How to Automate Location Management for Indoor Construction Sites: Real-Time Tracking of Workers and Materials

Table of Contents

• Challenges in location information management at indoor construction sites

• Benefits of automating location information management

• Location technologies available for indoor use

• Real-time tracking of workers

• Real-time tracking of materials and equipment

• Key points and precautions for implementation

• Simple surveying using LRTK

• FAQ

Challenges in Managing Location Information at Indoor Construction Sites

On construction sites, accurately tracking the whereabouts of workers and materials is essential for streamlining work processes and ensuring safety. However, at indoor construction sites, GPS-based positioning cannot be used as it can outdoors, making location information management a major challenge. With many workers and equipment moving around inside a large building, it is not easy to grasp "who is working where right now" or "where the necessary materials are located". As a result, responsible personnel end up confirming locations by radio or phone or walking around the large site to search, leading to decreased work efficiency and time loss.

Moreover, the inability to track location information in real time also affects safety. For example, in an emergency when everyone must be evacuated quickly, if the whereabouts of each worker cannot be determined, the risk to human life increases. Regarding materials, when required equipment cannot be found and workers end up searching around the site, project schedules can be delayed, and there is a risk of accidental loss or theft. In indoor construction management, it is difficult to obtain such location information, so managers have no choice but to rely on manual oversight, which becomes an additional burden.

Benefits of Automating Location Management

Automating location management is an effective solution to the above issues. By leveraging sensors and communication technologies to automatically detect and visualize the positions of people and objects, construction site management can be dramatically streamlined. For example, if the current locations of all workers on site can be displayed on a map in real time, supervisors can immediately see who is where even from the office. This enables them to instantly determine whether "workers are concentrated in a specific area" or "appropriate personnel are assigned to the necessary tasks", allowing for efficient, waste-free personnel allocation.

Improved safety is also a major benefit. A location management system can issue alerts when workers approach restricted areas, detect anomalies such as slips or falls, and promptly notify managers. Even if an accident occurs, because it is possible to immediately identify "who is where", rescue and evacuation can be carried out quickly. Additionally, by attaching tags to materials and equipment and tracking them, the on-site placement of materials becomes clear at a glance, reducing the time spent searching for items. By visualizing where and how many of the required materials are, it also helps prevent duplicate orders and streamlines inventory management.

In this way, the automation of location information management delivers benefits on both fronts: improving productivity (reducing the effort of searching, appropriate allocation of personnel, etc.) and enhancing safety (rapid response in accidents, hazard prediction, etc.). Furthermore, by accumulating and analyzing the collected location data, it becomes possible to discover new areas for improving construction management, such as optimizing workflows and improving layouts.

Indoor positioning technologies available for use

To monitor the real-time locations of people and objects on indoor construction sites, positioning technologies that can serve as alternatives to GPS are necessary. Representative indoor positioning technologies currently available include the following.

• BLE beacons: This method uses Bluetooth Low Energy signals emitted by small transmitters (beacons). Multiple BLE beacons are installed inside a building, and smartphones or dedicated receivers detect position by receiving those signals. Accuracy is generally on the order of a few meters (a few ft) in radius, but installation costs are low, they are battery-powered and require no wiring, so they can be easily deployed on construction sites. In addition, because beacons are detected only within the range their radio waves reach, it is easier to respect the privacy of workers who leave the site.

• UWB (Ultra-Wideband wireless): UWB signals use a wide frequency range in the several-GHz band and are a technology that enables high-precision positioning. Specialized tags are attached to workers and materials, and positions are triangulated by transmitting and responding between the tags and multiple fixed stations (antennas). Because UWB computes distance by time measurement at nanosecond-level resolution, it can achieve high-precision positioning with errors of tens of centimeters or less (tens of cm (a few to a few dozen in)). It provides stable accuracy even indoors, but compared with beacons the equipment cost is higher, and initial installation of tags and antennas is required. UWB positioning is attracting attention in large factories, plant construction sites, tunnel construction, and other situations where high accuracy is required.

• RFID: A radio-wave-based ID recognition technology applied to materials management. In particular, by attaching active RFID (battery-powered) tags to materials and detecting them with on-site readers, the whereabouts of materials can be recorded automatically. With passive RFID (battery-less), tags are only detected when brought close to a reader, but they are useful for applications such as automatically recording material entry and exit by installing gates. However, they do not provide real-time positioning and have limited range, so they are used complementarily in combination with other positioning technologies.

• Wi-Fi positioning: A method that estimates a device's location by using the signal strength of on-site Wi-Fi access points. It has the advantage of leveraging existing Wi-Fi infrastructure, but accuracy depends on access point density and radio conditions, and errors ranging from a few meters to the low tens of meters can occur. There are use cases in offices and commercial facilities; however, at construction sites with many walls and equipment, radio conditions tend to be unstable, and it is sometimes used as a supplementary positioning method alongside other techniques.

