Three Benefits of Using Location Information in Indoor Construction Management: Real-World Examples of Shorter Construction Time, Improved Safety, and Enhanced Quality

On indoor construction sites, GPS positioning often does not reach, creating a challenge in accurately determining the locations of workers and equipment. In large buildings and underground works, it can take a long time to find "who is where" and "where the necessary equipment is," and this often leads to schedule delays and reduced work efficiency. Moreover, when workers' whereabouts cannot be ascertained, safety management remains a concern. In construction quality inspections, it is also not uncommon for rework to occur because positional discrepancies go unnoticed.

However, in recent years technologies have begun to emerge that enable the use of location information even indoors where GPS signals cannot reach. Using IoT sensors, positioning devices, and AR (augmented reality), initiatives to visualize in real time the locations of "people" and "things" on construction sites are spreading. DX (digital transformation) is progressing in the construction industry, and especially with the 2024 problem※ driving the need to address labor shortages and reform work styles, the use of indoor location information is becoming an indispensable element for improving productivity and ensuring safety at construction sites.

This article explains the three benefits of leveraging location information in indoor construction management—"reduced construction time", "ensured safety", and "improved quality"—illustrating each with concrete examples. Additionally, at the end of the article we touch on simple surveying methods using the latest technologies and offer ideas for implementing them on site.

※The 2024 problem: This refers to the situation in which regulations on overtime work for the construction industry will be applied from April 2024, making labor shortages and productivity improvement urgent issues.

Table of Contents

• What does utilizing location information in indoor construction management mean?

• Three benefits of utilizing location information - Benefit 1. Shorter construction schedules - Benefit 2. Ensuring safety - Benefit 3. Improved quality

• Technologies and key points for implementing location information indoors

• Summary

• FAQ

Utilizing location information in indoor construction management

Even if you say using location information in indoor construction management, some people may not immediately picture it. Simply put, in places where GPS does not reach, such as inside buildings or underground, it means digitally tracking the current locations of people, equipment, and materials, and visualizing site conditions. Specifically, information such as which floor and where on that floor workers are working, where tools and equipment like aerial work platforms are located, or whether installations are being placed according to the design drawings is obtained and shared in real time or on a regular basis.

Various technologies are used to leverage indoor positioning information. For example, one approach is to deploy sensors at construction sites (BLE beacons and ultra-wideband (UWB) tags) and attach small tags to workers and equipment to detect their positions. There are also technologies that combine smartphones or tablets with high-precision GNSS receivers to perform centimeter-level positioning (cm-level, half-inch-level) even at indoor–outdoor boundaries. Furthermore, 3D laser scanners and cameras can be used to capture interior construction conditions as point cloud data, creating construction records with positional information. In short, the purpose of utilizing positioning information is to establish an environment where even indoors you can instantly grasp "who, what, where, and what condition" through data.

Traditionally, identifying locations indoors required searching by teams of people or surveying while cross-checking paper drawings. However, with the digitization of location information, managers can view the site situation at a glance on a computer or smartphone screen. In the next chapter, let's look at three specific benefits gained from using location information in this kind of indoor construction management.

Three Benefits of Leveraging Location Information

When a location information system is introduced into indoor construction management, what positive changes occur in site operations? The main benefits are "shortened construction period (efficiency)", "safety assurance (prevention of industrial accidents)", and "quality improvement (precision management)". Below, each point is explained with an image of actual job sites in mind.

Benefit 1. Reduced construction time (Improved work efficiency)

Visualizing location information significantly increases on-site work efficiency and, in turn, shortens construction schedules. On large sites, it cuts down on wasted time spent searching for needed items or struggling to locate and call the person responsible for the next task.

Reduction of time spent searching for equipment and materials: In large buildings, simply searching for and walking to items like aerial work platforms, stepladders, and toolboxes can waste valuable time. By implementing a location information system, you can see the whereabouts of equipment at a glance on maps on smartphones or PCs. For example, when a location information system was trialed at an interior construction site in a 10-story building, the time spent "walking around the site because the aerial work platform couldn't be found" was almost eliminated. As a result, the time spent searching for equipment was reduced by more than 40% in some cases. The time saved through daily accumulation directly contributes to shortening the overall construction period.

Real-time progress tracking and workflow optimization: If the locations of workers and teams can be tracked, scheduling adjustments—such as "begin the next process immediately after a task is completed"—become smoother. Site supervisors can monitor progress at various locations remotely and make flexible decisions, such as redirecting personnel who are waiting to other tasks. As a result, idle time is reduced and efficient, waste-free process management is achieved. For example, by confirming in the system that a plumbing team has finished work and immediately handing the site over to the interior team, there have been sites where a process that used to start the next day could be started on the same day. In this way, leveraging location information eliminates unnecessary time loss and contributes to shortening the overall project schedule.

