Shaping up

29 March 2017

Tunnel navigation specialist VMT has partnered with US geo-positioning expert Topcon to create what they claim is the best solution yet for deformation monitoring

Herrenknecht-owned VMT is well known for its tunnel navigation systems, which it has sold to thousands of projects since its establishment in Germany in 1994. In April 2016 it announced that it would partner with global positioning specialist Topcon to create the Topcon Delta range of deformation monitoring products. “It consists of the Delta Link Unit in combination with a Topcon total station,” explains Sascha Schneid, product manager for deformation monitoring and innovative systems at VMT. “The total station takes readings from prisms and the Delta Link unit is a data logging device, which takes the readings from the total station and transmits this to a server where the Delta Watch software is running,” he explains.

The software takes these readings and performs statistical analysis to determine the movement between the monitoring points and the reference points as well as using a sophisticated geodetic algorithm to check the quality of the data. “It tells you relative to a reference frame whether one point has moved or not and it also gives a quality measure so there is also a measure for the reliability of the result.”

This means that the system complies with the ISO 9000 standards of quality control, which is embedded even in its most basic software so comes as standard in its products. “That is what makes it different from competitors’ products. It is not just giving information, it also gives measure of the reliability and quality of the information,” says Schneid. “You can rely on our data.”

You can also rely on the security of the data, says Schneid, who explains that the data logger shares the information via the internet using a secure encrypted transmission.

There are other advantages for tunnelling in particular as the software is also able to incorporate geotechnical information such as groundwater measurement, ground conditions or underground instrumentation. “In general this is appropriate for all tunnelling projects. It could be a TBM or excavator or cut and cover. There is no limitation. The software is modular and if there are any special requirements we can easily customise this by adding a module. For example in excavation it could be necessary to install monitoring inside the tunnel,” says Schneid.

In addition to the Delta Link and Delta Watch the system also has the option to use GNSS data measurements using the Delta Sat add on. “The standard system takes the readings from the Topcon total station and the Delta Sat now uses satellite systems - GNSS. This is an optional thing,” says Schneid explaining that for tunnelling the Topcon total station would be used for monitoring. Another update that the system has is that the field hardware has been redeveloped to make them lightweight and easy to handle while maintaining durability and performance. “The Topcon total station is also very robust, very precise and also user friendly. It comes with several functions designed for monitoring that make life easy for people in the field,” says Schneid. This includes for example the Matrix Detection function that comes as standard with the Topcon MS total station. “It enables a reflector pre-scan that automates the configuration of the prisms when the system is commissioned. Having this assistance, the field crews save a lot of time,” says Schneid.

New partnership

For Topcon the decision to pair with VMT was a perfect fit. Topcon’s global distribution network combined with VMT’s heritage is described by Topcon business development manager Chris Emery as an exciting partnership. “Our product managers looked at doing something in house and then looked at if any reputable expert organisations were interested in partnering and developing a product. Conversations were struck up with VMT. It didn’t take very long at all for both organisations to realise that this is a really nice fit and monitoring is only just the start,” he says.

The first Topcon Delta units were shipped in October. These early customers are experienced monitoring firms who will feed back their experience to Topcon.

“We have had a significant amount of interest. For off the shelf solutions there was a very limited number available on the market. We have had a lot of interest and a lot of enquiries from people that have been using other systems and want to test it and have indeed ordered it.”

Topcon says that the system is not only designed for monitoring companies. “If tunnelling contractors feel like they have the relevant expertise within their organisation to deliver the monitoring requirements then they can purchase the Delta solution and use it themselves, alternatively if they would prefer to subcontract out the works to a specialist monitoring contractor then these are also our target audience,” says Emery noting that the software presents the data but does not provide interpretation. The number of configuration tools for processing the data is one of the systems key advantages he says.

At the same time Emery says that he is in the process of setting up a demonstration site in Europe. “We can also go to people with the hardware and the software and do a day’s demonstration and testing at their offices and where we can we will try to leave systems with them to test themselves and get used to it”

Working with Delta Watch - analysing total station measurements
The Delta Watch software provides sophisticated functions for planning and analysing terrestrial network
Besides the standard tools for processing Delta Watch provides simple but meaningful tools for data visualisation