These technologies are not only used on their own but are also utilized in combination. For example, hybrid systems have been implemented that use GPS and satellite positioning outdoors and seamlessly switch to beacons or UWB when entering a building. There are also cases where accelerometers and barometric pressure sensors built into workers' helmets or mobile devices are used together to assist in fall detection and in tracking floor (level) movement. It is important to select the most appropriate technology according to site conditions and the required level of accuracy.

Real-time Worker Tracking

Automated location management systems make it possible to track workers' locations in real time. The system typically involves each worker wearing some kind of location-transmitting device. Specifically, this can include embedding UWB tags in safety helmets, having workers carry dedicated beacon tags, or installing a dedicated app on their smartphones and carrying them. Signals transmitted from these devices are picked up by receivers (antennas or beacon receivers) installed on site and converted into each person's location coordinates on cloud servers.

Administrators and supervisors can view that location information in real time on a computer or tablet screen. The current locations of workers are displayed as icons on the building's floor plan, making it immediately clear who is where. This makes worker movement management dramatically easier. For example, the leader of a work team can grasp the positions of members and issue precise directions to the next work location. Also, during break times or at the end of the shift, it is possible to confirm that people have returned to their designated places without having to make rounds.

Furthermore, some systems offer a geofence feature (setting virtual entry areas). If you set hazardous zones or no-entry areas on the map, then if a worker accidentally approaches such an area, the system can automatically sound an alarm or send a warning notification to their device. This can prevent unauthorized entry into restricted areas due to human error. Conversely, by detecting and alerting when an unqualified person attempts to enter an area restricted to workers with specific qualifications, you can strengthen safety management.

Even if an accident or disaster occurs on-site, the benefits of real-time tracking are immense. Because the system can instantly determine "which workers have not yet evacuated and where they are being left behind", rapid rescue operations and evacuation guidance become possible. In addition, by collecting and analyzing workers' movement path data, you can gain insights that lead to improved operational efficiency, such as "which locations tend to become crowded at which times" and "whether unnecessary movement is occurring."

Real-time Tracking of Materials and Equipment

Automating location management is also highly effective for tracking and managing materials and equipment on-site. Construction projects use a vast number of materials (structural steel, piping, cables, finishing materials, etc.) and various types of equipment (heavy machinery, generators, tools), and it can be a challenge just to know where they are across a large site. By implementing a location information system, you can monitor in real time the storage locations and operational status based on signals from tags attached to important materials and equipment.

For example, by installing GPS- and UWB-compatible location transmitters on large machines such as cranes and forklifts, you can track movement routes both indoors and outdoors. This allows you to record equipment operating status and usage frequency, and provides data to make decisions such as optimizing the number of machines if some remain idle for long periods. In addition, by attaching small electronic tags to material pallets and critical equipment, you can search the system to see which area they were placed in after being brought in or whether they have been moved. This reduces the time spent searching on site for "that material can't be found," allowing you to retrieve what you need right when you need it.

It is also effective for preventing theft and loss of materials. If you set it to trigger an alarm when tagged materials are taken out of the designated area, it will deter unauthorized removal. Especially for expensive measuring instruments and tools, location management is important even when they are moved between sites, and real-time tracking provides peace of mind by always keeping track of their whereabouts. Furthermore, by analyzing materials’ usage history data, you can identify trends such as which materials are frequently used in which processes and the rate at which inventory is depleted. This can help optimize material ordering timing and improve the layout of on-site material storage areas.

Key points and precautions when introducing

There are several points to keep in mind when introducing a location information management system to an indoor construction site. First, on the technical side, it is important to choose a positioning method suited to the scale and structure of the site. In buildings with a lot of steel framing, radio signals tend to reflect and attenuate easily, so antenna and beacon placement should be planned carefully and a sufficient number installed to avoid blind spots. If high accuracy is required, use UWB; if ease of use is prioritized, use BLE beacons—choose the technology according to the purpose.

Next, on the operational side, the key is to introduce it in a way that blends seamlessly into on-site workflows. If you track workers by having them carry smartphones, you need to ensure an environment where smartphones can be used on-site at all times (for example, waterproof cases and establishing the habit of carrying them). If you distribute dedicated tags, choose designs that won’t be obtrusive when attached to helmets or workwear, and manage them to prevent loss. Also, for battery-powered devices, plan regular charging and battery replacement so the system doesn’t stop when it matters.

Regarding implementation costs and effectiveness, it is recommended to first conduct a pilot deployment (PoC) on a limited scale to verify the effects before proceeding with full-scale implementation. For example, you could first try tracking workers' locations on a single floor and collect data on how much efficiency improves. If the effects are confirmed, gradually expanding the scope will allow you to roll out across the entire site smoothly while avoiding on-site disruption.