Benefit 2. Ensuring Safety (Prevention of Occupational Accidents)

The use of location information is a powerful tool for protecting the safety of workers on site. By constantly knowing the locations of people and heavy equipment, you can detect hazards before they occur and respond quickly in the event of an accident.

Entry detection and warning for hazardous areas: If hazardous zones (such as crane operating ranges, high-elevation work areas, no-entry sections, etc.) are preconfigured in the system, it is possible to warn workers with an alarm when they approach those areas. For example, at one plant construction site, the working area of heavy machinery was designated with a geofence, and a system was implemented where a buzzer on the helmet sounds if a worker gets too close. This has greatly reduced the risk of collisions between heavy machinery and workers. In addition, more sites are adopting systems that integrate vehicle movements—such as forklifts and trucks—to prevent near-miss incidents with pedestrians.

Rapid emergency rescue and personnel management: Even if a worker becomes unable to move due to an accident or illness, having location information enables a swift response. Wearable sensors monitor workers' movements and vital signs, and there is a system that notifies managers immediately if a fall or prolonged immobility is detected. In fact, at one site, when a worker collapsed, the sensor responded and nearby colleagues were able to rush over within minutes, preventing a serious outcome.

Furthermore, real-time location information is useful in situations where personnel evacuation must be confirmed before hazardous work, such as tunnel construction or demolition sites. For blasting operations, presence was traditionally confirmed by calling out and roll calls, but because the system allows you to see at a glance whether everyone has evacuated to the safe zone, it prevents human error and ensures reliable safety. In this way, the use of location information contributes to the prevention of workplace accidents and to minimizing damage if an incident does occur.

Benefit 3. Quality Improvement (Improvement of Construction Accuracy and Inspection)

The use of location information also contributes to ensuring and improving construction quality. This is because digital location data proves powerful when executing work at the precise positions shown in design drawings and when inspecting the finished results.

Improving the Accuracy of Surveying and Layout Work: In interior construction, layout work to determine the installation positions of walls and equipment—known as "sumi-dashi"—has traditionally been done manually using tape measures and laser layout devices. By using positioning and location-information technologies, layout points can be digitally specified based on coordinates on the drawings, enabling accurate installation with minimal error from the first attempt. For example, if reference points are obtained using an indoor positioning system or a high-precision GNSS receiver installed inside the building, and positions for piping or partition walls are marked based on that data, a deviation of even a few centimeters (a few in) is less likely to occur. If installations are correct the first time, rework and redo are reduced, preventing schedule delays caused by quality defects.

As-built inspection and early correction: Having positional information makes it smoother when checking the as-built condition (finished shape) after completion or at each stage. For example, by measuring the site immediately after construction with a 3D scanner or a camera equipped with positioning capability and overlaying the resulting point cloud data or photos onto the design data, you can determine at a glance whether the finish matches the drawings. If a slight shift or tilt is found, it can be immediately corrected at a timing that minimizes rework. In fact, in one interior construction project, AR technology was used on-site to overlay the design model and the constructed elements for checking, allowing a wall position shift of several centimeters (a few in) to be detected and corrected on the spot. This has enabled a smooth handover without receiving remarks in later inspections.

Quality records and traceability: Keeping construction records and inspection results with location information offers benefits for future maintenance and quality assurance. If you save photos together with location data in the cloud showing which component is located where in the building, you can quickly refer to them later when you want to check, for example, “the drawings indicate a pipe should be here, but what is it actually like?” Even if construction defects or flaws are found, the records allow you to trace the situation at the time of construction, making root-cause analysis easier. This kind of quality control based on reliable data reduces variability in construction accuracy and helps improve customer trust.

Technologies and Key Points for Implementing Indoor Positioning

So far we have outlined the benefits, but some of you may be wondering, "What do we actually need to do to make use of location information indoors?" There are several technology options for realizing indoor positioning, and each has its own characteristics.

Positioning using fixed sensors: One method is to install multiple sensor devices inside a building and measure positions using radio signals. BLE beacons, Wi-Fi access points, or high-precision UWB antennas are deployed throughout the space to detect signals from tags attached to workers and equipment and determine their locations. It is suitable for continuously monitoring wide areas, but initial installation can require effort and cost.

Simple surveying with mobile devices: Another approach is to use a handheld positioning device to measure the location of points as needed. Recently, small GNSS receivers that can be attached to smartphones and tablets have appeared, and there are products that can perform surveys with centimeter-level precision (cm level accuracy (half-inch accuracy)). A representative example is a device called LRTK. By attaching LRTK to a smartphone, anyone on site can easily perform high-precision positioning alone. Tasks that traditionally required specialized survey teams and large equipment can be carried out with LRTK, which fits in a pocket. For example, if you measure reference points inside and outside a building with LRTK, you can obtain latitude, longitude, and height at any indoor location or perform positioning according to coordinates on design drawings. Even workers without special training can share survey data to the cloud via smartphone operation and let all stakeholders view the location information, making information sharing across the entire site smooth.

