How Warner Land Surveys uses the Leica Nova TS60
Author: Andrew Griffin
Warner Land Surveys Ltd (Warner Surveys), founded in 1979, is one of the UK’s leading land and engineering surveying consultants. Having delivered over 11,000 individual projects over its 40-year history, Warner Surveys focus has always been on customer service, and quality data collection and delivery. The company strives to be the ‘go-to’ providers for quality surveys. As the company evolved, it quickly developed both construction and industrial departments to support an evolving client base.
“From our roots as a small land survey company to where we are now, we continue to provide a consistent, cost-effective service to support our clients with comprehensive ‘end-to-end’ solutions for all their survey requirements, from project concept to completion,” says David Hutson, managing director at Warner Surveys.
Three applications, one total station
The land and engineering surveying company uses a range of techniques and state-of-the-art measuring and positioning technology to ensure every project is carried out with precision, accuracy and the most cost-effective and safe survey solution. Warner Surveys’ go-to tool for project control network survey, verified ‘View Surveys’ and 3D movement monitoring is the Leica Nova TS60 – World’s most accurate total station.
“The Leica TS60 is the instrument Warner Surveys turn to for projects requiring an additional level of accuracy assurance. Being a 0.5-second instrument makes it ideal for manual monitoring schemes, and the surveying of large survey control point networks, particularly in the rail environment. We have also found an additional use for the TS60’s telescopic imaging capabilities in verified view surveys,” explains Hutson.
The examples below explain how using the TS60 Warner Surveys:
Performed a control survey with the highest accuracy to verify the control point network guiding the redesign of the Kings Cross station in London;
Helps its clients visualise precisely how its new project or development will look like by providing surveys to produce ‘verified views’;
Movement monitoring schemes for the 3D monitoring of façades or old buildings.
Control network survey for Kings Cross Station remodelling project
Countries are adapting and expanding their railway systems to mobilise the increasing urban growth and keep the economy on the move – London is no exception.
As part of Network Rail multi-million-pound programme to upgrade the East Coast Main Line in the UK, London’s Kings Cross station aged infrastructure will be replaced and redesigned. The plans to review the station include re-laid the track in a new layout, with a disused tunnel being reopened, allowing for six tracks into the station instead of the current four.
Warner Surveys were commissioned in early 2019 to undertake the reinstatement and re-survey of the existing survey control point network on the Kings Cross Remodelling project. Surveying this railway line requires capturing data with the highest precision and standards in the shortest amount of time.
“As this is a rail environment control survey, requiring a very high level of accuracy, we opted straight away for the TS60 to undertake all traversing and control point observations,” says Chris Gilks, Warner Surveys lead surveyor on Kings Cross Remodelling project. “It is the ideal choice for a large-scale control survey as it utilises the instrument’s strengths. The TS60 allows us to observe and record ‘rounds’ or ‘sets of angles’ to a 0.5 second horizontal and vertical accuracy, and as a result, provides quality data sets, which ensure we achieve the required accuracies necessary to meet demanding Network Rail standards.”
Accuracy is an important benefit, but this is not the only advantage of using the TS60 for control network surveys. During the Kings Cross Remodelling project, in addition to ground control observations, there is also a requirement to verify and coordinate several wall-mounted prisms.
“With projects such as this, with high numbers of targets, when utilising the Leica Captivate ‘Sets of Angles’ app, it was often necessary to observe 12 or more different ground and wall targets in face left and right for seven complete rounds. For example; for 12 targets this would equate to 168 control observations for a single set up,” explains Gilks.
This process can be very demanding on time, especially in the rail environment where access and time on site are at a premium.
“The TS60 is well suited to this task due to its Piezo technology endless drives as opposed to the standard motorised drives. The increased rotation speed of the TS60 significantly reduces the time to observe such large sets of angles so, in turn, increases our productivity per hour on-site and ultimately reduces costs for Warner Surveys and our client,” adds Gilks.
Verified view surveys
Warner Surveys has been a long-time provider of ‘Verified View’ surveys for Accurate Visual Representations (AVR). AVR, photographic images showing placed accurately within a new development in situ, are used by architects and developers, usually for planning purposes, to show how a future scheme might look. A photograph can be accurately placed and rendered into a 3D model to visualise a prospective site, collecting GPS and total station measurements.
Warner Surveys provide its clients, or the company producing the AVRs, the survey data to facilitate 3D digital modelling. Experts survey and record a large range of photograph reference points and the camera locations to ensure a high level of accuracy. The surveyed data collected by the team is then imported into the client’s 3D digital model from which render images of a proposed scheme can be rendered.
“The TS60, with its image capture capability, allows us to provide our clients with images of the recorded or surveyed reference points. It adds a telescopic image record of the point surveyed which facilitates post-processing and can be supplied to the client in order to confirm or prove the point surveyed,” remarks James Wallace, senior surveyor at Warner Surveys.
3D movement monitoring
Accurate and reliable positioning on the status of structures is crucial to make fast and informed decisions and react to potential problems.
It is a commonplace now for refurbishment works to require that the existing façade is maintained, whilst the internal structure is demolished and rebuilt to suit a more modern design. In these instances, the appointed design/structural engineers may request the installation of a monitoring scheme to monitor a façade or structure with millimetre accuracy.
Warner Surveys has monitored old buildings and façades using the TS60, as the robotic total station can determine its own position and orientation observing the control points set by the team.
“When Warner Surveys begin the process of the setting up one of these monitoring schemes we carry out three sets of angles observations to our reference control and to the monitoring targets over three set up positions for the base readings. The TS60 really comes into its element during this base reading set up due to its speed when turning between face left and face right, and when turning to observe the numerous monitoring points. The Piezo technology direct drives that turn the TS60 massively increase the speed at, which a monitoring scheme can be carried, which allows us to process and hand over results to the client quicker,” concludes Peter Pearson, monitoring manager at Warner Surveys.