As mentioned in the previous post, the Topcon GLS-2000 is a survey grade instrument that can be attached to a standard tribrach to allow occupation and backsight measurements over a known point. Previous Topcon GLS scanners used a bespoke highly reflective target that could be attached (magnetically or adhesively) to a special T mount or any flat surface. Whilst testing a production Topcon GLS-2000 laser scanner, we spotted an option under target scanning to make a backsight using a prism.
The target scanning process was very simple – tap on the live video image on the scanner’s screen to point roughly in the direction of the prism. The scanner then carries out a coarse scan and then a fine scan of the prism target. If the target scan is successful, a circular target is shown on the screen and a red laser dot appears from the centre of the prism. We tried out a Leica 360 degree prism, a Laserscanning Europe mini prism and a Topcon standard prism and all worked well. Obviously the scanner has to be told the prism offsets to give the correct coordinate.
The GLS-2000 has automatically detected a standard survey prism for a BS target
We’re particularly excited about this feature of the GLS-2000 because it means that there is much greater scope for projects like monitoring where standard prisms can be used. Overall it is a cost effective and fast way of achieving great results with kit that every surveyor has in the boot of his or her car.