As a point when introducing a solution, it is important to first clarify on your site "what you want to visualize." Whether you want to continuously monitor people’s movements or measure and record dimensions and coordinates at key points will determine the appropriate technology. If you want to manage the safety of multiple work groups on a large site, a sensor-installed indoor positioning system will be effective. On the other hand, if you want something that can be easily brought into an existing site or if your primary purpose is quality inspection or as-built measurement, a mobile positioning solution such as LRTK is suitable.

Fortunately, recent equipment and services have become more affordable and easier to use, making it simple to start with small-scale projects or pilot implementations. By "first trying it out on site," companies can realize the benefits of leveraging location information and increasingly move toward full-scale adoption. The important thing is to adopt the technology in a way that fits on-site challenges without forcing it and to ensure it becomes established. Effective use of location information will be a major differentiator in construction management going forward.

Summary

The use of location information in indoor construction management brings three major benefits: shortened construction schedules, enhanced safety, and improved quality. By visualizing site movements that were previously hard to see, wasted time and near-miss incidents can be reduced, and construction accuracy can be increased. The construction industry currently faces challenges such as labor shortages and constraints on working hours, but actively leveraging digital technologies is one key solution to overcoming these issues. Among these, location information is essential for capturing the real-world site as data and applying it to management.

Fortunately, in recent years technologies and tools for acquiring and sharing indoor location information have advanced dramatically, lowering the barriers to on-site implementation. In light of the benefits introduced in this article, why not consider trying to leverage location information in a project at your company? Even if you start with only some sites or specific use cases, the insights you gain from actually using it should be substantial.

The use of location information in indoor construction management will become a key element for future "smart construction" and on-site DX. Leading companies are already incorporating IoT and simplified surveying devices (for example, LRTK) and beginning to see results. Take this opportunity to realize improvements in productivity and safety through site visualization, and leverage them to strengthen your competitiveness.

FAQ

Q1. What specifically does using location information in indoor construction management mean? A. It refers to identifying the whereabouts of people and equipment at sites where GPS cannot reach, such as inside buildings or underground, by using sensors and positioning devices, and leveraging that data for site management. For example, imagine being able to confirm in real time on a map where a worker is currently working or where required equipment is located within the facility. Using location information to "visualize" the site situation is a method for managing work efficiently and safely.

Q2. What technologies are needed to obtain location information? A. There are several methods. One is an indoor positioning system in which transmitters and receivers such as BLE beacons or UWB antennas are installed inside a building and positions are determined from signals from tags attached to people or objects. Another is to use high-precision equipment utilizing GNSS (satellite-based positioning). For example, if you connect a small RTK-GNSS receiver (a device like LRTK) to a smartphone, you can measure point-by-point positions with centimeter-level accuracy (half-inch accuracy) even at indoor-outdoor boundaries. They differ in accuracy, cost, and operational methods, so select according to the site’s needs.

Q3. Does implementing the system involve high costs? A. Compared with the past, the cost of implementing location information systems has fallen significantly. It is true that building a large-scale, full-coverage system requires a considerable investment, but if you start on a small scale you can use relatively inexpensive equipment. For example, commercially available BLE beacons are low-cost, and smartphone positioning devices such as LRTK are more affordable compared with traditional surveying equipment. Also, by using cloud services you can reduce initial costs and operate with a monthly subscription. You should be able to implement it within a manageable range according to your company's size and objectives.

Q4. Can workers who are not good with IT handle it? A. Yes. Recent positioning systems and devices are designed to be user-friendly and are engineered so they can be used without special expertise. The operation mainly involves intuitive actions such as viewing maps in a smartphone app and pressing a button to obtain a position. For example, with LRTK, coordinates are recorded simply by tapping a button on the smartphone screen at the location you want to measure, making it easier compared to traditional complex surveying equipment. With a short explanation and practice at the time of introduction, many field staff should be able to use it without problems.

Q5. In what kinds of worksites is it being adopted? A. Trial deployments are underway at large-scale building projects, plant construction, and infrastructure work sites. For example, at high-rise building construction sites it is used for equipment management and monitoring people flow; in tunnel construction for safety checks; and in factories and warehouses for worker location management and movement-path analysis. In Japan, some general contractors and equipment companies have begun conducting demonstration experiments and reporting results, and it is expected to spread to small- and medium-sized sites and the facilities management field in the future. The Ministry of Land, Infrastructure, Transport and Tourism has also promoted ICT construction and remote attendance (remote presence), and visualization of location information is an important technological element in that trend. The era when it will be commonly used at ever more worksites is coming.