Mobile laser scanning (MLS) technology can be a game-changer when it comes to planning and executing many civil engineering projects, and with innovations set to revolutionise the way traditional surveys are carried out, can businesses afford not to invest? Liene Starka, our MLS product manager discusses how to build a business case to access the benefits of mobile LiDAR.
Justifying a large capital investment can often be tricky when the ‘powers that be’ don’t always have a working knowledge of the challenges which arise during the course of any civil engineering project. As many surveying and construction businesses have invested in terrestrial laser scanners in recent years, it becomes more difficult to substantiate reinvestment just because the technology has advanced. The key to building any business case relies in proving that: A, the investment will solve a problem and B, that it will provide a return on investment. In the case of mobile LiDAR, both are easily demonstrable.
Scope & Benefits of Mobile Laser Scanning
All LiDAR (Light Detection and Ranging) systems are capable of gathering enhanced intelligence of the immediate landscape, including buildings, transportation networks and existing infrastructure. The collected information can be used retrospectively in the form of a three-dimensional map to allow for key decisions to be made prior to a project breaking ground.
One of the main benefits of mobile LiDAR is the speed at which surveying tasks can now be completed. Where terrestrial laser scanning systems (TLS) rely on multiple set ups to generate a map of a large site, mobile systems are capable of collecting accurate data in a continuous stream. Multi-use systems, such as ROBIN, can be mounted onto a moving vehicle or airborne unit, as well as a backpack, to ensure that any site can be surveyed in its entirety in one visit.
The time saving benefits alone can make mobile laser scanning a must when projects need to get underway. Carrying out feasibility studies such as site appraisals, geotechnical studies and adjoining land assessments can be carried out around 80 per cent faster using MLS, with only one operator needed to manage the equipment.
The collected data is simple to extract and process, and here lies the true scope of the technology. The most advanced MLS systems are capable of collecting around a million points, or measurements per second, enabling dense point clouds to be generated which can then be used to provide a situational analysis for the preparation of a clear project path. When used with an Inertial Measurement Unit (IMU) and GNSS (Global Navigation Satellite System), the points collected by the laser scanner are put into a real-world context in terms of global positioning, with achievable accuracies of around 7mm.
Previously, mobile mapping data was difficult to process due to the sheer amount of information collected. Software such as Terrasolid is now designed around mobile LiDAR systems to allow for the data to be manipulated in different ways for numerous uses. Classification routines enable the automatic filtering of the point cloud to take it from an initial digital surface model, showing all built and natural features including vegetation, to a bare earth model where only the elevations of the landscape exist. It is also possible to identify or extract specific features from point cloud data, such as buildings, trees or powerlines, as well as create 3D vectors based on laser points.
The ability to manipulate the data to such a degree makes it accessible and meaningful to multiple stakeholders in any project. Another benefit of mobile systems is the ease of set up and execution, meaning that time-series scans can be carried out at various stages without having to dedicate hundreds of additional man-hours. Progress can be monitored to ensure that things are on track and there have been no changes in the environment, which could impact on either site safety or advancement of the project.
Risks to Reward
Calculating risks in any civil engineering project is one of the first and most important tasks. This is another area where the benefits of mobile laser scanning dominate in the field of surveying. Previously, land surveyors would be sent in to the field to identify and classify risks using total stations or TLS systems. Often this would mean being exposed to hazardous conditions or heavy machinery, where the risk of injury is ever present. Using a mobile system, whether attached to a car, truck or drone, means that the risk to operatives is minimised. All data is collected remotely and continuously.
The resulting data from a mobile system also helps when assessing the actual risks on site, as time series scans can help to detect new issues that may arise part way through the project. A comprehensive and updatable risk model can be introduced which contains greatly detailed information, allowing risk to be managed, rather than responded to. This can allow immediate action to be taken to prevent or even rectify issues before they cause either harm or delays to the continuation of the project.
In the same way that MLS systems can help to improve site safety and lower risk to human lives, they can also lower costs associated with planning and monitoring even smaller scale projects. Systems, such as ROBIN, take around five minutes to initialise – around the same time it would take to set up a TLS scanner and mount it to a tripod. Yet, once the system is set up, it can continue to scan for as long as the data capacity will allow.
There are further resource and time savings offered by the fact that mobile systems not only save on the time taken to collect the actual data but they can also be operated by a lone worker. In addition, the previously mentioned point clouds can be assembled or disassembled in layers depending on what information is needed and for what purpose. This means specific measurements can be extracted at a future point in time without the need to return to the site. When you combine the quality of the data generated by a mobile mapping system with the time saving benefits, project costs can be greatly reduced.
Mobile Laser Scanning: Metrics for Measurement
Technology spending has no value without measurable business impact. This impact must be publishable to partners and stakeholders so that financial reporting obligations can be met.
Whether a business is looking to purchase a mobile LiDAR system for its own use, or a planning team is looking to procure the services of a surveying company with LiDAR at its disposal, certain expected deliverables will be set based around quality of data, timescales and the total cost of the system or survey. Mobile systems are now available with survey-grade IMUs to provide immensely accurate data sets and the expedited collection method ensures that surveys can be completed quickly and methodically.
If a business case is being completed for a capital purchase of a mobile mapping system, it will be the ability to scan without stopping that appeals to most decision makers, meaning that more data can be collected in less time so that the system can be used for more jobs. Often, when a business attempts to save money by cutting costs or saving time, there is a dip in quality and productivity; with mobile laser scanning, it is possible to save time and money yet also realise improvements in operational efficiency.
Building a business case for new technologies can be challenging, yet mobile laser scanning is a perfect example of how disruptive technologies are replacing over-complicated processes whilst improving results for businesses and their clients.