if we consider the possible error caused by the level of the rod (which may be incorrectly adjusted), or human errors, it adds up quickly!

On the human side, when setting it up with the cane, it is very difficult for the surveyor to keep it straight (human error) and even if he manages to keep it level, 95% of the time the cane is incorrectly adjusted.

By adding all the aspects presented above in the example of bridge layout surveying, the inaccuracy in construction surveying becomes major, which can be very costly!

How can we improve the accuracy of construction surveys then?

For perfect consistency between different measurements and arrangements on construction survey setups at different locations, the human factor should be eliminated as much as possible.

How to eliminate human errors when setting up the device?

To eliminate human errors when setting up construction surveying equipment and to improve accuracy and speed, surveyors need fixed targets placed at strategic locations that can be aimed directly at. with the device, they guarantee perfect agreement between points over long distances in all kinds of conditions (including bad weather).

The targets ensure perfect positioning with optimal positioning speed to make life easier for construction surveyors with maximum precision.

A positioning system with reflective targets to improve construction station setup

TDR360 took a deep look at this problem and found the solution for surveyors. The secret to perfect positioning of the survey station (Total Station) with impeccable precision is to use fixed reference points that can be aimed directly with the device such as the TDR360 reflective targets or the targets 3D scanning.

No matter your type of instrument (Trimble, Leica, Topcon, etc.) simply place them in strategic locations. These very easy-to-use targets allow you to position your device extremely quickly with optimal precision.

Designed with top quality materials to give you: the best possible measurement feedback, regardless of the distance, and an excellent aiming angle, good weather or bad, if you see the target, it works!

Here is a video example of how it is used to improve surveying parking to build a road.

https://youtu.be/Wxn06sOYmEI