Furthermore, care must be taken in handling the collected location data. Out of consideration for workers' privacy, the information collected should be limited to what is necessary for operational purposes, and the data should be securely managed. It is important to communicate to everyone on site that location tracking is strictly for safety and efficiency—not for surveillance—and to create an environment where they can use it with confidence.

Simple Surveying with LRTK

To enable location information management both indoors and outdoors, it is essential not only to build positioning infrastructure but also to accurately determine the coordinates of buildings and reference points. For example, if the coordinates of beacon or antenna installation locations are measured in advance, the system can display positions more accurately. However, traditional surveying work requires specialist technicians and expensive equipment, and has lacked on-site responsiveness.

One approach gaining attention is simplified surveying using LRTK. LRTK is an innovative tool that, in conjunction with smartphones and tablets, achieves centimeter-level high-precision positioning. By simply attaching a dedicated compact receiver to a smartphone, anyone can easily obtain accurate position coordinates. For example, if a construction manager walks the site and measures key points with LRTK, interior survey drawings and the installation locations of equipment can be digitized in no time. Tasks that previously required hiring a surveying company can now be completed quickly by on-site personnel themselves, making "measure immediately when needed" a reality.

Our LRTK immediately uploads acquired coordinate data to the cloud, allowing it to be viewed in real time from an office PC. This lets you check on the spot whether points measured in the field match the drawings, and share data with team members in different locations to proceed with work. It also comes with a variety of functions—measuring height (elevation), calculating distances and areas, and even navigating installation positions using AR (augmented reality)—making it an all-purpose on-site tool that goes beyond mere surveying.

Simple surveying with LRTK provides powerful assistance in automating location information management at indoor construction sites. For example, when placing beacons for an indoor positioning system, measuring and registering each beacon’s precise location with LRTK improves subsequent tracking accuracy. Also, when remeasuring dimensions and layouts inside an existing building for renovation work, using LRTK allows you to grasp the current conditions in a short time. By leveraging such cutting-edge tools, location information management for people and objects indoors can be carried out more smoothly and with higher precision.

FAQ

Q1. Why can't GPS be used indoors? A. GPS is a positioning system that uses radio signals from satellites, but indoors the structure of buildings blocks those signals, making satellite signals difficult to reach. Therefore, inside buildings and underground, GPS receivers cannot acquire satellites, making it difficult to determine position. To obtain accurate location information indoors, it is necessary to use dedicated indoor positioning technologies as an alternative to GPS (such as beacons or UWB).

Q2. What technologies are used to track people and objects on construction sites? A. Various technologies are used depending on the application and accuracy requirements. Commonly, installing Bluetooth beacons on site and having workers' smartphones or dedicated tags receive the signals to determine location is an easy method. For higher accuracy, positioning using UWB tags and antennas is effective. In addition, RFID is used for material management, GPS is combined for large outdoor areas, and analysis of camera footage can be employed; multiple technologies are often combined.

Q3. How accurate are indoor positioning systems? A. It depends on the technology: BLE beacons typically provide accuracy on the order of several meters, while UWB can be expected to provide accuracy on the order of several tens of centimeters. Wi‑Fi positioning depends on the environment but is generally on the order of several meters to a dozen or so meters, and RFID depends on where the readers are installed. It is important to choose the appropriate technology based on the required accuracy. For example, if an error of a few meters is acceptable, you can build a low‑cost system with beacons; if you need more precise positioning, consider UWB.

Q4. How much does it cost to implement a location information management system? A. Implementation costs vary widely depending on the technology chosen and the scale of the site. Beacon-based systems are relatively inexpensive and can sometimes be started with a few dozen beacons and the application costs. High-precision systems such as UWB have higher per-unit prices for tags and antennas, and covering a wide area requires a correspondingly larger investment. However, with the recent spread of IoT technologies, device prices are declining, and it is possible to start small and expand in stages while assessing effectiveness. We recommend beginning with a pilot deployment to verify cost-effectiveness.

Q5. How is the privacy of collected location data ensured? A. When implementing the system, it is important to limit the data collected to what is necessary for business purposes. For example, configure settings that respect employees’ privacy by not monitoring detailed movements outside working hours or during breaks. Also, manage access permissions to the data so that unrelated parties cannot view individuals’ movement histories. Make it clear that location information is used strictly for safety management and operational efficiency, not for surveillance, which helps reassure employees.

Q6. Is there an easy way to perform surveying and alignment? A. To perform high-precision surveying on site, specialized surveying equipment is normally required, but recently there are simple surveying tools that utilize smartphones. A representative example is LRTK. By using LRTK, you can connect a small positioning device to a smartphone, allowing anyone to achieve centimeter-level positioning (half-inch accuracy). Because coordinates can be recorded with a single button without complicated operations, it can be used by people without surveying expertise. This enables you to measure reference point coordinates yourselves when installing indoor positioning systems and to quickly stake out the positions of structures during construction, contributing to improved accuracy in positional information management.